Add two levels of verification for MemorySSA: Fast and Full.
The defaults are kept the same. Full verification always occurs under
EXPENSIVE_CHECKS, but now it can also be requested in a specific pass for
debugging purposes.
This extends the reduction logic in the vectorizer to handle intrinsic
versions of min and max, both the floating point variants already
created by instcombine under fastmath and the integer variants from
D98152.
As a bonus this allows us to match a chain of min or max operations into
a single reduction, similar to how add/mul/etc work.
Differential Revision: https://reviews.llvm.org/D109645
Added '-print-pipeline-passes' printing of parameters for those passes
declared with *_WITH_PARAMS macro in PassRegistry.def.
Note that it only prints the parameters declared inside *_WITH_PARAMS as
in a few cases there appear to be additional parameters not parsable.
The following passes are now covered (i.e. all of those with *_WITH_PARAMS in
PassRegistry.def).
LoopExtractorPass - loop-extract
HWAddressSanitizerPass - hwsan
EarlyCSEPass - early-cse
EntryExitInstrumenterPass - ee-instrument
LowerMatrixIntrinsicsPass - lower-matrix-intrinsics
LoopUnrollPass - loop-unroll
AddressSanitizerPass - asan
MemorySanitizerPass - msan
SimplifyCFGPass - simplifycfg
LoopVectorizePass - loop-vectorize
MergedLoadStoreMotionPass - mldst-motion
GVN - gvn
StackLifetimePrinterPass - print<stack-lifetime>
SimpleLoopUnswitchPass - simple-loop-unswitch
Differential Revision: https://reviews.llvm.org/D109310
This fixes a violation of the wrap flag rules introduced in c4048d8f. As noted in the original review, the NUW is legal to infer from the structure of the replacee, but a) there's no test coverage, and b) this should be done generically for all multiplies.
Differential Revision: https://reviews.llvm.org/D109782
SCEV does not look through non-header PHIs inside the loop. Such phis
can be analyzed by adding separate accesses for each incoming pointer
value.
This results in 2 more loops vectorized in SPEC2000/186.crafty and
avoids regressions when sinking instructions before vectorizing.
Fixes PR50296, PR50288.
Reviewed By: Meinersbur
Differential Revision: https://reviews.llvm.org/D102266
This is for Swift VFE support. In some vtable forms that Swift emits, the "base" of a relative pointer is not the global symbol itself directly, but a GEP into it -- so the pointer is relative to a particular field in the global. So getPointerAtOffset() needs to be able to see through the GEP and allow it in a SUB expression, to correctly recognize the offset as a vtable slot.
Differential Revision: https://reviews.llvm.org/D109169
Pass the access type to getPtrStride(), so it is not determined
from the pointer element type. Many cases still fetch the element
type at a higher level though, so this only partially addresses
the issue.
This reapplies commit 7dbba3376f, or, put
differently, this reverts commit d9a8d20827.
The test now requires the amdgpu and nvptx backend explicitly as it
won't work without properly.
Not all address spaces support initializers for globals and we can
therefore not set them without checking if they are allowed. This
patch adds a hook into TTI to check if an AS allows non-undef
initializers. We disable it for all but address space 0 by default,
NVPTX and AMDGPU targets allow all but address space 3.
Reviewed By: tra
Differential Revision: https://reviews.llvm.org/D109337
It's possible in some cases for the LHS to be a pointer where the RHS is not. This isn't directly possible for an icmp, but the analysis mixes up operands of different icmp expressions in some cases.
This does not include a test case as the smallest reduced case we've managed is extremely fragile and unlikely to test anything meaningful in the long term.
Also add an assertion to getNotSCEV() to make tracking down this sort of issue a bit easier in the future.
Fixes https://bugs.llvm.org/show_bug.cgi?id=51787 .
Differential Revision: https://reviews.llvm.org/D109546
This bit of code is incredibly suspicious. It allows fully unknown (but potentially negative) steps, but not steps known to be negative. The comment about scev flag inference is worrying, but also not correct to my knowledge.
At best, this might be covering up some related miscompile. However, there's no test in tree for it, the review history doesn't include obvious motivation, and the C++ example doesn't appear to give wrong results when hand translated to IR. I think it's time to remove this and see what falls out.
During review, there were concerns raised about the correctness of the corresponding signed case. This change was deliberately narrowed to the unsigned case which has been auditted and appears correct for negative values. We need to get back to the known-negative signed case, but that'll be a future patch if nothing falls out from this one.
Differential Revision: https://reviews.llvm.org/D104140
In general, howManyLessThans doesn't really want to work with pointers
at all; the result is an integer, and the operands of the icmp are
effectively integers. However, isLoopEntryGuardedByCond doesn't like
extra ptrtoint casts, so the arguments to isLoopEntryGuardedByCond need
to be computed without those casts.
Somehow, the values got mixed up with the recent howManyLessThans
improvements; fix the confused values, and add a better comment to
explain what's happening.
Differential Revision: https://reviews.llvm.org/D109465
This renames the primary methods for creating a zero value to `getZero`
instead of `getNullValue` and renames predicates like `isAllOnesValue`
to simply `isAllOnes`. This achieves two things:
1) This starts standardizing predicates across the LLVM codebase,
following (in this case) ConstantInt. The word "Value" doesn't
convey anything of merit, and is missing in some of the other things.
2) Calling an integer "null" doesn't make any sense. The original sin
here is mine and I've regretted it for years. This moves us to calling
it "zero" instead, which is correct!
APInt is widely used and I don't think anyone is keen to take massive source
breakage on anything so core, at least not all in one go. As such, this
doesn't actually delete any entrypoints, it "soft deprecates" them with a
comment.
Included in this patch are changes to a bunch of the codebase, but there are
more. We should normalize SelectionDAG and other APIs as well, which would
make the API change more mechanical.
Differential Revision: https://reviews.llvm.org/D109483
We were returning a tuple when all but one caller only cared about one piece of the return value. That one caller can inline the complexity, and we can simplify all other uses.
Users of delinearization assume that the the offset into the array element is zero. In most cases it will indeed be zero, but if it is not, the delinearization has to fail since it violates that assumption without the API even allowing to signal to the caller that the by offset is non-zero.
This bug caused Polly to miscompile blender (526.blender_r from SPEC CPU 2017) in -polly-process-unprofitable mode. The SCEV expression incorrectly delinearized has been reduced in the test case byte_offset.ll. The dropped offset into the array element of size 4 (a float) is ((sext i32 %mul7.i4534 to i64) + {(sext i32 %i1 to i64),+,((sext i32 (1 + ((1 + %shl.i.i) * (1 + %shl.i.i)) + %shl.i.i) to i64) * (sext i32 %i1 to i64))}<%for.body703>). This significant component was just dropped, and the wrong pointer was computed when regenerating code from the remaining delinearized subscripts. This occurred during blender's subsurface scattering implementation. As a result, blender's rendering diverged from the reference image.
Patch D108885 would also fix the API.
Reviewed By: bmahjour
Differential Revision: https://reviews.llvm.org/D109133
The implementation is mostly copied from MemDepAnalysis. We want to look
at all loads and stores to the same pointer operand. Bitcasts and zero
GEPs of a pointer are considered the same pointer value. We choose the
most dominating instruction.
Since updating MemorySSA with invariant.group is non-trivial, for now
handling of invariant.group is not cached in any way, so it's part of
the walker. The number of loads/stores with invariant.group is small for
now anyway. We can revisit if this actually noticeably affects compile
times.
To avoid invariant.group affecting optimized uses, we need to have
optimizeUsesInBlock() not use invariant.group in any way.
Co-authored-by: Piotr Padlewski <prazek@google.com>
Reviewed By: asbirlea, nikic, Prazek
Differential Revision: https://reviews.llvm.org/D109134
None of this logic has anything to do with SCEV's internals, it just uses the existing public APIs. As a result, we can move the code from ScalarEvolution.cpp/hpp to Delinearization.cpp/hpp with only minor changes.
This was discussed in advance on today's loop opt call. It turned out to be easy as hoped.
The basic problem being solved is that we largely give up when encountering a trip count involving an IV which is not an addrec. We will fall back to the brute force constant eval, but that doesn't have the information about the fact that we can't cycle back through the same set of values.
There's a high level design question of whether this is the right place to handle this, and if not, where that place is. The major alternative here would be to return a conservative upper bound, and then rely on two invocations of indvars to add the facts to the narrow IV, and then reconstruct SCEV. (I have not implemented the alternative and am not 100% sure this would work out.) That's arguably more in line with existing code, but I find this substantially easier to reason about. During review, no one expressed a strong opinion, so we went with this one.
Differential Revision: D108651
Follow on to D109029. I realized we had no mention of mustprogrress in the comment (as it prexisted mustprogress in the codebase). In the process of adding it, I tweaked the preconditions into something I think is more clear. Note that mustprogress is checked in the code.
Differential Revision: https://reviews.llvm.org/D109091
Support opaque pointers in SymbolicallyEvaluateGEP() by using the
value type of a GlobalValue base or falling back to i8 if there
isn't one. We don't unconditionally generate i8 GEPs here because
that would lose inrange attribues, and because some optimizations
on globals currently rely on GEP types (e.g. the globals SROA
mentioned in the comment).
Differential Revision: https://reviews.llvm.org/D109297
Due to a typo, this replaced %x with umax(C1, umin(C2, %x + C3))
rather than umax(C1, umin(C2, %x)). This didn't make a difference
for the existing tests, because the result is only used for range
calculation, and %x will usually have an unknown starting range,
and the additional offset keeps it unknown. However, if %x already
has a known range, we may compute a result range that is too
small.
The current IRSimilarityIdentifier does not try to find similarity across blocks, this patch provides a mechanism to compare two branches against one another, to find similarity across basic blocks, rather than just within them.
This adds a step in the similarity identification process that labels all of the basic blocks so that we can identify the relative branching locations. Within an IRSimilarityCandidate we use these relative locations to determine whether if the branching to other relative locations in the same region is the same between branches. If they are, we consider them similar.
We do not consider the relative location of the branch if the target branch is outside of the region. In this case, both branches must exit to a location outside the region, but the exact relative location does not matter.
Reviewers: paquette, yroux
Differential Revision: https://reviews.llvm.org/D106989
If the vector is a splat of some scalar value, findScalarElement()
can simply return the scalar value if it knows the requested lane
is in the vector.
This is only needed for scalable vectors, because the InsertElement/ShuffleVector
case is already handled explicitly for the fixed-width case.
This helps to recognize an InstCombine fold like:
extractelt(bitcast(splat(%v))) -> bitcast(%v)
Reviewed By: spatel
Differential Revision: https://reviews.llvm.org/D107254
Recommit of 707ce34b06. Don't introduce a
dependency to the LLVMPasses component, instead register the required
passes individually.
Add methods for loop unrolling to the OpenMPIRBuilder class and use them in Clang if `-fopenmp-enable-irbuilder` is enabled. The unrolling methods are:
* `unrollLoopFull`
* `unrollLoopPartial`
* `unrollLoopHeuristic`
`unrollLoopPartial` and `unrollLoopHeuristic` can use compiler heuristics to automatically determine the unroll factor. If possible, that is if no CanonicalLoopInfo is required to pass to another method, metadata for LLVM's LoopUnrollPass is added. Otherwise the unroll factor is determined using the same heurstics as user by LoopUnrollPass. Not requiring a CanonicalLoopInfo, especially with `unrollLoopHeuristic` allows greater flexibility.
With full unrolling and partial unrolling with known unroll factor, instead of duplicating instructions by the OpenMPIRBuilder, the full unroll is still delegated to the LoopUnrollPass. In case of partial unrolling the loop is first tiled using the existing `tileLoops` methods, then the inner loop fully unrolled using the same mechanism.
Reviewed By: jdoerfert, kiranchandramohan
Differential Revision: https://reviews.llvm.org/D107764
When preinliner is used for CSSPGO, we try to honor global preinliner decision as much as we can except for uninlinable callees. We rely on InlineCost::Never to prevent us from illegal inlining.
However, it turns out that we use InlineCost::Never for both illeagle inlining and some of the "not-so-beneficial" inlining.
The most common one is recursive inlining, while it can bloat size a lot during CGSCC bottom-up inlining, it's less of a problem when recursive inlining is guided by profile and done in top-down manner.
Ideally it'd be better to have a clear separation between inline legality check vs cost-benefit check, but that requires a bigger change.
This change enables InlineCost computation to allow inlining recursive calls, controlled by InlineParams. In SampleLoader, we now enable recursive inlining for CSSPGO when global preinliner decision is used.
With this change, we saw a few perf improvements on SPEC2017 with CSSPGO and preinliner on: 2% for povray_r, 6% for xalancbmk_s, 3% omnetpp_s, while size is about the same (no noticeable perf change for all other benchmarks)
Differential Revision: https://reviews.llvm.org/D109104
This patch introduces four new string attributes: function-inline-cost,
function-inline-threshold, call-inline-cost and call-threshold-bonus.
These attributes allow you to selectively override some aspects of
InlineCost analysis. That would allow us to test inliner separately from
the InlineCost analysis.
That could be useful when you're trying to write tests for inliner and
you need to test some very specific situation, like "the inline cost has
to be this high", or "the threshold has to be this low". Right now every
time someone does that, they have get creative to come up with a way to
make the InlineCost give them the number they need (like adding ~30
load/add pairs for a trivial test). This process can be somewhat tedious
which can discourage some people from writing enough tests for their
changes. Also, that results in tests that are fragile and can be easily
broken without anyone noticing it because the test writer can't
explicitly control what input the inliner will get from the inline cost
analysis.
These new attributes will alleviate those problems to an extent.
Reviewed By: mtrofin
Differential Revision: https://reviews.llvm.org/D109033
Please refer to
https://lists.llvm.org/pipermail/llvm-dev/2021-September/152440.html
(and that whole thread.)
TLDR: the original patch had no prior RFC, yet it had some changes that
really need a proper RFC discussion. It won't be productive to discuss
such an RFC, once it's actually posted, while said patch is already
committed, because that introduces bias towards already-committed stuff,
and the tree is potentially in broken state meanwhile.
While the end result of discussion may lead back to the current design,
it may also not lead to the current design.
Therefore i take it upon myself
to revert the tree back to last known good state.
This reverts commit 4c4093e6e3.
This reverts commit 0a2b1ba33a.
This reverts commit d9873711cb.
This reverts commit 791006fb8c.
This reverts commit c22b64ef66.
This reverts commit 72ebcd3198.
This reverts commit 5fa6039a5f.
This reverts commit 9efda541bf.
This reverts commit 94d3ff09cf.
Breaks build with -DBUILD_SHARED_LIBS=ON
```
CMake Error: The inter-target dependency graph contains the following strongly connected component (cycle):
"LLVMFrontendOpenMP" of type SHARED_LIBRARY
depends on "LLVMPasses" (weak)
"LLVMipo" of type SHARED_LIBRARY
depends on "LLVMFrontendOpenMP" (weak)
"LLVMCoroutines" of type SHARED_LIBRARY
depends on "LLVMipo" (weak)
"LLVMPasses" of type SHARED_LIBRARY
depends on "LLVMCoroutines" (weak)
depends on "LLVMipo" (weak)
At least one of these targets is not a STATIC_LIBRARY. Cyclic dependencies are allowed only among static libraries.
CMake Generate step failed. Build files cannot be regenerated correctly.
```
This reverts commit 707ce34b06.
Add methods for loop unrolling to the OpenMPIRBuilder class and use them in Clang if `-fopenmp-enable-irbuilder` is enabled. The unrolling methods are:
* `unrollLoopFull`
* `unrollLoopPartial`
* `unrollLoopHeuristic`
`unrollLoopPartial` and `unrollLoopHeuristic` can use compiler heuristics to automatically determine the unroll factor. If possible, that is if no CanonicalLoopInfo is required to pass to another method, metadata for LLVM's LoopUnrollPass is added. Otherwise the unroll factor is determined using the same heurstics as user by LoopUnrollPass. Not requiring a CanonicalLoopInfo, especially with `unrollLoopHeuristic` allows greater flexibility.
With full unrolling and partial unrolling with known unroll factor, instead of duplicating instructions by the OpenMPIRBuilder, the full unroll is still delegated to the LoopUnrollPass. In case of partial unrolling the loop is first tiled using the existing `tileLoops` methods, then the inner loop fully unrolled using the same mechanism.
Reviewed By: jdoerfert, kiranchandramohan
Differential Revision: https://reviews.llvm.org/D107764
There's a silent bug in our reasoning about zero strides. We assume that having a single static exit implies that if that exit is not taken, then the loop must be infinite. This ignores the potential for abnormal exits via exceptions. Consider the following example:
for (uint_8 i = 0; i < 1; i += 0) {
throw_on_thousandth_call();
}
Our reasoning is such that we'd conclude this loop can't take the backedge as that would lead to a (presumed) infinite loop.
In practice, this is a silent bug because the loopIsFiniteByAssumption returns false strictly more often than the loopHaNoAbnormalExits property. We could reasonable want to change that in the future, so fixing the codeflow now is worthwhile.
Differential Revision: https://reviews.llvm.org/D109029
Store the used element type in the InductionDescriptor. For typed
pointers, it remains the pointer element type. For opaque pointers,
we always use an i8 element type, such that the step is a simple
offset.
A previous version of this patch instead tried to guess the element
type from an induction GEP, but this is not reliable, as the GEP
may be hidden (see @both in iv_outside_user.ll).
Differential Revision: https://reviews.llvm.org/D104795
This extends D108921 into a generic rule applied to constructing ExitLimits along all paths. The remaining paths (primarily howFarToZero) don't have the same reasoning about UB sensitivity as the howManyLessThan ones did. Instead, the remain cause for max counts being more precise than exact counts is that we apply context sensitive loop guards on the max path, and not on the exact path. That choice is mildly suspect, but out of scope of this patch.
The MVETailPredication.cpp change deserves a bit of explanation. We were previously figuring out that two SCEVs happened to be equal because the happened to be identical. When we optimized one with context sensitive information, but not the other, we lost the ability to prove them equal. So, cover this case by subtracting and then applying loop guards again. Without this, we see changes in test/CodeGen/Thumb2/mve-blockplacement.ll
Differential Revision: https://reviews.llvm.org/D109015
This patch is specifically the howManyLessThan case. There will be a couple of followon patches for other codepaths.
The subtle bit is explaining why the two codepaths have a difference while both are correct. The test case with modifications is a good example, so let's discuss in terms of it.
* The previous exact bounds for this example of (-126 + (126 smax %n))<nsw> can evaluate to either 0 or 1. Both are "correct" results, but only one of them results in a well defined loop. If %n were 127 (the only possible value producing a trip count of 1), then the loop must execute undefined behavior. As a result, we can ignore the TC computed when %n is 127. All other values produce 0.
* The max taken count computation uses the limit (i.e. the maximum value END can be without resulting in UB) to restrict the bound computation. As a result, it returns 0 which is also correct.
WARNING: The logic above only holds for a single exit loop. The current logic for max trip count would be incorrect for multiple exit loops, except that we never call computeMaxBECountForLT except when we can prove either a) no overflow occurs in this IV before exit, or b) this is the sole exit.
An alternate approach here would be to add the limit logic to the symbolic path. I haven't played with this extensively, but I'm hesitant because a) the term is optional and b) I'm not sure it'll reliably simplify away. As such, the resulting code quality from expansion might actually get worse.
This was noticed while trying to figure out why D108848 wasn't NFC, but is otherwise standalone.
Differential Revision: https://reviews.llvm.org/D108921
To support Virtual Function Elimination to Swift, this PR adds support for Swift
vtables which contain "relative pointers" instead of direct pointer references.
These are in the form of:
@symbol = ... {
i32 trunc (i64 sub (i64 ptrtoint (<type> @target to i64), i64 ptrtoint (... @symbol to i64)) to i32)
}
The PR extends GlobalDCE's way of looking up a vtable offset into a dependency
to be able to see through this expression and find the target symbol.
Differential Revision: https://reviews.llvm.org/D107645
ExposePointerBase() in SCEVExpander implements basically the same
functionality as removePointerBase() in SCEV, so reuse it.
The SCEVExpander code assumes that the pointer operand on adds is
the last one -- I'm not sure that always holds. As such this might
not be strictly NFC.
When the initial relationship between two pairs of values between
similar sections is ambiguous to commutativity, arguments to the
outlined functions can be passed in such that the order is incorrect,
causing miscompilations. This adds a canonical mapping to each
similarity section, so that we can maintain the relationship of global
value numbering from one section to another.
Added Tests:
Transforms/IROutliner/outlining-commutative-operands-opposite-order.ll
unittests/Analysis/IRSimilarityIdentifierTest.cpp - IRSimilarityCandidate:CanonicalNumbering
Reviewers: jroelofs, jpaquette, yroux
Differential Revision: https://reviews.llvm.org/D104143
This was previously committed in 914836b, and reverted due to confusion on the status of the review.
Differential Revision: https://reviews.llvm.org/D108601
These are similar to the rotate pattern added with:
dcf659e821
...but we don't have guard ops on the shift amount,
so we don't canonicalize to the intrinsic.
declare void @llvm.assume(i1)
define i32 @src(i32 %shamt, i32 %bitwidth) {
; subtract must be in range of bitwidth
%lt = icmp ule i32 %bitwidth, 32
call void @llvm.assume(i1 %lt)
%r = lshr i32 -1, %shamt
%s = sub i32 %bitwidth, %shamt
%l = shl i32 -1, %s
%o = or i32 %r, %l
ret i32 %o
}
define i32 @tgt(i32 %shamt, i32 %bitwidth) {
ret i32 -1
}
https://alive2.llvm.org/ce/z/aF7WHx
If we no an addrec doesn't self-wrap, the increment is strictly positive, and the start value is the smallest representable value, then we know that the corresponding wrap type can not occur.
Differential Revision: https://reviews.llvm.org/D108601
When using final reward (which is now the default), we were skipping
logging decisions that were leading to callee deletion. This fixes that.
Differential Revision: https://reviews.llvm.org/D108587
Because of an odd linking problem, we need to temporarily support
building with TF C API 1.15 + tensorflow 2.50 pip package in
'development' mode scenarios. Protobuf Message 'Swap' is partially
implemented in the header (2.50) and relies on a symbol not found in TF
C API 1.15. std::move avoids that, at no semantic cost.
This reverts commit f4122398e7 to
investigate a crash exposed by it.
The patch breaks building the code below with `clang -O2 --target=aarch64-linux`
int a;
double b, c;
void d() {
for (; a; a++) {
b += c;
c = a;
}
}
This was probably bugging more than is reasonable, but it makes merging
changes in this file slightly less annoying to have the trailing comma
here. I only noticed this because Rust is currently carrying a patch to
this file and it kept making life a little difficult.
I have added a new TTI interface called enableOrderedReductions() that
controls whether or not ordered reductions should be enabled for a
given target. By default this returns false, whereas for AArch64 it
returns true and we rely upon the cost model to make sensible
vectorisation choices. It is still possible to override the new TTI
interface by setting the command line flag:
-force-ordered-reductions=true|false
I have added a new RUN line to show that we use ordered reductions by
default for SVE and Neon:
Transforms/LoopVectorize/AArch64/strict-fadd.ll
Transforms/LoopVectorize/AArch64/scalable-strict-fadd.ll
Differential Revision: https://reviews.llvm.org/D106653
According to the langref, it is valid to have multiple consecutive
lifetime start or end intrinsics on the same object.
For llvm.lifetime.start:
"If ptr [...] is a stack object that is already alive, it simply
fills all bytes of the object with poison."
For llvm.lifetime.end:
"Calling llvm.lifetime.end on an already dead alloca is no-op."
However, we currently fail an assertion in such cases. I've observed
the assertion failure when the loop vectorization pass duplicates
the intrinsic.
We can conservatively handle these intrinsics by ignoring all but
the first one, which can be implemented by removing the assertions.
Differential Revision: https://reviews.llvm.org/D108337
Nest from being perfect
Expand LoopNestAnalysis to return the full list of instructions that
cause a loop nest to be imperfect. This is useful for other passes to
know if they should continue for in the inner loops.
Added New function getInterveningInstructions
that returns a small vector with the instructions that prevent a loop
for being perfect. Also added a couple of helper functions to reduce
code duplication.
Reviewed By: Whitney
Differential Revision: https://reviews.llvm.org/D107773
This option has been enabled by default for quite a while now.
The practical impact of removing the option is that MSSA use
cannot be disabled in default pipelines (both LPM and NPM) and
in manual LPM invocations. NPM can still choose to enable/disable
MSSA using loop vs loop-mssa.
The next step will be to require MSSA for LICM and drop the
AST-based implementation entirely.
Differential Revision: https://reviews.llvm.org/D108075
Since then, the SCEV pointer handling as been improved,
so the assertion should now hold.
This reverts commit b96114c1e1,
relanding the assertion from commit 141e845da5.
Some files still contained the old University of Illinois Open Source
Licence header. This patch replaces that with the Apache 2 with LLVM
Exception licence.
Differential Revision: https://reviews.llvm.org/D107528
Clang diagnostics refer to identifier names in quotes.
This patch makes inline remarks conform to the convention.
New behavior:
```
% clang -O2 -Rpass=inline -Rpass-missed=inline -S a.c
a.c:4:25: remark: 'foo' inlined into 'bar' with (cost=-30, threshold=337) at callsite bar:0:25; [-Rpass=inline]
int bar(int a) { return foo(a); }
^
```
Reviewed By: hoy
Differential Revision: https://reviews.llvm.org/D107791
This is already done within InstCombine:
https://alive2.llvm.org/ce/z/MiGE22
...but leaving it out of analysis makes it
harder to avoid infinite loops there.
This is already done within InstCombine:
https://alive2.llvm.org/ce/z/MiGE22
...but leaving it out of analysis makes it
harder to avoid infinite loops there.
Teach LV to use masked-store to support interleave-store-group with
gaps (instead of scatters/scalarization).
The symmetric case of using masked-load to support
interleaved-load-group with gaps was introduced a while ago, by
https://reviews.llvm.org/D53668; This patch completes the store-scenario
leftover from D53668, and solves PR50566.
Reviewed by: Ayal Zaks
Differential Revision: https://reviews.llvm.org/D104750
fix an assertion due to mismatch type for Numerator and CacheLineSize in loop cache analysis pass.
Reviewed By: bmahjour
Differential Revision: https://reviews.llvm.org/D107618
1) add some self-diagnosis (when asserts are enabled) to check that all
features have the same nr of entries
2) avoid storing pointers to mutable fields because the proto API
contract doesn't actually guarantee those stay fixed even if no further
mutation of the object occurs.
Differential Revision: https://reviews.llvm.org/D107594
This is recommit of the patch 16ff91ebcc,
reverted in 0c28a7c990 because it had
an error in call of getFastMathFlags (base type should be FPMathOperator
but not Instruction). The original commit message is duplicated below:
Clang has builtin function '__builtin_isnan', which implements C
library function 'isnan'. This function now is implemented entirely in
clang codegen, which expands the function into set of IR operations.
There are three mechanisms by which the expansion can be made.
* The most common mechanism is using an unordered comparison made by
instruction 'fcmp uno'. This simple solution is target-independent
and works well in most cases. It however is not suitable if floating
point exceptions are tracked. Corresponding IEEE 754 operation and C
function must never raise FP exception, even if the argument is a
signaling NaN. Compare instructions usually does not have such
property, they raise 'invalid' exception in such case. So this
mechanism is unsuitable when exception behavior is strict. In
particular it could result in unexpected trapping if argument is SNaN.
* Another solution was implemented in https://reviews.llvm.org/D95948.
It is used in the cases when raising FP exceptions by 'isnan' is not
allowed. This solution implements 'isnan' using integer operations.
It solves the problem of exceptions, but offers one solution for all
targets, however some can do the check in more efficient way.
* Solution implemented by https://reviews.llvm.org/D96568 introduced a
hook 'clang::TargetCodeGenInfo::testFPKind', which injects target
specific code into IR. Now only SystemZ implements this hook and it
generates a call to target specific intrinsic function.
Although these mechanisms allow to implement 'isnan' with enough
efficiency, expanding 'isnan' in clang has drawbacks:
* The operation 'isnan' is hidden behind generic integer operations or
target-specific intrinsics. It complicates analysis and can prevent
some optimizations.
* IR can be created by tools other than clang, in this case treatment
of 'isnan' has to be duplicated in that tool.
Another issue with the current implementation of 'isnan' comes from the
use of options '-ffast-math' or '-fno-honor-nans'. If such option is
specified, 'fcmp uno' may be optimized to 'false'. It is valid
optimization in general, but it results in 'isnan' always returning
'false'. For example, in some libc++ implementations the following code
returns 'false':
std::isnan(std::numeric_limits<float>::quiet_NaN())
The options '-ffast-math' and '-fno-honor-nans' imply that FP operation
operands are never NaNs. This assumption however should not be applied
to the functions that check FP number properties, including 'isnan'. If
such function returns expected result instead of actually making
checks, it becomes useless in many cases. The option '-ffast-math' is
often used for performance critical code, as it can speed up execution
by the expense of manual treatment of corner cases. If 'isnan' returns
assumed result, a user cannot use it in the manual treatment of NaNs
and has to invent replacements, like making the check using integer
operations. There is a discussion in https://reviews.llvm.org/D18513#387418,
which also expresses the opinion, that limitations imposed by
'-ffast-math' should be applied only to 'math' functions but not to
'tests'.
To overcome these drawbacks, this change introduces a new IR intrinsic
function 'llvm.isnan', which realizes the check as specified by IEEE-754
and C standards in target-agnostic way. During IR transformations it
does not undergo undesirable optimizations. It reaches instruction
selection, where is lowered in target-dependent way. The lowering can
vary depending on options like '-ffast-math' or '-ffp-model' so the
resulting code satisfies requested semantics.
Differential Revision: https://reviews.llvm.org/D104854
Before D45736, getc_unlocked was available by default, but turned off
for non-Cygwin/non-MinGW Windows. D45736 then added 9 more unlocked
functions, which were unavailable by default, but it also:
* left getc_unlocked enabled by default,
* removed the disabling line for Windows, and
* added code to enable getc_unlocked for GNU, Android, and OSX.
For consistency, make getc_unlocked unavailable by default. Maybe this
was the intent of D45736 anyway.
Reviewed By: MaskRay, efriedma
Differential Revision: https://reviews.llvm.org/D107527
Function exploreDirections() in DependenceAnalysis implements a recursive
algorithm for refining direction vectors. This algorithm has worst-case
complexity of O(3^(n+1)) where n is the number of common loop levels.
In this patch I'm adding a threshold to control the amount of time we
spend in doing MIV tests (which most of the time end up resulting in over
pessimistic direction vectors anyway).
Reviewed By: Meinersbur
Differential Revision: https://reviews.llvm.org/D107159
These functions don't exist in android API levels < 21. A change in
llvm-12 (rG6dbf0cfcf789) caused Oz builds to emit this symbol assuming
it's available and thus is causing link errors. Simply disable it here.
Differential Revision: https://reviews.llvm.org/D107509
Clang has builtin function '__builtin_isnan', which implements C
library function 'isnan'. This function now is implemented entirely in
clang codegen, which expands the function into set of IR operations.
There are three mechanisms by which the expansion can be made.
* The most common mechanism is using an unordered comparison made by
instruction 'fcmp uno'. This simple solution is target-independent
and works well in most cases. It however is not suitable if floating
point exceptions are tracked. Corresponding IEEE 754 operation and C
function must never raise FP exception, even if the argument is a
signaling NaN. Compare instructions usually does not have such
property, they raise 'invalid' exception in such case. So this
mechanism is unsuitable when exception behavior is strict. In
particular it could result in unexpected trapping if argument is SNaN.
* Another solution was implemented in https://reviews.llvm.org/D95948.
It is used in the cases when raising FP exceptions by 'isnan' is not
allowed. This solution implements 'isnan' using integer operations.
It solves the problem of exceptions, but offers one solution for all
targets, however some can do the check in more efficient way.
* Solution implemented by https://reviews.llvm.org/D96568 introduced a
hook 'clang::TargetCodeGenInfo::testFPKind', which injects target
specific code into IR. Now only SystemZ implements this hook and it
generates a call to target specific intrinsic function.
Although these mechanisms allow to implement 'isnan' with enough
efficiency, expanding 'isnan' in clang has drawbacks:
* The operation 'isnan' is hidden behind generic integer operations or
target-specific intrinsics. It complicates analysis and can prevent
some optimizations.
* IR can be created by tools other than clang, in this case treatment
of 'isnan' has to be duplicated in that tool.
Another issue with the current implementation of 'isnan' comes from the
use of options '-ffast-math' or '-fno-honor-nans'. If such option is
specified, 'fcmp uno' may be optimized to 'false'. It is valid
optimization in general, but it results in 'isnan' always returning
'false'. For example, in some libc++ implementations the following code
returns 'false':
std::isnan(std::numeric_limits<float>::quiet_NaN())
The options '-ffast-math' and '-fno-honor-nans' imply that FP operation
operands are never NaNs. This assumption however should not be applied
to the functions that check FP number properties, including 'isnan'. If
such function returns expected result instead of actually making
checks, it becomes useless in many cases. The option '-ffast-math' is
often used for performance critical code, as it can speed up execution
by the expense of manual treatment of corner cases. If 'isnan' returns
assumed result, a user cannot use it in the manual treatment of NaNs
and has to invent replacements, like making the check using integer
operations. There is a discussion in https://reviews.llvm.org/D18513#387418,
which also expresses the opinion, that limitations imposed by
'-ffast-math' should be applied only to 'math' functions but not to
'tests'.
To overcome these drawbacks, this change introduces a new IR intrinsic
function 'llvm.isnan', which realizes the check as specified by IEEE-754
and C standards in target-agnostic way. During IR transformations it
does not undergo undesirable optimizations. It reaches instruction
selection, where is lowered in target-dependent way. The lowering can
vary depending on options like '-ffast-math' or '-ffp-model' so the
resulting code satisfies requested semantics.
Differential Revision: https://reviews.llvm.org/D104854
Kazu Hirata