Also, rename recognizeBitReverseOrBSwapIdiom to recognizeBSwapOrBitReverseIdiom,
so the ordering of the MatchBSwaps and MatchBitReversals arguments are
consistent with the function name.
llvm-svn: 270715
Given that we're not actually reducing the instruction count in the included
regression tests, I think we would call this a canonicalization step.
The motivation comes from the example in PR26702:
https://llvm.org/bugs/show_bug.cgi?id=26702
If we hoist the bitwise logic ahead of the bitcast, the previously unoptimizable
example of:
define <4 x i32> @is_negative(<4 x i32> %x) {
%lobit = ashr <4 x i32> %x, <i32 31, i32 31, i32 31, i32 31>
%not = xor <4 x i32> %lobit, <i32 -1, i32 -1, i32 -1, i32 -1>
%bc = bitcast <4 x i32> %not to <2 x i64>
%notnot = xor <2 x i64> %bc, <i64 -1, i64 -1>
%bc2 = bitcast <2 x i64> %notnot to <4 x i32>
ret <4 x i32> %bc2
}
Simplifies to the expected:
define <4 x i32> @is_negative(<4 x i32> %x) {
%lobit = ashr <4 x i32> %x, <i32 31, i32 31, i32 31, i32 31>
ret <4 x i32> %lobit
}
Differential Revision: http://reviews.llvm.org/D17583
llvm-svn: 262645
This is part of the payoff for the refactoring in:
http://reviews.llvm.org/rL261649http://reviews.llvm.org/rL261707
In addition to removing a pile of duplicated code, the xor case was
missing the optimization for vector types because it checked
"SrcTy->isIntegerTy()" rather than "SrcTy->isIntOrIntVectorTy()"
like 'and' and 'or' were already doing.
This solves part of:
https://llvm.org/bugs/show_bug.cgi?id=26702
llvm-svn: 261750
Note: The 'and' case in foldCastedBitwiseLogic() is inheriting one extra
check from the nearly identical 'or' case:
if ((!isa<ICmpInst>(Cast0Src) || !isa<ICmpInst>(Cast1Src))
But I'm not sure how to expose that difference in a regression test.
Without that check, the 'or' path will infinite loop on:
test/Transforms/InstCombine/zext-or-icmp.ll
because the zext-or-icmp fold is attempting a reverse transform.
The refactoring should extend to the 'xor' case next to solve part of
PR26702.
llvm-svn: 261707
This is a straight cut and paste of the existing code and is intended to
be the first step in solving part of PR26702:
https://llvm.org/bugs/show_bug.cgi?id=26702
We should be able to reuse most of this and delete the nearly identical
existing code in visitOr(). Then, we can enhance visitXor() to use the
same code too.
llvm-svn: 261649
There are several requirements that ended up with this design;
1. Matching bitreversals is too heavyweight for InstCombine and doesn't really need to be done so early.
2. Bitreversals and byteswaps are very related in their matching logic.
3. We want to implement support for matching more advanced bswap/bitreverse patterns like partial bswaps/bitreverses.
4. Bswaps are best matched early in InstCombine.
The result of these is that a new utility function is created in Transforms/Utils/Local.h that can be configured to search for bswaps, bitreverses or both. InstCombine uses it to find only bswaps, CGP uses it to find only bitreversals.
We can then extend the matching logic in one place only.
llvm-svn: 257875
MatchBSwap has most of the functionality to match bit reversals already. If we switch it from looking at bytes to individual bits and remove a few early exits, we can extend the main recursive function to match any sequence of ORs, ANDs and shifts that assemble a value from different parts of another, base value. Once we have this bit->bit mapping, we can very simply detect if it is appropriate for a bswap or bitreverse.
llvm-svn: 255334
This is a partial fix for PR24886:
https://llvm.org/bugs/show_bug.cgi?id=24886
Without this IR transform, the backend (x86 at least) was producing inefficient code.
This patch is making 2 assumptions:
1. The canonical form of a fabs() operation is, in fact, the LLVM fabs() intrinsic.
2. The high bit of an FP value is always the sign bit; as noted in the bug report, this isn't specified by the LangRef.
Differential Revision: http://reviews.llvm.org/D13076
llvm-svn: 249702
This is a fix for PR22723:
https://llvm.org/bugs/show_bug.cgi?id=22723
My first attempt at this was to change what I thought was the root problem:
xor (zext i1 X to i32), 1 --> zext (xor i1 X, true) to i32
...but we create the opposite pattern in InstCombiner::visitZExt(), so infinite loop!
My next idea was to fix the matchIfNot() implementation in PatternMatch, but that would
mean potentially returning a different size for the match than what was input. I think
this would require all users of m_Not to check the size of the returned match, so I
abandoned that idea.
I settled on just fixing the exact case presented in the PR. This patch does allow the
2 functions in PR22723 to compile identically (x86):
bool test(bool x, bool y) { return !x | !y; }
bool test(bool x, bool y) { return !x || !y; }
...
andb %sil, %dil
xorb $1, %dil
movb %dil, %al
retq
Differential Revision: http://reviews.llvm.org/D12705
llvm-svn: 248634
Summary: We know that -x & 1 is equivalent to x & 1, avoid using negation for testing if a negative integer is even or odd.
Reviewers: majnemer
Subscribers: junbuml, mssimpso, gberry, mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D12156
llvm-svn: 245569
Summary:
This change splits `makeICmpRegion` into `makeAllowedICmpRegion` and
`makeSatisfyingICmpRegion` with slightly different contracts. The first
one is useful for determining what values some expression //may// take,
given that a certain `icmp` evaluates to true. The second one is useful
for determining what values are guaranteed to //satisfy// a given
`icmp`.
Reviewers: nlewycky
Reviewed By: nlewycky
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D8345
llvm-svn: 232575
Summary:
Now that the DataLayout is a mandatory part of the module, let's start
cleaning the codebase. This patch is a first attempt at doing that.
This patch is not exactly NFC as for instance some places were passing
a nullptr instead of the DataLayout, possibly just because there was a
default value on the DataLayout argument to many functions in the API.
Even though it is not purely NFC, there is no change in the
validation.
I turned as many pointer to DataLayout to references, this helped
figuring out all the places where a nullptr could come up.
I had initially a local version of this patch broken into over 30
independant, commits but some later commit were cleaning the API and
touching part of the code modified in the previous commits, so it
seemed cleaner without the intermediate state.
Test Plan:
Reviewers: echristo
Subscribers: llvm-commits
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 231740
This case is interesting because ScalarEvolutionExpander lowers min(a,
b) as ~max(~a,~b). I think the profitability heuristics can be made
more clever/aggressive, but this is a start.
Differential Revision: http://reviews.llvm.org/D7821
llvm-svn: 230285
creating a non-internal header file for the InstCombine pass.
I thought about calling this InstCombiner.h or in some way more clearly
associating it with the InstCombiner clas that it is primarily defining,
but there are several other utility interfaces defined within this for
InstCombine. If, in the course of refactoring, those end up moving
elsewhere or going away, it might make more sense to make this the
combiner's header alone.
Naturally, this is a bikeshed to a certain degree, so feel free to lobby
for a different shade of paint if this name just doesn't suit you.
llvm-svn: 226783
a cache of assumptions for a single function, and an immutable pass that
manages those caches.
The motivation for this change is two fold. Immutable analyses are
really hacks around the current pass manager design and don't exist in
the new design. This is usually OK, but it requires that the core logic
of an immutable pass be reasonably partitioned off from the pass logic.
This change does precisely that. As a consequence it also paves the way
for the *many* utility functions that deal in the assumptions to live in
both pass manager worlds by creating an separate non-pass object with
its own independent API that they all rely on. Now, the only bits of the
system that deal with the actual pass mechanics are those that actually
need to deal with the pass mechanics.
Once this separation is made, several simplifications become pretty
obvious in the assumption cache itself. Rather than using a set and
callback value handles, it can just be a vector of weak value handles.
The callers can easily skip the handles that are null, and eventually we
can wrap all of this up behind a filter iterator.
For now, this adds boiler plate to the various passes, but this kind of
boiler plate will end up making it possible to port these passes to the
new pass manager, and so it will end up factored away pretty reasonably.
llvm-svn: 225131
Added instcombine optimizations for BSWAP with AND/OR/XOR ops:
OP( BSWAP(x), BSWAP(y) ) -> BSWAP( OP(x, y) )
OP( BSWAP(x), CONSTANT ) -> BSWAP( OP(x, BSWAP(CONSTANT) ) )
Since its just a one liner, I've also added BSWAP to the DAGCombiner equivalent as well:
fold (OP (bswap x), (bswap y)) -> (bswap (OP x, y))
Refactored bswap-fold tests to use FileCheck instead of just checking that the bswaps had gone.
Differential Revision: http://reviews.llvm.org/D6407
llvm-svn: 223349
Try to convert two compares of a signed range check into a single unsigned compare.
Examples:
(icmp sge x, 0) & (icmp slt x, n) --> icmp ult x, n
(icmp slt x, 0) | (icmp sgt x, n) --> icmp ugt x, n
llvm-svn: 223224
We may be in a situation where the icmps might not be near each other in
a tree of or instructions. Try to dig out related compare instructions
and see if they combine.
N.B. This won't fire on deep trees of compares because rewritting the
tree might end up creating a net increase of IR. We may have to resort
to something more sophisticated if this is a real problem.
llvm-svn: 222928
It is impossible for (x & INT_MAX) == 0 && x == INT_MAX to ever be true.
While this sort of reasoning should normally live in InstSimplify,
the machinery that derives this result is not trivial to split out.
llvm-svn: 222230
This change, which allows @llvm.assume to be used from within computeKnownBits
(and other associated functions in ValueTracking), adds some (optional)
parameters to computeKnownBits and friends. These functions now (optionally)
take a "context" instruction pointer, an AssumptionTracker pointer, and also a
DomTree pointer, and most of the changes are just to pass this new information
when it is easily available from InstSimplify, InstCombine, etc.
As explained below, the significant conceptual change is that known properties
of a value might depend on the control-flow location of the use (because we
care that the @llvm.assume dominates the use because assumptions have
control-flow dependencies). This means that, when we ask if bits are known in a
value, we might get different answers for different uses.
The significant changes are all in ValueTracking. Two main changes: First, as
with the rest of the code, new parameters need to be passed around. To make
this easier, I grouped them into a structure, and I made internal static
versions of the relevant functions that take this structure as a parameter. The
new code does as you might expect, it looks for @llvm.assume calls that make
use of the value we're trying to learn something about (often indirectly),
attempts to pattern match that expression, and uses the result if successful.
By making use of the AssumptionTracker, the process of finding @llvm.assume
calls is not expensive.
Part of the structure being passed around inside ValueTracking is a set of
already-considered @llvm.assume calls. This is to prevent a query using, for
example, the assume(a == b), to recurse on itself. The context and DT params
are used to find applicable assumptions. An assumption needs to dominate the
context instruction, or come after it deterministically. In this latter case we
only handle the specific case where both the assumption and the context
instruction are in the same block, and we need to exclude assumptions from
being used to simplify their own ephemeral values (those which contribute only
to the assumption) because otherwise the assumption would prove its feeding
comparison trivial and would be removed.
This commit adds the plumbing and the logic for a simple masked-bit propagation
(just enough to write a regression test). Future commits add more patterns
(and, correspondingly, more regression tests).
llvm-svn: 217342
The special case did not work when run under -reassociate and can easily
be expressed by a further generalization of an existing pattern.
llvm-svn: 217227
consider: (and (icmp X, Y), (and Z, (icmp A, B)))
It may be possible to combine (icmp X, Y) with (icmp A, B).
If we successfully combine, create an 'and' instruction with Z.
This fixes PR20814.
N.B. There is room for improvement after this change but I'm not
convinced it's worth chasing yet.
llvm-svn: 216814
(X >> Z) & (Y >> Z) -> (X&Y) >> Z for all shifts.
(X >> Z) | (Y >> Z) -> (X|Y) >> Z for all shifts.
(X >> Z) ^ (Y >> Z) -> (X^Y) >> Z for all shifts.
These patterns were previously handled separately in visitAnd()/visitOr()/visitXor().
Differential Revision: http://reviews.llvm.org/D4951
llvm-svn: 216443
Correctness proof of the transform using CVC3-
$ cat t.cvc
A, B : BITVECTOR(32);
QUERY BVXOR(A | B, BVXOR(A,B) ) = A & B;
$ cvc3 t.cvc
Valid.
llvm-svn: 215524
While we can already transform A | (A ^ B) into A | B, things get bad
once we have (A ^ B) | (A ^ B ^ Cst) because reassociation will morph
this into (A ^ B) | ((A ^ Cst) ^ B). Our existing patterns fail once
this happens.
To fix this, we add a new pattern which looks through the tree of xor
binary operators to see that, in fact, there exists a redundant xor
operation.
What follows bellow is a correctness proof of the transform using CVC3.
$ cat t.cvc
A, B, C : BITVECTOR(64);
QUERY BVXOR(A, B) | BVXOR(BVXOR(B, C), A) = BVXOR(A, B) | C;
QUERY BVXOR(BVXOR(A, C), B) | BVXOR(A, B) = BVXOR(A, B) | C;
QUERY BVXOR(A, B) & BVXOR(BVXOR(B, C), A) = BVXOR(A, B) & ~C;
QUERY BVXOR(BVXOR(A, C), B) & BVXOR(A, B) = BVXOR(A, B) & ~C;
$ cvc3 < t.cvc
Valid.
Valid.
Valid.
Valid.
llvm-svn: 214342
"((~A & B) | A) -> (A | B)" and "((A & B) | ~A) -> (~A | B)"
Original Patch credit to Ankit Jain !!
Differential Revision: http://reviews.llvm.org/D4591
llvm-svn: 213676
This patch enables transformations:
BinOp(shuffle(v1), shuffle(v2)) -> shuffle(BinOp(v1, v2))
BinOp(shuffle(v1), const1) -> shuffle(BinOp, const2)
They allow to eliminate extra shuffles in some cases.
Differential Revision: http://reviews.llvm.org/D3525
llvm-svn: 208488
definition below all of the header #include lines, lib/Transforms/...
edition.
This one is tricky for two reasons. We again have a couple of passes
that define something else before the includes as well. I've sunk their
name macros with the DEBUG_TYPE.
Also, InstCombine contains headers that need DEBUG_TYPE, so now those
headers #define and #undef DEBUG_TYPE around their code, leaving them
well formed modular headers. Fixing these headers was a large motivation
for all of these changes, as "leaky" macros of this form are hard on the
modules implementation.
llvm-svn: 206844
header files and into the cpp files.
These files will require more touches as the header files actually use
DEBUG(). Eventually, I'll have to introduce a matched #define and #undef
of DEBUG_TYPE for the header files, but that comes as step N of many to
clean all of this up.
llvm-svn: 206777
a bit surprising, as the class is almost entirely abstracted away from
any particular IR, however it encodes the comparsion predicates which
mutate ranges as ICmp predicate codes. This is reasonable as they're
used for both instructions and constants. Thus, it belongs in the IR
library with instructions and constants.
llvm-svn: 202838
I am really sorry for the noise, but the current state where some parts of the
code use TD (from the old name: TargetData) and other parts use DL makes it
hard to write a patch that changes where those variables come from and how
they are passed along.
llvm-svn: 201827
"(icmp op i8 A, B)" is equivalent to "(icmp op i8 (A & 0xff), B)" as a
degenerate case. Allowing this as a "masked" comparison when analysing "(icmp)
&/| (icmp)" allows us to combine them in more cases.
rdar://problem/7625728
llvm-svn: 189931
Even in cases which aren't universally optimisable like "(A & B) != 0 && (A &
C) != 0", the masks can make one of the comparisons completely redundant. In
this case, since we've gone to the effort of spotting masked comparisons we
should combine them.
rdar://problem/7625728
llvm-svn: 189930
When both constants are positive or both constants are negative,
InstCombine already simplifies comparisons like this, but when
it's exactly zero and -1, the operand sorting ends up reversed
and the pattern fails to match. Handle that special case.
Follow up for rdar://14689217
llvm-svn: 188512
One performs: (X == 13 | X == 14) -> X-13 <u 2
The other: (A == C1 || A == C2) -> (A & ~(C1 ^ C2)) == C1
The problem is that there are certain values of C1 and C2 that
trigger both transforms but the first one blocks out the second,
this generates suboptimal code.
Reordering the transforms should be better in every case and
allows us to do interesting stuff like turn:
%shr = lshr i32 %X, 4
%and = and i32 %shr, 15
%add = add i32 %and, -14
%tobool = icmp ne i32 %add, 0
into:
%and = and i32 %X, 240
%tobool = icmp ne i32 %and, 224
llvm-svn: 179493
(or (bool?A:B),(bool?C:D)) --> (bool?(or A,C):(or B,D))
By the time the OR is visited, both the SELECTs have been visited and not
optimized and the OR itself hasn't been transformed so we do this transform in
the hopes that the new ORs will be optimized.
The transform is explicitly disabled for vector-selects until "codegen matures
to handle them better".
Patch by Muhammad Tauqir!
llvm-svn: 175380
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.
There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.
The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.
I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).
I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.
llvm-svn: 171366
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.
Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]
llvm-svn: 169131
Enhancement to InstCombine. Try to catch this opportunity:
---------------------------------------------------------------
((X^C1) >> C2) ^ C3 => (X>>C2) ^ ((C1>>C2)^C3)
where the subexpression "X ^ C1" has more than one uses, and
"(X^C1) >> C2" has single use.
----------------------------------------------------------------
Reviewed by Nadav (with minor change per his request).
llvm-svn: 168615
an assert on Darwin llvm-gcc builds.
Assertion failed: (castIsValid(op, S, Ty) && "Invalid cast!"), function Create, file /Users/buildslave/zorg/buildbot/smooshlab/slave-0.8/build.llvm-gcc-i386-darwin9-RA/llvm.src/lib/VMCore/Instructions.cpp, li\
ne 2067.
etc.
http://smooshlab.apple.com:8013/builders/llvm-gcc-i386-darwin9-RA/builds/2354
--- Reverse-merging r134893 into '.':
U include/llvm/Target/TargetData.h
U include/llvm/DerivedTypes.h
U tools/bugpoint/ExtractFunction.cpp
U unittests/Support/TypeBuilderTest.cpp
U lib/Target/ARM/ARMGlobalMerge.cpp
U lib/Target/TargetData.cpp
U lib/VMCore/Constants.cpp
U lib/VMCore/Type.cpp
U lib/VMCore/Core.cpp
U lib/Transforms/Utils/CodeExtractor.cpp
U lib/Transforms/Instrumentation/ProfilingUtils.cpp
U lib/Transforms/IPO/DeadArgumentElimination.cpp
U lib/CodeGen/SjLjEHPrepare.cpp
--- Reverse-merging r134888 into '.':
G include/llvm/DerivedTypes.h
U include/llvm/Support/TypeBuilder.h
U include/llvm/Intrinsics.h
U unittests/Analysis/ScalarEvolutionTest.cpp
U unittests/ExecutionEngine/JIT/JITTest.cpp
U unittests/ExecutionEngine/JIT/JITMemoryManagerTest.cpp
U unittests/VMCore/PassManagerTest.cpp
G unittests/Support/TypeBuilderTest.cpp
U lib/Target/MBlaze/MBlazeIntrinsicInfo.cpp
U lib/Target/Blackfin/BlackfinIntrinsicInfo.cpp
U lib/VMCore/IRBuilder.cpp
G lib/VMCore/Type.cpp
U lib/VMCore/Function.cpp
G lib/VMCore/Core.cpp
U lib/VMCore/Module.cpp
U lib/AsmParser/LLParser.cpp
U lib/Transforms/Utils/CloneFunction.cpp
G lib/Transforms/Utils/CodeExtractor.cpp
U lib/Transforms/Utils/InlineFunction.cpp
U lib/Transforms/Instrumentation/GCOVProfiling.cpp
U lib/Transforms/Scalar/ObjCARC.cpp
U lib/Transforms/Scalar/SimplifyLibCalls.cpp
U lib/Transforms/Scalar/MemCpyOptimizer.cpp
G lib/Transforms/IPO/DeadArgumentElimination.cpp
U lib/Transforms/IPO/ArgumentPromotion.cpp
U lib/Transforms/InstCombine/InstCombineCompares.cpp
U lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
U lib/Transforms/InstCombine/InstCombineCalls.cpp
U lib/CodeGen/DwarfEHPrepare.cpp
U lib/CodeGen/IntrinsicLowering.cpp
U lib/Bitcode/Reader/BitcodeReader.cpp
llvm-svn: 134949
This shouldn't happen in practice because the icmp would be a constant.
Add a check so we don't miscompile code if something goes wrong.
llvm-svn: 130446
intersection of the LHS and RHS ConstantRanges and return "false" when
the range is empty.
This simplifies some code and catches some extra cases.
llvm-svn: 126744
We usually catch this kind of optimization through InstSimplify's distributive
magic, but or doesn't distribute over xor in general.
"A | ~(A | B) -> A | ~B" hits 24 times on gcc.c.
llvm-svn: 126081
versions of creation functions. Eventually, the "insertion point" versions
of these should just be removed, we do have IRBuilder afterall.
Do a massive rewrite of much of pattern match. It is now shorter and less
redundant and has several other widgets I will be using in other patches.
Among other changes, m_Div is renamed to m_IDiv (since it only matches
integer divides) and m_Shift is gone (it used to match all binops!!) and
we now have m_LogicalShift for the one client to use.
Enhance IRBuilder to have "isExact" arguments to things like CreateUDiv
and reduce redundancy within IRbuilder by having these methods chain to
each other more instead of duplicating code.
llvm-svn: 125194
if both A op B and A op C simplify. This fires fairly often but doesn't
make that much difference. On gcc-as-one-file it removes two "and"s and
turns one branch into a select.
llvm-svn: 122399
fairly systematic way in instcombine. Some of these cases were already dealt
with, in which case I removed the existing code. The case of Add has a bunch of
funky logic which covers some of this plus a few variants (considers shifts to be
a form of multiplication), which I didn't touch. The simplification performed is:
A*B+A*C -> A*(B+C). The improvement is to do this in cases that were not already
handled [such as A*B-A*C -> A*(B-C), which was reported on the mailing list], and
also to do it more often by not checking for "only one use" if "B+C" simplifies.
llvm-svn: 120024
instructions out of InstCombine and into InstructionSimplify. While
there, introduce an m_AllOnes pattern to simplify matching with integers
and vectors with all bits equal to one.
llvm-svn: 119536
SimplifyAssociativeOrCommutative) "(A op C1) op C2" -> "A op (C1 op C2)",
which previously was only done if C1 and C2 were constants, to occur whenever
"C1 op C2" simplifies (a la InstructionSimplify). Since the simplifying operand
combination can no longer be assumed to be the right-hand terms, consider all of
the possible permutations. When compiling "gcc as one big file", transform 2
(i.e. using right-hand operands) fires about 4000 times but it has to be said
that most of the time the simplifying operands are both constants. Transforms
3, 4 and 5 each fired once. Transform 6, which is an existing transform that
I didn't change, never fired. With this change, the testcase is now optimized
perfectly with one run of instcombine (previously it required instcombine +
reassociate + instcombine, and it may just have been luck that this worked).
llvm-svn: 119002
to expose greater opportunities for store narrowing in codegen. This patch fixes a potential
infinite loop in instcombine caused by one of the introduced transforms being overly aggressive.
llvm-svn: 113763
This can result in increased opportunities for store narrowing in code generation. Update a number of
tests for this change. This fixes <rdar://problem/8285027>.
Additionally, because this inverts the order of ors and ands, some patterns for optimizing or-of-and-of-or
no longer fire in instances where they did originally. Add a simple transform which recaptures most of these
opportunities: if we have an or-of-constant-or and have failed to fold away the inner or, commute the order
of the two ors, to give the non-constant or a chance for simplification instead.
llvm-svn: 113679
the corresponding or-icmp-and pattern. This has the added benefit of doing
the matching earlier, and thus being less susceptible to being confused by
earlier transforms.
llvm-svn: 108429
parts of the cmp|cmp and cmp&cmp folding logic wasn't prepared for vectors
(unrelated to the bug but noticed while in the code) and the code was
*definitely* not safe to use by the (cast icmp)|(cast icmp) handling logic
that I added in r95855. Fix all this up by changing the various routines
to more consistently use IRBuilder and not pass in the I which had the wrong
type.
llvm-svn: 97801
long test(long x) { return (x & 123124) | 3; }
Currently compiles to:
_test:
orl $3, %edi
movq %rdi, %rax
andq $123127, %rax
ret
This is because instruction and DAG combiners canonicalize
(or (and x, C), D) -> (and (or, D), (C | D))
However, this is only profitable if (C & D) != 0. It gets in the way of the
3-addressification because the input bits are known to be zero.
llvm-svn: 97616
what it does. Enhance it to return false to optimizing vector
sign extensions from vector comparisions, which is the idiom used
to get a splatted vector for a vector comparison.
Doing this breaks vector-casts.ll, add some compensating
transformations to handle the important case they cover without
depending on this canonicalization.
This fixes rdar://7434900 a serious pessimization of vector compares.
llvm-svn: 95855
xform it is checking to actually pass. There is no need to match
m_SelectCst<0, -1> since instcombine canonicalizes that into not(sext).
Add matches for sext(not(x)) in addition to not(sext(x)).
llvm-svn: 95420
"sext cond" instead of a select. This simplifies some instcombine
code, matches the policy for zext (cond ? 1 : 0 -> zext), and allows
us to generate better code for a testcase on ppc.
llvm-svn: 94339
Sanjay Patel