We previously included debug instructions when counting instructions when
looking for loads to combine. This meant that the presence of debug
instructions could affect optimization, as shown in the updated testcase.
This fixes#69925.
The comments contain IR where some instructions don't fit in
80 columns. The extra part of the line was placed in front of
the next IR instruction instead of on its own line.
This reverts commit 5dde755188e34c0ba5304365612904476c8adfda,
cbfcf90152de5392a36d0a0241eef25f5e159eef and
8981520b19f2d2fe3d2bc80cf26318ee6b5b7473 due to a miscompile introduced in
8981520b19f2d2fe3d2bc80cf26318ee6b5b7473 (see
https://reviews.llvm.org/D154725#4568845 for details)
Differential Revision: https://reviews.llvm.org/D157430
As pointed out in D125755 the operand of a call to getCastInstrCost had the Src
and Dst the wrong way around.
Differential Revision: https://reviews.llvm.org/D154841
Partial progress towards replacing in-tree uses of
`Type::getPointerTo()`.
If `getPointerTo()` is used solely to support an unnecessary bitcast,
remove the bitcast.
Reviewed By: barannikov88, nikic
Differential Revision: https://reviews.llvm.org/D153307
This seems to be an issue currently where there are nested/chained GEP/BitCast Pointers.
The patch generates a new GEP for the wider load to avoid dominance problems.
Differential Revision: https://reviews.llvm.org/D150864
This patch involves boolean ring to simplify logical operations. We can treat `&` as ring multiplication and `^` as ring addition.
So we need to canonicalize all other operations to `*` `+`. Like:
```
a & b -> a * b
a ^ b -> a + b
~a -> a + 1
a | b -> a * b + a + b
c ? a : b -> c * a + (c + 1) * b
```
In the code, we use a mask set to represent an expression. Every value that is not comes from logical operations could be a bit in the mask.
The mask itself is a multiplication chain. The mask set is an addiction chain.
We can calculate two expressions based on boolean algebras.
For now, the initial patch only enabled on and/or/xor, Later we can enhance the code step by step.
Reference: https://en.wikipedia.org/wiki/Boolean_ring
Reviewed By: spatel
Differential Revision: https://reviews.llvm.org/D142803
Much of foldLoadsRecursive relies on knowing the size of loaded
data, which is not possible for scalable vector types. However,
the logic of combining two small loads into one bigger load does
not apply for vector types so rather than converting the algorithm
to use TypeSize I've simply added an early exit for vectors.
Fixes#59510
Differential Revision: https://reviews.llvm.org/D140106
This patch updates the load insert point of the merged load in AggressiveInstCombine().
This is done to handle the reported test breaks by handling Alias Analysis correctly.
Differential Revision: https://reviews.llvm.org/D137201
A target can return if a misaligned access is 'fast' as defined
by the target or not. In reality there can be different levels
of 'fast' and 'slow'. This patch changes the boolean 'Fast'
argument of the allowsMisalignedMemoryAccesses family of functions
to an unsigned representing its speed.
A target can still define it as it wants and the direct translation
of the current code uses 0 and 1 for current false and true. This
makes the change an NFC.
Subsequent patch will start using an actual value of speed in
the load/store vectorizer to compare if a vectorized access going
to be not just fast, but not slower than before.
Differential Revision: https://reviews.llvm.org/D124217
As part of legacy PM optimization pipeline removal.
This shouldn't be used in codegen pipelines so it should be ok to remove.
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D137116
This patch is to address the test cases in which the load has to be inserted at a right point. This happens when there is a store b/w the loads.
This patch reverts the loads merge in all cases when stores are present b/w loads and will eventually be replaced with proper fix and test cases.
Differential Revision: https://reviews.llvm.org/D137333
This patch extends the load merge/widen in AggressiveInstCombine() to handle reverse load patterns.
Differential Revision: https://reviews.llvm.org/D135137
In the case of non-opaque pointers, when combining consecutive loads,
need to bitcast the pointer source to the combined type size, otherwise
asserts are triggered.
Differential Revision: https://reviews.llvm.org/D135249
The patch simplifies some of the patterns as below
1. (ZExt(L1) << shift1) | (ZExt(L2) << shift2) -> ZExt(L3) << shift1
2. (ZExt(L1) << shift1) | ZExt(L2) -> ZExt(L3)
The pattern is indicative of the fact that the loads are being merged to a wider load and the only use of this pattern is with a wider load. In this case for a non-atomic/non-volatile loads reduce the pattern to a combined load which would improve the cost of inlining, unrolling, vectorization etc.
Fix the error reported on reverse load merge.
Differential Revision: https://reviews.llvm.org/D127392
The patch simplifies some of the patterns as below
1. (ZExt(L1) << shift1) | (ZExt(L2) << shift2) -> ZExt(L3) << shift1
2. (ZExt(L1) << shift1) | ZExt(L2) -> ZExt(L3)
The pattern is indicative of the fact that the loads are being merged to a wider load and the only use of this pattern is with a wider load. In this case for a non-atomic/non-volatile loads reduce the pattern to a combined load which would improve the cost of inlining, unrolling, vectorization etc.
Differential Revision: https://reviews.llvm.org/D127392
The bug reported on the [0] has been fixed.
The issue was we have not checked if the global variables that
represent cttz tables was constant.
There is a new negative test added in negative-lower-table-based-cttz.ll
that represents this.
[0] https://reviews.llvm.org/rGdf868edee561eb973edd85ec9df41c67aa0bff6b
This reverts commit 053841c5624ca7eacd108a26071d8a1cefe1bebd.
We faced a use-after-free after pushing the D113291, since the
foldSqrt() has a call to eraseFromParent(). The function
should be at the end of the main loop that folds the patterns.
This patch fixes that.
This is an alternate to D129155 that uses TTI.haveFastSqrt() to avoid a
potential miscompile for programs with reads of errno. Moving the transform
to AggressiveInstCombine provides access to TTI.
If a sqrt call has "nnan", that implies that the input argument is never
negative because sqrt of {negative number} --> NAN.
If the argument is never negative and the call can be lowered without a
libcall, then we can assume that errno accesses are unchanged after lowering,
so the call can be translated to the LLVM intrinsic (which is expected to
become inline code).
This affects codegen for targets like x86 that have sqrt instructions, but
still have to conservatively assume that a libcall may be needed to set
errno as shown in issue #52620 and issue #56383.
This patch won't solve those examples - we will need to extend this to use
CannotBeOrderedLessThanZero or similar, enhance that analysis for new
operators, and/or deal with llvm.assume too.
Differential Revision: https://reviews.llvm.org/D129167
This adds a fold for aggressive instcombine that converts
smin(smax(fptosi(x))) into a llvm.fptosi.sat, providing that the
saturation constants are correct and the cost of the llvm.fptosi.sat is
lower.
Unfortunately, a llvm.fptosi.sat cannot always be converted back to a
smin/smax/fptosi. The llvm.fptosi.sat intrinsic is more defined that the
original, which produces poison if the original fptosi was out of range.
The llvm.fptosi.sat will saturate any value, so needs to be expanded to
a fptosi(fpmin(fpmax(x))), which can be worse for codegeneration
depending on the target.
So this change thais conditional on the backend reporting that the
llvm.fptosi.sat is cheaper that the original smin+smax+fptost. This is
a change to the way that AggressiveInstrcombine has worked in the past.
Instead of just being a canonicalization pass, that canonicalization can
be dependant on the target in certain specific cases.
Differential Revision: https://reviews.llvm.org/D125755
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
Currently all AA analyses marked as preserved are stateless, not taking
into account their dependent analyses. So there's no need to mark them
as preserved, they won't be invalidated unless their analyses are.
SCEVAAResults was the one exception to this, it was treated like a
typical analysis result. Make it like the others and don't invalidate
unless SCEV is invalidated.
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D102032
The fold currently only handles rotation patterns, but with the maturation of backend funnel shift handling we can now realistically handle all funnel shift patterns.
This should allow us to begin resolving PR46896 et al.
Ensure we block poison in a funnel shift value - similar to rG0fe91ad463fea9d08cbcd640a62aa9ca2d8d05e0
Reapplied with fix for PR48068 - we weren't checking that the shift values could be hoisted from their basicblocks.
Differential Revision: https://reviews.llvm.org/D90625
This reverts commit 59b22e495c15d2830f41381a327f5d6bf49ff416.
That commit broke building for ARM and AArch64, reproducible like this:
$ cat apedec-reduced.c
a;
b(e) {
int c;
unsigned d = f();
c = d >> 32 - e;
return c;
}
g() {
int h = i();
if (a)
h = h << a | b(a);
return h;
}
$ clang -target aarch64-linux-gnu -w -c -O3 apedec-reduced.c
clang: ../lib/Transforms/InstCombine/InstructionCombining.cpp:3656: bool llvm::InstCombinerImpl::run(): Assertion `DT.dominates(BB, UserParent) && "Dominance relation broken?"' failed.
Same thing for e.g. an armv7-linux-gnueabihf target.
The fold currently only handles rotation patterns, but with the maturation of backend funnel shift handling we can now realistically handle all funnel shift patterns.
This should allow us to begin resolving PR46896 et al.
Differential Revision: https://reviews.llvm.org/D90625
Replace m_ConstantInt with m_APInt to support uniform vectors (with no undef elements)
Adding non-undef support would involve some refactoring of the MaskOps struct but this might still be worth it.
