Summary: computeKnownBits is expensive. The cases that would be detected by the computeKnownBits portion of haveNoCommonBitsSet were already handled by the earlier call to SimplifyDemandedInstructionBits.
Reviewers: spatel, lebedev.ri
Reviewed By: lebedev.ri
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D50604
llvm-svn: 339531
This is a retry of rL339439 with a fix for the problem that
caused the original commit to be reverted at rL339446.
That problem was that the compare can be integer while
the binop is FP or vice-versa, so we need to use the binop
type when we ask for the identity constant.
A test to guard against the problem was added at rL339453.
llvm-svn: 339469
This accounts for the missing IR fold noted in D50195. We don't need any fast-math to enable the negation transform.
FP negation can always be folded into an fmul/fdiv constant to eliminate the fneg.
I've limited this to one-use to ensure that we are eliminating an instruction rather than replacing fneg by a
potentially expensive fdiv or fmul.
Differential Revision: https://reviews.llvm.org/D50417
llvm-svn: 339248
Summary:
https://rise4fun.com/Alive/IT3
Comes up in the [most ugliest] `signed int` -> `signed char` case of
`-fsanitize=implicit-conversion` (https://reviews.llvm.org/D50250)
Previously, we were stuck with `not`: {F6867736}
But now we are able to completely get rid of it: {F6867737}
(FIXME: why are we loosing the metadata? that seems wrong/strange.)
Here, we only want to do that it we will be able to completely
get rid of that 'not'.
Reviewers: spatel, craig.topper
Reviewed By: spatel
Subscribers: vsk, erichkeane, llvm-commits
Differential Revision: https://reviews.llvm.org/D50301
llvm-svn: 339243
In the past, DbgInfoIntrinsic has a strong assumption that these
intrinsics all have variables and expressions attached to them.
However, it is too strong to derive the class for other debug entities.
Now, it has problems for debug labels.
In order to make DbgInfoIntrinsic as a base class for 'debug info', I
create a class for 'variable debug info', DbgVariableIntrinsic.
DbgDeclareInst, DbgAddrIntrinsic, and DbgValueInst will be derived from it.
Differential Revision: https://reviews.llvm.org/D50220
llvm-svn: 338984
Workaround bug where the InstCombine pass was asserting on the IR added in lit
test, where we have a bitcast instruction after a GEP from an addrspace cast.
The second bitcast in the test was getting combined into
`bitcast <16 x i32>* %0 to <16 x i32> addrspace(3)*`, which looks like it should
be an addrspace cast instruction instead. Otherwise if control flow is allowed
to continue as it is now we create a GEP instruction
`<badref> = getelementptr inbounds <16 x i32>, <16 x i32>* %0, i32 0`. However
because the type of this instruction doesn't match the address space we hit an
assert when replacing the bitcast with that GEP.
```
void llvm::Value::doRAUW(llvm::Value*, bool): Assertion `New->getType() == getType() && "replaceAllUses of value with new value of different type!"' failed.
```
Differential Revision: https://reviews.llvm.org/D50058
llvm-svn: 338395
This fold was written in an odd way and tried to avoid
an endless loop by bailing out on all constants instead
of the supposedly problematic case of -1. But (X & -1)
should always be simplified before we reach here, so I'm
not sure how that is a problem.
There were no tests for the commuted patterns, so I added
those at rL338364.
llvm-svn: 338367
These are reassociated versions of the same pattern and
similar transforms as in rL338200 and rL338118.
The motivation is identical to those commits:
Patterns with add/sub combos can be improved using
'not' ops. This is better for analysis and may lead
to follow-on transforms because 'xor' and 'add' are
commutative/associative. It can also help codegen.
llvm-svn: 338221
https://rise4fun.com/Alive/jDd
Patterns with add/sub combos can be improved using
'not' ops. This is better for analysis and may lead
to follow-on transforms because 'xor' and 'add' are
commutative/associative. It can also help codegen.
llvm-svn: 338200
The tests with constants show a missing optimization.
Analysis for adds is better than subs, so this can also
help with other transforms. And codegen is better with
adds for targets like x86 (destructive ops, no sub-from).
https://rise4fun.com/Alive/llK
llvm-svn: 338118
InstCombine has a cast transform that matches a cast-of-select:
Orig = cast (Src = select Cond TV FV)
And tries to replace it with a select which has the cast folded in:
NewSel = select Cond (cast TV) (cast FV)
The combiner does RAUW(Orig, NewSel), so any debug values for Orig would
survive the transform. But debug values for Src would be lost.
This patch teaches InstCombine to replace all debug uses of Src with
NewSel (taking care of doing any necessary DIExpression rewriting).
Differential Revision: https://reviews.llvm.org/D49270
llvm-svn: 337310
Summary:
[[ https://bugs.llvm.org/show_bug.cgi?id=38149 | PR38149 ]]
As discussed in https://reviews.llvm.org/D49179#1158957 and later,
the IR for 'check for [no] signed truncation' pattern can be improved:
https://rise4fun.com/Alive/gBf
^ that pattern will be produced by Implicit Integer Truncation sanitizer,
https://reviews.llvm.org/D48958https://bugs.llvm.org/show_bug.cgi?id=21530
in signed case, therefore it is probably a good idea to improve it.
Proofs for this transform: https://rise4fun.com/Alive/mgu
This transform is surprisingly frustrating.
This does not deal with non-splat shift amounts, or with undef shift amounts.
I've outlined what i think the solution should be:
```
// Potential handling of non-splats: for each element:
// * if both are undef, replace with constant 0.
// Because (1<<0) is OK and is 1, and ((1<<0)>>1) is also OK and is 0.
// * if both are not undef, and are different, bailout.
// * else, only one is undef, then pick the non-undef one.
```
The DAGCombine will reverse this transform, see
https://reviews.llvm.org/D49266
Reviewers: spatel, craig.topper
Reviewed By: spatel
Subscribers: JDevlieghere, rkruppe, llvm-commits
Differential Revision: https://reviews.llvm.org/D49320
llvm-svn: 337190
The actual code seems to be correct, but the comments were misleading.
Patch by Aaron Puchert!
Differential Revision: https://reviews.llvm.org/D49276
llvm-svn: 337131
All predicates are handled.
There does not seem to be any other possible folds here.
There are some more folds possible with inverted mask though.
llvm-svn: 337112
This bug was created by rL335258 because we used to always call instsimplify
after trying the associative folds. After that change it became possible
for subsequent folds to encounter unsimplified code (and potentially assert
because of it).
Instead of carrying changed state through instcombine, we can just return
immediately. This allows instsimplify to run, so we can continue assuming
that easy folds have already occurred.
llvm-svn: 336965
Summary:
This patch is crucial for proving equality laundered/stripped
pointers. eg:
bool foo(A *a) {
return a == std::launder(a);
}
Clang with -fstrict-vtable-pointers will emit something like:
define dso_local zeroext i1 @_Z3fooP1A(%struct.A* %a) {
entry:
%c = bitcast %struct.A* %a to i8*
%call = tail call i8* @llvm.launder.invariant.group.p0i8(i8* %c)
%0 = bitcast %struct.A* %a to i8*
%1 = tail call i8* @llvm.strip.invariant.group.p0i8(i8* %0)
%2 = tail call i8* @llvm.strip.invariant.group.p0i8(i8* %call)
%cmp = icmp eq i8* %1, %2
ret i1 %cmp
}
and because %2 can be replaced with @llvm.strip.invariant.group(%0)
and that %2 and %1 will produce the same value (because strip is readnone)
we can replace compare with true.
Reviewers: rsmith, hfinkel, majnemer, amharc, kuhar
Subscribers: llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D47423
llvm-svn: 336963
This converts them to what clang is now using for codegen. Unfortunately, there seem to be a few kinks to work out still. I'll try to address with follow up patches.
llvm-svn: 336871
Summary:
https://bugs.llvm.org/show_bug.cgi?id=38123
This pattern will be produced by Implicit Integer Truncation sanitizer,
https://reviews.llvm.org/D48958https://bugs.llvm.org/show_bug.cgi?id=21530
in unsigned case, therefore it is probably a good idea to improve it.
https://rise4fun.com/Alive/Rny
^ there are more opportunities for folds, i will follow up with them afterwards.
Caveat: this somehow exposes a missing opportunities
in `test/Transforms/InstCombine/icmp-logical.ll`
It seems, the problem is in `foldLogOpOfMaskedICmps()` in `InstCombineAndOrXor.cpp`.
But i'm not quite sure what is wrong, because it calls `getMaskedTypeForICmpPair()`,
which calls `decomposeBitTestICmp()` which should already work for these cases...
As @spatel notes in https://reviews.llvm.org/D49179#1158760,
that code is a rather complex mess, so we'll let it slide.
Reviewers: spatel, craig.topper
Reviewed By: spatel
Subscribers: yamauchi, majnemer, t.p.northover, llvm-commits
Differential Revision: https://reviews.llvm.org/D49179
llvm-svn: 336834
This was originally intended with D48893, but as discussed there, we
have to make the folds safe from producing extra poison. This should
give the single binop folds the same capabilities as the existing
folds for 2-binops+shuffle.
LLVM binary opcode review: there are a total of 18 binops. There are 7
commutative binops (add, mul, and, or, xor, fadd, fmul) which we already
fold. We're able to fold 6 more opcodes with this patch (shl, lshr, ashr,
fdiv, udiv, sdiv). There are no folds for srem/urem/frem AFAIK. We don't
bother with sub/fsub with constant operand 1 because those are
canonicalized to add/fadd. 7 + 6 + 3 + 2 = 18.
llvm-svn: 336684
The case with 2 variables is more complicated than the case where
we eliminate the shuffle entirely because a shuffle with an undef
mask element creates an undef result.
I'm not aware of any current analysis/transform that recognizes that
undef propagating to a div/rem/shift, but we have to guard against
the possibility.
llvm-svn: 336668
getSafeVectorConstantForBinop() was calling getBinOpIdentity() assuming
that the constant we wanted was operand 1 (RHS). That's wrong, but I
don't think we could expose a bug or even a suboptimal fold from that
because the callers have other guards for any binop that would have
been affected.
llvm-svn: 336617
Summary:
Support for this option is needed for building Linux kernel.
This is a very frequently requested feature by kernel developers.
More details : https://lkml.org/lkml/2018/4/4/601
GCC option description for -fdelete-null-pointer-checks:
This Assume that programs cannot safely dereference null pointers,
and that no code or data element resides at address zero.
-fno-delete-null-pointer-checks is the inverse of this implying that
null pointer dereferencing is not undefined.
This feature is implemented in LLVM IR in this CL as the function attribute
"null-pointer-is-valid"="true" in IR (Under review at D47894).
The CL updates several passes that assumed null pointer dereferencing is
undefined to not optimize when the "null-pointer-is-valid"="true"
attribute is present.
Reviewers: t.p.northover, efriedma, jyknight, chandlerc, rnk, srhines, void, george.burgess.iv
Reviewed By: efriedma, george.burgess.iv
Subscribers: eraman, haicheng, george.burgess.iv, drinkcat, theraven, reames, sanjoy, xbolva00, llvm-commits
Differential Revision: https://reviews.llvm.org/D47895
llvm-svn: 336613
As discussed in D49047 / D48987, shift-by-undef produces poison,
so we can't use undef vector elements in that case..
Note that we need to extend this for poison-generating flags,
and there's a proposal to create poison from FMF in D47963,
llvm-svn: 336562
This is almost NFC, but there could be some case where the original
code had undefs in the constants (rather than just the shuffle mask),
and we'll use safe constants rather than undefs now.
The FIXME noted in foldShuffledBinop() is already visible in existing
tests, so correcting that is the next step.
llvm-svn: 336558
As noted in D48987, there are many different ways for this transform to go wrong.
In particular, the poison potential for shifts means we have to more careful with those ops.
I added tests to make that behavior visible for all of the different cases that I could find.
This is a partial fix. To make this review easier, I did not make changes for the single binop
pattern (handled in foldSelectShuffleWith1Binop()). I also left out some potential optimizations
noted with TODO comments. I'll follow-up once we're confident that things are correct here.
The goal is to correct all marked FIXME tests to either avoid the shuffle transform or do it safely.
Note that distinguishing when the shuffle mask contains undefs and using getBinOpIdentity() allows
for some improvements to div/rem patterns, so there are wins along with the missed opportunities
and fixes.
Differential Revision: https://reviews.llvm.org/D49047
llvm-svn: 336546
It's a bit neater to write T.isIntOrPtrTy() over `T.isIntegerTy() ||
T.isPointerTy()`.
I used Python's re.sub with this regex to update users:
r'([\w.\->()]+)isIntegerTy\(\)\s*\|\|\s*\1isPointerTy\(\)'
llvm-svn: 336462
The replaceAllDbgUsesWith utility helps passes preserve debug info when
replacing one value with another.
This improves upon the existing insertReplacementDbgValues API by:
- Updating debug intrinsics in-place, while preventing use-before-def of
the replacement value.
- Falling back to salvageDebugInfo when a replacement can't be made.
- Moving the responsibiliy for rewriting llvm.dbg.* DIExpressions into
common utility code.
Along with the API change, this teaches replaceAllDbgUsesWith how to
create DIExpressions for three basic integer and pointer conversions:
- The no-op conversion. Applies when the values have the same width, or
have bit-for-bit compatible pointer representations.
- Truncation. Applies when the new value is wider than the old one.
- Zero/sign extension. Applies when the new value is narrower than the
old one.
Testing:
- check-llvm, check-clang, a stage2 `-g -O3` build of clang,
regression/unit testing.
- This resolves a number of mis-sized dbg.value diagnostics from
Debugify.
Differential Revision: https://reviews.llvm.org/D48676
llvm-svn: 336451
Better NaN handling for AMDGCN fmed3.
All operands are checked for NaN now. The checks
were moved before the canonicalization to provide
a better mapping from fclamp. Changed the behaviour
of fmed3(x,y,NaN) to return max(x,y) instead of
min(x,y) in light of this. Updated tests as a result
and added some new cases to cover the fix.
Patch by Alan Baker
llvm-svn: 336375
We have bailout hacks based on min/max in various places in instcombine
that shouldn't be necessary. The affected test was added for:
D48930
...which is a consequence of the improvement in:
D48584 (https://reviews.llvm.org/rL336172)
I'm assuming the visitTrunc bailout in this patch was added specifically
to avoid a change from SimplifyDemandedBits, so I'm just moving that
below the EvaluateInDifferentType optimization. A narrow min/max is still
a min/max.
llvm-svn: 336293
When zext is EvaluatedInDifferentType, InstCombine
drops the dbg.value intrinsic. This patch tries to
preserve said DI, by inserting the zext's old DI in the
resulting instruction. (Only for integer type for now)
Differential Revision: https://reviews.llvm.org/D48331
llvm-svn: 336254
This is the last significant change suggested in PR37806:
https://bugs.llvm.org/show_bug.cgi?id=37806#c5
...though there are several follow-ups noted in the code comments
in this patch to complete this transform.
It's possible that a binop feeding a select-shuffle has been eliminated
by earlier transforms (or the code was just written like this in the 1st
place), so we'll fail to match the patterns that have 2 binops from:
D48401,
D48678,
D48662,
D48485.
In that case, we can try to materialize identity constants for the remaining
binop to fill in the "ghost" lanes of the vector (where we just want to pass
through the original values of the source operand).
I added comments to ConstantExpr::getBinOpIdentity() to show planned follow-ups.
For now, we only handle the 5 commutative integer binops (add/mul/and/or/xor).
Differential Revision: https://reviews.llvm.org/D48830
llvm-svn: 336196
This patch changes order of transform in InstCombineCompares to avoid
performing transforms based on ranges which produce complex bit arithmetics
before more simple things (like folding with constants) are done. See PR37636
for the motivating example.
Differential Revision: https://reviews.llvm.org/D48584
Reviewed By: spatel, lebedev.ri
llvm-svn: 336172
This extends D48485 to allow another pair of binops (add/or) to be combined either
with or without a leading shuffle:
or X, C --> add X, C (when X and C have no common bits set)
Here, we need value tracking to determine that the 'or' can be reversed into an 'add',
and we've added general infrastructure to allow extending to other opcodes or moving
to where other passes could use that functionality.
Differential Revision: https://reviews.llvm.org/D48662
llvm-svn: 336128
This was discussed in D48401 as another improvement for:
https://bugs.llvm.org/show_bug.cgi?id=37806
If we have 2 different variable values, then we shuffle (select) those lanes,
shuffle (select) the constants, and then perform the binop. This eliminates a binop.
The new shuffle uses the same shuffle mask as the existing shuffle, so there's no
danger of creating a difficult shuffle.
All of the earlier constraints still apply, but we also check for extra uses to
avoid creating more instructions than we'll remove.
Additionally, we're disallowing the fold for div/rem because that could expose a
UB hole.
Differential Revision: https://reviews.llvm.org/D48678
llvm-svn: 335974
There's no way to expose this difference currently,
but we should use the updated variable because the
original opcodes can go stale if we transform into
something new.
llvm-svn: 335920
This is an enhancement to D48401 that was discussed in:
https://bugs.llvm.org/show_bug.cgi?id=37806
We can convert a shift-left-by-constant into a multiply (we canonicalize IR in the other
direction because that's generally better of course). This allows us to remove the shuffle
as we do in the regular opcodes-are-the-same cases.
This requires a small hack to make sure we don't introduce any extra poison:
https://rise4fun.com/Alive/ZGv
Other examples of opcodes where this would work are add+sub and fadd+fsub, but we already
canonicalize those subs into adds, so there's nothing to do for those cases AFAICT. There
are planned enhancements for opcode transforms such or -> add.
Note that there's a different fold needed if we've already managed to simplify away a binop
as seen in the test based on PR37806, but we manage to get that one case here because this
fold is positioned above the demanded elements fold currently.
Differential Revision: https://reviews.llvm.org/D48485
llvm-svn: 335888
I think the intrinsics named 'avx512.mask.' should refer to the previous behavior of taking a mask argument in the intrinsic instead of using a 'select' or 'and' instruction in IR to accomplish the masking. This is more consistent with the goal that eventually we will have no intrinsics that have masking builtin. When we reach that goal, we should have no intrinsics named "avx512.mask".
llvm-svn: 335744
This prevents InstCombine from creating mis-sized dbg.values when
replacing a sequence of casts with a simpler cast. For example, in:
(fptrunc (floor (fpext X))) -> (floorf X)
We no longer emit dbg.value(X) (with a 32-bit float operand) to describe
(fpext X) (which is a 64-bit float).
This was diagnosed by the debugify check added in r335682.
llvm-svn: 335696
Similar to other patches in this series:
https://reviews.llvm.org/rL335512https://reviews.llvm.org/rL335527https://reviews.llvm.org/rL335597https://reviews.llvm.org/rL335616
...this is filling a gap in analysis that is exposed by an unrelated select-of-constants transform.
I didn't see a way to unify the sext cases because each div/rem opcode results in a different fold.
Note that in this case, the backend might want to convert the select into math:
Name: sext urem
%e = sext i1 %x to i32
%r = urem i32 %y, %e
=>
%c = icmp eq i32 %y, -1
%z = zext i1 %c to i32
%r = add i32 %z, %y
llvm-svn: 335622
Note: I didn't add a hasOneUse() check because the existing,
related fold doesn't have that check. I suspect that the
improved analysis and codegen make these some of the rare
canonicalization cases where we allow an increase in
instructions.
llvm-svn: 335597
Turn canonicalized subtraction back into (-1 - B) and combine it with (A + 1) into (A - B).
This is similar to the folding already done for (B ^ -1) + Const into (-1 + Const) - B.
Differential Revision: https://reviews.llvm.org/D48535
llvm-svn: 335579
This removes a "UDivFoldAction" in favor of a simple constant
matcher. In theory, the existing code could do more matching,
but I don't see any evidence or need for it. I've left a TODO
about using ValueTracking in case we see any regressions.
llvm-svn: 335545
With non-commutative binops, we could be using the same
variable value as operand 0 in 1 binop and operand 1 in
the other, so we have to check for that possibility and
bail out.
llvm-svn: 335312
This is the simplest case from PR37806:
https://bugs.llvm.org/show_bug.cgi?id=37806
If we have a common variable operand used in a pair of binops with vector constants
that are vector selected together, then we can constant shuffle the constant vectors
to eliminate the shuffle instruction.
This has some tricky parts that are hopefully addressed in the tests and their
respective comments:
1. If the shuffle mask contains an undef element, then that lane of the result is
undef:
http://llvm.org/docs/LangRef.html#shufflevector-instruction
Therefore, we can replace the constant in that lane with an undef value except
for div/rem. With div/rem, an undef in the divisor would cause the whole op to
be undef. So I'm using the same hack as in D47686 - replace the undefs with '1'.
2. Intersect the wrapping and FMF of the original binops for the new binop. There
should be no extra poison or fast-math potential in the new binop that wasn't
possible in the original code.
3. Disregard other uses. Given that we're eliminating uses (shortening the
dependency chain), I think that's always the right IR canonicalization. But
I purposely chose the udiv test to demonstrate the scenario where both
intermediate values have other uses because that seems likely worse for
codegen with an expensive math op. This seems like a very rare possibility to
me, so I don't think it requires a backend patch first.
Differential Revision: https://reviews.llvm.org/D48401
llvm-svn: 335283
The previous code worked with vectors, but it failed when the
vector constants contained undef elements.
The matchers handle those cases.
llvm-svn: 335262
This is outwardly NFC from what I can tell, but it should be more efficient
to simplify first (despite the name, SimplifyAssociativeOrCommutative does
not actually simplify as InstSimplify does - it creates/morphs instructions).
This should make it easier to refactor duplicated code that runs for all binops.
llvm-svn: 335258
Summary:
This also removes the need for atomic pseudo instructions, since
we select the correct encoding directly in SITargetLowering::lowerImage
for dimension-aware image intrinsics.
Mesa uses dimension-aware image intrinsics since
commit a9a7993441.
Change-Id: I7473d20009476a4ed6d919cae4e6dca9ff42e77a
Reviewers: arsenm, rampitec, mareko, tpr, b-sumner
Subscribers: kzhuravl, wdng, yaxunl, dstuttard, t-tye, llvm-commits
Differential Revision: https://reviews.llvm.org/D48167
llvm-svn: 335231
Summary:
Use the expanded features of the TableGen generic tables to avoid manually
adding the combinatorially exploded set of intrinsics. The
getAMDGPUImageDimIntrinsic lookup function is early-out,
i.e. non-AMDGPU intrinsics will never look at the underlying table.
Use a generic approach for getting the new intrinsic overload to keep the
code simple, and make the image dmask handling more generic:
- handle non-sampler image loads
- handle the case where the set of demanded elements is not a prefix
There is some overlap between this code and an optimization that happens
in the backend during code generation. They currently complement each other:
- only the codegen optimization can generate vec3 loads
- only the InstCombine optimization can handle D16
The InstCombine optimization also likely covers more cases since the
codegen optimization is fairly ad-hoc. Ideally, we'll remove the optimization
in codegen once the infrastructure for vec3 is in place (which will probably
take a long time).
Modify the test cases to use dimension-aware intrinsics. This makes it
easier to see that the test coverage for the new intrinsics is equivalent,
and the old style intrinsics will be removed in a follow-up commit anyway.
Change-Id: I4b91ea661413d13004956fe4ef7d13d41b8ce3ad
Reviewers: arsenm, rampitec, majnemer
Subscribers: kzhuravl, wdng, mgorny, yaxunl, dstuttard, tpr, t-tye, llvm-commits
Differential Revision: https://reviews.llvm.org/D48165
llvm-svn: 335230
The purpose of this utility is to make it easier for optimizations to
insert replacement dbg.values for instructions they are deleting. This
is useful in situations where salvageDebugInfo is inapplicable, say,
because the new dbg.value cannot refer to an operand of the dying value.
The utility is called insertReplacementDbgValues.
It assumes that the instruction 'From' is going to be deleted, and
inserts replacement dbg.values for each debug user of 'From'. The
newly-inserted dbg.values refer to 'To' instead of 'From'. Each
replacement dbg.value has the same location and variable as the debug
user it replaces, has a DIExpression determined by the result of
'RewriteExpr' applied to an old debug user of 'From', and is placed
before 'InsertBefore'.
This should simplify future patches, like D48331.
llvm-svn: 335144
Summary:
Related to https://bugs.llvm.org/show_bug.cgi?id=37793, https://reviews.llvm.org/D46760#1127287
We'd like to do this canonicalization https://rise4fun.com/Alive/Gmc
But it is currently restricted by rL155136 / rL155362, which says:
```
// This is a constant shift of a constant shift. Be careful about hiding
// shl instructions behind bit masks. They are used to represent multiplies
// by a constant, and it is important that simple arithmetic expressions
// are still recognizable by scalar evolution.
//
// The transforms applied to shl are very similar to the transforms applied
// to mul by constant. We can be more aggressive about optimizing right
// shifts.
//
// Combinations of right and left shifts will still be optimized in
// DAGCombine where scalar evolution no longer applies.
```
I think these tests show that for *constants*, SCEV has no issues with that canonicalization.
Reviewers: mkazantsev, spatel, efriedma, sanjoy
Reviewed By: mkazantsev
Subscribers: sanjoy, javed.absar, llvm-commits, stoklund, bixia
Differential Revision: https://reviews.llvm.org/D48229
llvm-svn: 335101
This patch introduces two helpers to make it easier to ignore debug
intrinsics:
- Instruction::getNextNonDebugInstruction()
This is just like Instruction::getNextNode(), except that it skips debug
info.
- skipDebugInfo(BasicBlock::iterator)
A free function which advances a BasicBlock iterator past any debug
info. This is a no-op when the iterator already points to a non-debug
instruction.
Part of: llvm.org/PR37728
Related to: https://reviews.llvm.org/D47874
Differential Revision: https://reviews.llvm.org/D48305
llvm-svn: 335083
This patch replaces calls to X86-specific intrinsics with floor-ceil semantics
with calls to target-independent @llvm.floor.* and @llvm.ceil.* intrinsics. This
doesn't affect the resulting machine code, as those intrinsics are lowered to
the same instructions, but exposes these specific rounding cases to generic
optimizations.
Differential Revision: https://reviews.llvm.org/D48067
llvm-svn: 335039
Summary:
When iterating users of a multiply in processUMulZExtIdiom, the
call to setOperand in the truncation case may replace the use
being visited; make sure the iterator has been advanced before
doing that replacement.
Reviewers: majnemer, davide
Reviewed By: davide
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D48192
llvm-svn: 334844
Summary:
We already do it for splat constants, but not just values.
Also, undef cases are mostly non-functional.
The original commit was reverted because
it broke tests for amdgpu backend, which i didn't check.
Now, the backed was updated to recognize these new
patterns, so we are good.
https://bugs.llvm.org/show_bug.cgi?id=37603https://rise4fun.com/Alive/cplX
Reviewers: spatel, craig.topper, mareko, bogner, rampitec, nhaehnle, arsenm
Reviewed By: spatel, rampitec, nhaehnle
Subscribers: wdng, nhaehnle, llvm-commits
Differential Revision: https://reviews.llvm.org/D47980
llvm-svn: 334818
The bug report:
https://bugs.llvm.org/show_bug.cgi?id=36036
...requests a DAG change for this, but an IR canonicalization
probably handles most cases. If we still want to match this
pattern in the backend, there's a proposal for that too:
D47831
Alive proofs including nsw/nuw cases that were first noted in:
D46988
https://rise4fun.com/Alive/Kmp
This patch is largely copied from the existing code that was
initially added with:
D40984
...but I didn't see much gain from trying to share code.
llvm-svn: 334137
Summary:
This is [[ https://bugs.llvm.org/show_bug.cgi?id=37603 | PR37603 ]].
https://godbolt.org/g/VCMNpShttps://rise4fun.com/Alive/idM
When doing bit manipulations, it is quite common to calculate some bit mask,
and apply it to some value via `and`.
The typical C code looks like:
```
int mask_signed_add(int nbits) {
return (1 << nbits) - 1;
}
```
which is translated into (with `-O3`)
```
define dso_local i32 @mask_signed_add(int)(i32) local_unnamed_addr #0 {
%2 = shl i32 1, %0
%3 = add nsw i32 %2, -1
ret i32 %3
}
```
But there is a second, less readable variant:
```
int mask_signed_xor(int nbits) {
return ~(-(1 << nbits));
}
```
which is translated into (with `-O3`)
```
define dso_local i32 @mask_signed_xor(int)(i32) local_unnamed_addr #0 {
%2 = shl i32 -1, %0
%3 = xor i32 %2, -1
ret i32 %3
}
```
Since we created such a mask, it is quite likely that we will use it in `and` next.
And then we may get rid of `not` op by folding into `andn`.
But now that i have actually looked:
https://godbolt.org/g/VTUDmU
_some_ backend changes will be needed too.
We clearly loose `bzhi` recognition.
Reviewers: spatel, craig.topper, RKSimon
Reviewed By: spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47428
llvm-svn: 334127
We should never get different CodeGen based on whether the code is being
compiled in debug mode so we must skip over @llvm.dbg.value (and similar)
calls.
Should fix at least the worst part of PR37690.
llvm-svn: 334090
When adjusting a cmp in order to canonicalize an abs/nabs select pattern we need
to use the type of the existing operand when creating a new operand not the
type of a select operand, as the two may be different.
This fixes PR37686.
llvm-svn: 334019
As noted in rL333782, we can be both better for optimization and
safer with this transform:
BinOp (shuffle V1, Mask), C --> shuffle (BinOp V1, NewC), Mask
The only potentially unsafe-to-speculate binops are integer div/rem.
All other binops are always safe (although I don't see a way to
assert that in code here).
For opcodes like shifts that can produce poison, it can't matter
here because we know the lanes with undef are dropped by the
subsequent shuffle.
Differential Revision: https://reviews.llvm.org/D47686
llvm-svn: 333962
Review feedback from r328165. Split out just the one function from the
file that's used by Analysis. (As chandlerc pointed out, the original
change only moved the header and not the implementation anyway - which
was fine for the one function that was used (since it's a
template/inlined in the header) but not in general)
llvm-svn: 333954
When we optimize select basing on fact that div by 0 is undef
we should not traverse the instruction which are not guaranteed to
transfer execution to next instruction. Guard intrinsic is an example.
Reviewers: spatel, craig.topper
Reviewed By: spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47576
llvm-svn: 333864
There's a patchwork of existing transforms trying to handle
these cases, but as seen in the changed test, we weren't
catching them all.
llvm-svn: 333845
As noted in the review thread for rL333782, we could have
made a bug harder to hit if we were simplifying instructions
before trying other folds.
The shuffle transform in question isn't ever a simplification;
it's just a canonicalization. So I've renamed that to make that
clearer.
This is NFCI at this point, but I've regenerated the test file
to show the cosmetic value naming difference of using
instcombine's RAUW vs. the builder.
Possible follow-ups:
1. Move reassociation folds after simplifies too.
2. Refactor common code; we shouldn't have so much repetition.
llvm-svn: 333820
This bug:
https://bugs.llvm.org/show_bug.cgi?id=37648
...was created with the enhancement to this transform with rL332479.
The urem test shows the disaster potential: any undef divisor lane makes
the whole op undef.
The test diffs show that vector demanded elements turns some of the potential,
but not all, unused binop operands back into undef already.
llvm-svn: 333782
This is the planned enhancement to D47163 / rL333611.
We want to match cmp/select sizes because that will be recognized
as min/max more easily and lead to better codegen (especially for
vector types).
As mentioned in D47163, this improves some of the tests that would
also be folded by D46380, so we may want to adjust that patch to
match the new patterns where the extend op occurs after the select.
llvm-svn: 333689
Convert a vector load intrinsic into an llvm load instruction.
This is beneficial when the underlying object being addressed
comes from a constant, since we get constant-folding for free.
Differential Revision: https://reviews.llvm.org/D46273
llvm-svn: 333643
In post-commit review, Eric Christopher notes that many
new MSan warnings are being observed with this patch.
The probable reason is: if 'y' is undef here and we could
evaluate it twice and get different results.
We can't increase the number of uses of a value.
llvm-svn: 333631
Don't always:
cast (select (cmp x, y), z, C) --> select (cmp x, y), (cast z), C'
This is something that came up as far back as D26556, and I lost track of it.
I suspect that this transform is part of the underlying problem that is
inspiring some of the recent proposals that seek to match larger patterns
that include a cast op. Even if that's not true, this transform causes
problems for codegen (particularly with vector types).
A transform to actively match the size of cmp and select operand sizes should
follow. This patch just removes the harmful canonicalization in the other
direction.
Differential Revision: https://reviews.llvm.org/D47163
llvm-svn: 333611
Turning a table lookup intrinsic into a shuffle vector instruction
can be beneficial. If the mask used for the lookup is the constant
vector {7,6,5,4,3,2,1,0}, then the back-end generates byte reverse
instructions instead.
Differential Revision: https://reviews.llvm.org/D46133
llvm-svn: 333550
The ARM/ARM64 AESE and AESD instructions have a builtin XOR as the first step in
the instruction. Therefore, if the AES key is zero and the AES data was
previously XORed, it can be combined into a single instruction.
Differential Revision: https://reviews.llvm.org/D47239
Patch by Michael Brase!
llvm-svn: 333193
Summary:
Finally fixes [[ https://bugs.llvm.org/show_bug.cgi?id=6773 | PR6773 ]].
Now that the backend is all done, we can finally fold it!
The canonical unfolded masked merge pattern is
```(x & m) | (y & ~m)```
There is a second, equivalent variant:
```(x | ~m) & (y | m)```
Only one of them (the or-of-and's i think) is canonical.
And if the mask is not a constant, we should fold it to:
```((x ^ y) & M) ^ y```
https://rise4fun.com/Alive/ndQw
Reviewers: spatel, craig.topper
Reviewed By: spatel
Subscribers: nicholas, RKSimon, llvm-commits
Differential Revision: https://reviews.llvm.org/D46814
llvm-svn: 333106
We can eliminate old value if bound_ctrl = 1 and row_mask = bank_mask = 0xf.
This is alternative implementation working with the intrinsic in InstCombine.
Original review for past-ISel optimization: D46570.
Differential Revision: https://reviews.llvm.org/D46596
llvm-svn: 332956
Summary:
This patch fixes PR37526 by simplifying the newly generated LoadInst
instructions. If the pointer address is a bitcast from the pointer to
the NewType, we can just remove this extra bitcast instead of creating
the new one. This fixes the PR37526 + may speed up the whole compilation
process.
Reviewers: spatel, RKSimon, hfinkel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47144
llvm-svn: 332855
We already do this for min/max (see the blob above the diff),
so we should do the same for abs/nabs.
A sign-bit check (<s 0) is used as a predicate for other IR
transforms and it's likely the best for codegen.
This might solve the motivating cases for D47037 and D47041,
but I think those patches still make sense. We can't guarantee
this canonicalization if the icmp has more than one use.
Differential Revision: https://reviews.llvm.org/D47076
llvm-svn: 332819
Summary:
- Add wasm personality function
- Re-categorize the existing `isFuncletEHPersonality()` function into
two different functions: `isFuncletEHPersonality()` and
`isScopedEHPersonality(). This becomes necessary as wasm EH uses scoped
EH instructions (catchswitch, catchpad/ret, and cleanuppad/ret) but not
outlined funclets.
- Changed some callsites of `isFuncletEHPersonality()` to
`isScopedEHPersonality()` if they are related to scoped EH IR-level
stuff.
Reviewers: majnemer, dschuff, rnk
Subscribers: jfb, sbc100, jgravelle-google, eraman, JDevlieghere, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D45559
llvm-svn: 332667
According to alive this is valid. I'm hoping to use this to make an assumption that the sign bit is zero after this sequence. The only way it wouldn't be is if the input was INT__MIN, but by preserving the flags we can make doing this to INT_MIN UB.
The nuw flags is weird because it creates such a contradiction that the original number would have to be positive meaning we could remove the select entirely, but we don't get that far.
Differential Revision: https://reviews.llvm.org/D46988
llvm-svn: 332623
The canonicalization was restricted to shuffle masks with
a 1-to-1 mapping to the constant vector, but that disqualifies
the common splat pattern. This is part of solving PR37463:
https://bugs.llvm.org/show_bug.cgi?id=37463
llvm-svn: 332479
Summary:
Part of the InstCombine code for simplifying GEPs looks through
addrspacecasts. However, this was done by updating a variable
also used by the next transformation, for marking GEPs as
inbounds. This led to replacing a GEP with a similar instruction
in a different addrspace, which caused an assertion failure in RAUW.
This caused julia issue https://github.com/JuliaLang/julia/issues/27055
Patch by Jeff Bezanson <jeff@juliacomputing.com>
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D46722
llvm-svn: 332302
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.
In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.
Differential Revision: https://reviews.llvm.org/D43624
llvm-svn: 332240
Summary:
This change adds handling of the atomic memset intrinsic to the
code path that simplifies the regular memset. In practice this means
that we will now also expand a small constant-length atomic memset
into a single unordered atomic store.
Reviewers: apilipenko, skatkov, mkazantsev, anna, reames
Reviewed By: reames
Subscribers: reames, llvm-commits
Differential Revision: https://reviews.llvm.org/D46660
llvm-svn: 332132
Summary:
This change reworks the handling of atomic memcpy within the instcombine pass.
Previously, a constant length atomic memcpy would be lowered into loads & stores
as long as no more than 16 load/store pairs are created. This is quite different
from the lowering done for a non-atomic memcpy; which only ever lowers into a single
load/store pair of no more than 8 bytes. Larger constant-sized memcpy calls are
expanded to load/stores in later passes, such as SelectionDAG lowering.
In this change the behaviour for atomic memcpy is unified with non-atomic memcpy;
atomic memcpy is now treated in the same was as non-atomic memcpy has always been.
We leave it to later passes to lower longer-length atomic memcpy calls.
Due to the structure of the pass's handling of memtransfer intrinsics, this change
also gives us handling of atomic memmove that we did not previously have.
Reviewers: apilipenko, skatkov, mkazantsev, anna, reames
Reviewed By: reames
Subscribers: reames, llvm-commits
Differential Revision: https://reviews.llvm.org/D46658
llvm-svn: 332093
The bitwidth of the operation should always be wider than the result width of the truncate since we don't recurse through any width changing operations.
llvm-svn: 332055
Put in a conservatively correct estimate for now. Avoids miscompiling
clang in FDO mode. This is really tricky to trigger in reality as
basically all interesting cases will be folded away by computeKnownBits
earlier, I was unable to find a reasonably small test case.
llvm-svn: 331975
The previous handling for guard widening in InstCombine was extremely restrictive. In particular, it didn't handle the common case where we had two guards separated by a single icmp. Handle this by scanning through a small fixed window of instructions to find the next guard if needed.
Differential Revision: https://reviews.llvm.org/D46203
llvm-svn: 331935
This is safe as long as the udiv is not exact. The pattern is not common in
C++ code, but comes up all the time in code generated by XLA's GPU backend.
Differential Revision: https://reviews.llvm.org/D46647
llvm-svn: 331933
Inspired by r331508, I did a grep and found these.
Mostly just change from dyn_cast to cast. Some cases also showed a dyn_cast result being converted to bool, so those I changed to isa.
llvm-svn: 331577
Add logic for the special case when a cmp+select can clearly be
reduced to just a bitwise logic instruction, and remove an
over-reaching chunk of general purpose bit magic. The primary goal
is to remove cases where we are not improving the IR instruction
count when doing these select transforms, and in all cases here that
is true.
In the motivating 3-way compare tests, there are further improvements
because we can combine/propagate select values (not sure if that
belongs in instcombine, but it's there for now).
DAGCombiner has folds to turn some of these selects into bit magic,
so there should be no difference in the end result in those cases.
Not all constant combinations are handled there yet, however, so it
is possible that some targets will see more cmov/csel codegen with
this change in IR canonicalization.
Ideally, we'll go further to *not* turn selects into multiple
logic/math ops in instcombine, and we'll canonicalize to selects.
But we should make sure that this step does not result in regressions
first (and if it does, we should fix those in the backend).
The general direction for this change was discussed here:
http://lists.llvm.org/pipermail/llvm-dev/2016-September/105373.htmlhttp://lists.llvm.org/pipermail/llvm-dev/2017-July/114885.html
Alive proofs for the new bit magic:
https://rise4fun.com/Alive/XG7
Differential Revision: https://reviews.llvm.org/D46086
llvm-svn: 331486
This is a follow-up to r331272.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\@brief'); do perl -pi -e 's/\@brief //g' $i & done
https://reviews.llvm.org/D46290
llvm-svn: 331275
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46290
llvm-svn: 331272
Summary:
As discussed in D45733, we want to do this in InstCombine.
https://rise4fun.com/Alive/LGk
Reviewers: spatel, craig.topper
Reviewed By: spatel
Subscribers: chandlerc, xbolva00, llvm-commits
Differential Revision: https://reviews.llvm.org/D45867
llvm-svn: 331205
Summary:
Masked merge has a pattern of: `((x ^ y) & M) ^ y`.
But, there is no difference between `((x ^ y) & M) ^ y` and `((x ^ y) & ~M) ^ x`,
We should canonicalize the pattern to non-inverted mask.
https://rise4fun.com/Alive/Yol
Reviewers: spatel, craig.topper
Reviewed By: spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45664
llvm-svn: 331112
Summary:
Currently, we
1. match `LHS` matcher to the `first` operand of binary operator,
2. and then match `RHS` matcher to the `second` operand of binary operator.
If that does not match, we swap the `LHS` and `RHS` matchers:
1. match `RHS` matcher to the `first` operand of binary operator,
2. and then match `LHS` matcher to the `second` operand of binary operator.
This works ok.
But it complicates writing of commutative matchers, where one would like to match
(`m_Value()`) the value on one side, and use (`m_Specific()`) it on the other side.
This is additionally complicated by the fact that `m_Specific()` stores the `Value *`,
not `Value **`, so it won't work at all out of the box.
The last problem is trivially solved by adding a new `m_c_Specific()` that stores the
`Value **`, not `Value *`. I'm choosing to add a new matcher, not change the existing
one because i guess all the current users are ok with existing behavior,
and this additional pointer indirection may have performance drawbacks.
Also, i'm storing pointer, not reference, because for some mysterious-to-me reason
it did not work with the reference.
The first one appears trivial, too.
Currently, we
1. match `LHS` matcher to the `first` operand of binary operator,
2. and then match `RHS` matcher to the `second` operand of binary operator.
If that does not match, we swap the ~~`LHS` and `RHS` matchers~~ **operands**:
1. match ~~`RHS`~~ **`LHS`** matcher to the ~~`first`~~ **`second`** operand of binary operator,
2. and then match ~~`LHS`~~ **`RHS`** matcher to the ~~`second`~ **`first`** operand of binary operator.
Surprisingly, `$ ninja check-llvm` still passes with this.
But i expect the bots will disagree..
The motivational unittest is included.
I'd like to use this in D45664.
Reviewers: spatel, craig.topper, arsenm, RKSimon
Reviewed By: craig.topper
Subscribers: xbolva00, wdng, llvm-commits
Differential Revision: https://reviews.llvm.org/D45828
llvm-svn: 331085
Summary:
Simplify integer add expression X % C0 + (( X / C0 ) % C1) * C0 to
X % (C0 * C1). This is a common pattern seen in code generated by the XLA
GPU backend.
Add test cases for this new optimization.
Patch by Bixia Zheng!
Reviewers: sanjoy
Reviewed By: sanjoy
Subscribers: efriedma, craig.topper, lebedev.ri, llvm-commits, jlebar
Differential Revision: https://reviews.llvm.org/D45976
llvm-svn: 330992
As discussed in D45862, we want to delete parts of
this code because it can create more instructions
than it removes. But we also want to preserve some
folds that are winners, so tidy up what's here to
make splitting the good from bad a bit easier.
llvm-svn: 330841
(notionally Scalar.h is part of libLLVMScalarOpts, so it shouldn't be
included by InstCombine which doesn't/shouldn't need to depend on
ScalarOpts)
llvm-svn: 330669
This is the last step in getting constant pattern matchers to allow
undef elements in constant vectors.
I'm adding a dedicated m_ZeroInt() function and building m_Zero() from
that. In most cases, calling code can be updated to use m_ZeroInt()
directly when there's no need to match pointers, but I'm leaving that
efficiency optimization as a follow-up step because it's not always
clear when that's ok.
There are just enough icmp folds in InstSimplify that can be used for
integer or pointer types, that we probably still want a generic m_Zero()
for those cases. Otherwise, we could eliminate it (and possibly add a
m_NullPtr() as an alias for isa<ConstantPointerNull>()).
We're conservatively returning a full zero vector (zeroinitializer) in
InstSimplify/InstCombine on some of these folds (see diffs in InstSimplify),
but I'm not sure if that's actually necessary in all cases. We may be
able to propagate an undef lane instead. One test where this happens is
marked with 'TODO'.
llvm-svn: 330550
Summary:
When sinking an instruction in InstCombine we now also sink
the DbgInfoIntrinsics that are using the sunken value.
Example)
When sinking the load in this input
bb.X:
%0 = load i64, i64* %start, align 4, !dbg !31
tail call void @llvm.dbg.value(metadata i64 %0, ...)
br i1 %cond, label %for.end, label %for.body.lr.ph
for.body.lr.ph:
br label %for.body
we now also move the dbg.value, like this
bb.X:
br i1 %cond, label %for.end, label %for.body.lr.ph
for.body.lr.ph:
%0 = load i64, i64* %start, align 4, !dbg !31
tail call void @llvm.dbg.value(metadata i64 %0, ...)
br label %for.body
In the past we haven't moved the dbg.value so we got
bb.X:
tail call void @llvm.dbg.value(metadata i64 %0, ...)
br i1 %cond, label %for.end, label %for.body.lr.ph
for.body.lr.ph:
%0 = load i64, i64* %start, align 4, !dbg !31
br label %for.body
So in the past we got a debug-use before the def of %0.
And that dbg.value was also on the path jumping to %for.end, for
which %0 never was defined.
CodeGenPrepare normally comes to rescue later (when not moving
the dbg.value), since it moves dbg.value instrinsics quite
brutally, without really analysing if it is correct to move
the intrinsic (see PR31878).
So at the moment this patch isn't expected to have much impact,
besides that it is moving the dbg.value already in opt, making
the IR look more sane directly.
This can be seen as a preparation to (hopefully) make it possible
to turn off CodeGenPrepare::placeDbgValues later as a solution
to PR31878.
I also adjusted test/DebugInfo/X86/sdagsplit-1.ll to make the
IR in the test case up-to-date with this behavior in InstCombine.
Reviewers: rnk, vsk, aprantl
Reviewed By: vsk, aprantl
Subscribers: mattd, JDevlieghere, llvm-commits
Tags: #debug-info
Differential Revision: https://reviews.llvm.org/D45425
llvm-svn: 330243
The bitcast may be interfering with other combines or vectorization
as shown in PR16739:
https://bugs.llvm.org/show_bug.cgi?id=16739
Most pointer-related optimizations are probably able to look through
this bitcast, but removing the bitcast shrinks the IR, so it's at
least a size savings.
Differential Revision: https://reviews.llvm.org/D44833
llvm-svn: 330237
Two cleanups:
1. As noted in D45453, we had tests that don't need FMF that were misplaced in the 'fast-math.ll' test file.
2. This removes the final uses of dyn_castFNegVal, so that can be deleted. We use 'match' now.
llvm-svn: 330126
Summary:
In order to get the whole fold as specified in [[ https://bugs.llvm.org/show_bug.cgi?id=6773 | PR6773 ]],
let's first handle the simple straight-forward things.
Let's start with the `and` -> `or` simplification.
The one obvious thing missing here: the constant mask is not handled.
I have an idea how to handle it, but it will require some thinking,
and is not strictly required here, so i've left that for later.
https://rise4fun.com/Alive/Pkmg
Reviewers: spatel, craig.topper, eli.friedman, jingyue
Reviewed By: spatel
Subscribers: llvm-commits
Was reviewed as part of https://reviews.llvm.org/D45631
llvm-svn: 330103
These simplifications were previously enabled only with isFast(), but that
is more restrictive than required. Since r317488, FMF has 'reassoc' to
control these cases at a finer level.
llvm-svn: 330089
Summary:
The fold added in D45108 did not account for the fact that
the and instruction is commutative, and if the mask is a variable,
the mask variable and the fold variable may be swapped.
I have noticed this by accident when looking into [[ https://bugs.llvm.org/show_bug.cgi?id=6773 | PR6773 ]]
This extends/generalizes that fold, so it is handled too.
Reviewers: spatel, craig.topper
Reviewed By: spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45539
llvm-svn: 330001
This completes the work started in r329604 and r329605 when we changed clang to no longer use the intrinsics.
We lost some InstCombine SimplifyDemandedBit optimizations through this change as we aren't able to fold 'and', bitcast, shuffle very well.
llvm-svn: 329990
This restores what was lost with rL73243 but without
re-introducing the bug that was present in the old code.
Note that we already have these transforms if the ops are
marked 'fast' (and I assume that's happening somewhere in
the code added with rL170471), but we clearly don't need
all of 'fast' for these transforms.
llvm-svn: 329362
Summary:
This is a fix to PR37005.
Essentially, rL328539 ([InstCombine] reassociate loop invariant GEP chains to enable LICM) contains a bug
whereby it will convert:
%src = getelementptr inbounds i8, i8* %base, <2 x i64> %val
%res = getelementptr inbounds i8, <2 x i8*> %src, i64 %val2
into:
%src = getelementptr inbounds i8, i8* %base, i64 %val2
%res = getelementptr inbounds i8, <2 x i8*> %src, <2 x i64> %val
By swapping the index operands if the GEPs are in a loop, and %val is loop variant while %val2
is loop invariant.
This fix recreates new GEP instructions if the index operand swap would result in the type
of %src changing from vector to scalar, or vice versa.
Reviewers: sebpop, spatel
Reviewed By: sebpop
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45287
llvm-svn: 329331
The tests marked with 'FIXME' require loosening the check
in SimplifyAssociativeOrCommutative() to optimize completely;
that's still checking isFast() in Instruction::isAssociative().
llvm-svn: 329121
Summary:
Folding patterns like:
%vec = shufflevector <4 x i8> %insvec, <4 x i8> undef, <4 x i32> zeroinitializer
%cast = bitcast <4 x i8> %vec to i32
%cond = icmp eq i32 %cast, 0
into:
%ext = extractelement <4 x i8> %insvec, i32 0
%cond = icmp eq i32 %ext, 0
Combined with existing rules, this allows us to fold patterns like:
%insvec = insertelement <4 x i8> undef, i8 %val, i32 0
%vec = shufflevector <4 x i8> %insvec, <4 x i8> undef, <4 x i32> zeroinitializer
%cast = bitcast <4 x i8> %vec to i32
%cond = icmp eq i32 %cast, 0
into:
%cond = icmp eq i8 %val, 0
When we construct a splat vector via a shuffle, and bitcast the vector into an integer type for comparison against an integer constant. Then we can simplify the the comparison to compare the splatted value against the integer constant.
Reviewers: spatel, anna, mkazantsev
Reviewed By: spatel
Subscribers: efriedma, rengolin, llvm-commits
Differential Revision: https://reviews.llvm.org/D44997
llvm-svn: 329087
Summary:
The cast simplifications that instcombine does here do not make any
attempt to obey the verifier rules for musttail calls. Therefore we have
to disable them.
Reviewers: efriedma, majnemer, pcc
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D45186
llvm-svn: 329027
This change brings performance of zlib up by 10%. The example below is from a
hot loop in longest_match() from zlib.
do.body:
%cur_match.addr.0 = phi i32 [ %cur_match, %entry ], [ %2, %do.cond ]
%idx.ext = zext i32 %cur_match.addr.0 to i64
%add.ptr = getelementptr inbounds i8, i8* %win, i64 %idx.ext
%add.ptr2 = getelementptr inbounds i8, i8* %add.ptr, i64 %idx.ext1
%add.ptr3 = getelementptr inbounds i8, i8* %add.ptr2, i64 -1
In this example %idx.ext1 is a loop invariant. It will be moved above the use of
loop induction variable %idx.ext such that it can be hoisted out of the loop by
LICM. The operands that have dependences carried by the loop will be sinked down
in the GEP chain. This patch will produce the following output:
do.body:
%cur_match.addr.0 = phi i32 [ %cur_match, %entry ], [ %2, %do.cond ]
%idx.ext = zext i32 %cur_match.addr.0 to i64
%add.ptr = getelementptr inbounds i8, i8* %win, i64 %idx.ext1
%add.ptr2 = getelementptr inbounds i8, i8* %add.ptr, i64 -1
%add.ptr3 = getelementptr inbounds i8, i8* %add.ptr2, i64 %idx.ext
llvm-svn: 328539
This replaces a large chunk of code that was looking for compound
patterns that include these sub-patterns. Existing tests ensure that
all of the previous examples are still folded as expected.
We still need to loosen the FMF check.
llvm-svn: 328502
Remove #include of Transforms/Scalar.h from Transform/Utils to fix layering.
Transforms depends on Transforms/Utils, not the other way around. So
remove the header and the "createStripGCRelocatesPass" function
declaration (& definition) that is unused and motivated this dependency.
Move Transforms/Utils/Local.h into Analysis because it's used by
Analysis/MemoryBuiltins.cpp.
llvm-svn: 328165
This is complicated by -0.0 and nan. This is based on the DAG patterns
as shown in D44091. I'm hoping that we can just remove those DAG folds
and always rely on IR canonicalization to handle the matching to fabs.
We would still need to delete the broken code from DAGCombiner to fix
PR36600:
https://bugs.llvm.org/show_bug.cgi?id=36600
Differential Revision: https://reviews.llvm.org/D44550
llvm-svn: 327858
This was supposed to be an NFC refactoring that will eventually allow
eliminating the isFast() predicate, but there's a rare possibility
that we would pessimize the code as shown in the test case because
we failed to check 'hasOneUse()' properly. This version also removes
an inefficiency of the old code; we would look for:
(X * C) * C1 --> X * (C * C1)
...but that pattern is always handled by
SimplifyAssociativeOrCommutative().
llvm-svn: 327404
getNumUses is a linear time operation. It traverses the user linked list to the end and counts as it goes. Since we are only interested in small constant counts, we should use hasNUses or hasNUsesMore more that terminate the traversal as soon as it can provide the answer.
There are still two other locations in InstCombine, but changing those would force a rebase of D44266 which if accepted would remove them.
Differential Revision: https://reviews.llvm.org/D44398
llvm-svn: 327315
Most of the folds based on SelectPatternResult belong in InstSimplify rather than
InstCombine, so the helper code should be available to other passes/analysis.
llvm-svn: 326812
Summary:
Presently, InstCombiner::foldICmpWithCastAndCast() implicitly assumes that it is
only invoked with icmp instructions of integer type. If that assumption is broken,
and it is called with an icmp of vector type, then it fails (asserts/crashes).
This patch addresses the deficiency. It allows it to simplify
icmp (ptrtoint x), (ptrtoint/c) of vector type into a compare of the inputs,
much as is done when the type is integer.
Reviewers: apilipenko, fedor.sergeev, mkazantsev, anna
Reviewed By: anna
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D44063
llvm-svn: 326730
This patch teaches getMinimumFPType to support shrinking a vector of ConstantFPs. This should improve our ability to combine vector fptrunc with fp binops.
Differential Revision: https://reviews.llvm.org/D43774
llvm-svn: 326729
Instead of returning the smaller FP constant we now return the minimal Type the constant can fit into. We also return the Type of the input to any fp extends. The legality checks are then done on just the size of these Types. If we find something profitable we then emit FPTruncs in front of the smaller binop and assume those FPTruncs will be constant folded or combined with any ConstantFPs or fpextends.
Differential Revision: https://reviews.llvm.org/D44038
llvm-svn: 326617
The code was checking that all of the instructions in the
sequence are 'fast', but that's not necessary. The final
multiply is all that we need to check (tests adjusted).
The fmul doesn't need to be fully 'fast' either, but that
can be another patch.
llvm-svn: 326608
This is a retry of r326502 with updates to the reassociate
test file that I missed the first time.
@test15_reassoc in the supposed -reassociate test file
(except that it tests 2 other passes too...) shows that
there's no clear responsiblity for reassociation transforms.
Instcombine now gets that case, but only because the
constant values are identical. Otherwise, it would still
miss that pattern.
Reassociate doesn't get that case because it hasn't been
updated to use less than 'fast' FMF.
llvm-svn: 326513
I forgot that I added tests for 'reassoc' to -reassociate, but
suprisingly that file calls -instcombine too, so it is affected.
I'll update that file and try again.
llvm-svn: 326510
Currently this code's control flow very much assumes that there are no meaningful checks after determining that it's a ConstantFP. So whenever it wants to stop it just does "return V". But V is also the variable name it uses when it wants to return a new value. So 'return V' appears multiple times with different meanings.
This patch just moves all the code into a helper function and returns nullptr when it wants to stop.
I've split this from D43774 while I try to figure out how to best handle the vector case there. But this change by itself at least seemed like a readability improvement.
Differential Revision: https://reviews.llvm.org/D43833
llvm-svn: 326361
Also, rename 'foldOpWithConstantIntoOperand' because that's annoyingly
vague. The constant check is redundant in some cases, but it allows
removing duplication for most of the calls.
llvm-svn: 326329
Note: gcc appears to allow this fold with -freciprocal-math alone,
but clang/llvm require more than that with this patch. The wording
in the definitions seems fuzzy enough that it could go either way,
but we'll err on the conservative side of FMF interpretation.
This patch also changes the newly created fmul to have FMF propagated
by the last fdiv rather than intersecting the FMF of the fdivs. This
matches the behavior of other folds near here. The new fmul is only
used to produce an intermediate op for the final fdiv result, so it
shouldn't be any stricter than that result. The previous behavior
could result in dropping FMF via other folds in instcombine or CSE.
Differential Revision: https://reviews.llvm.org/D43398
llvm-svn: 326098
The existing code was inefficiently looking for 'nsz' variants.
That's unnecessary because we canonicalize those to the expected
form with -0.0.
We may also want to adjust or remove the fold that sinks negation.
We don't do that for fdiv (or integer ops?). That should be uniform?
It may also lead to missed optimization as in PR21914:
https://bugs.llvm.org/show_bug.cgi?id=21914
...or we just have to fix other passes to avoid that problem.
llvm-svn: 325924
These are fdiv-with-constant-divisor, so they already become
reciprocal multiplies. The last gap for vector ops should be
closed with rL325590.
It's possible that we're missing folds for some edge cases
with denormal intermediate constants after deleting these,
but there are no tests for those patterns, and it would be
better to handle denormals more consistently (and less
conservatively) as noted in TODO comments.
llvm-svn: 325595
It's possible that we could allow this either 'arcp' or 'reassoc' alone, but this
should be conservatively better than what we have right now. GCC allows this with
only -freciprocal-math.
The last test is changed to show a case that is expected to fold, but we need D43398.
llvm-svn: 325533
The last fold that used to be here was not necessary. That's a
combination of 2 folds (and there's a regression test to show that).
The transforms are guarded by isFast(), but that should be loosened.
llvm-svn: 325531
With this patch in place, when a new-format TBAA tag is available
for a memory-transfer intrinsic call, we prefer propagating that
new-format tag. Otherwise, we fallback to the old approach where
we try to construct a proper TBAA access tag from 'tbaa.struct'
metadata.
Differential Revision: https://reviews.llvm.org/D41543
llvm-svn: 325488
...and delete the equivalent local functiona from InstCombine.
These might be useful to other InstCombine files or other passes
and makes FP queries more similar to integer constant queries.
llvm-svn: 325398
Craig Topper