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| author | Noah Goldstein <goldstein.w.n@gmail.com> | 2024-06-23 00:16:58 +0800 |
|---|---|---|
| committer | Noah Goldstein <goldstein.w.n@gmail.com> | 2024-06-23 11:15:47 +0800 |
| commit | b37a4b9991a0a669594b53caa0eb75f489211d69 (patch) | |
| tree | 4ff77fd7f939a15411116e4f02ad6a0b511346cb | |
| parent | 61c4d7b9231d22f8cff7a6a6b3b52d401cba9f6f (diff) | |
| download | llvm-b37a4b9991a0a669594b53caa0eb75f489211d69.zip llvm-b37a4b9991a0a669594b53caa0eb75f489211d69.tar.gz llvm-b37a4b9991a0a669594b53caa0eb75f489211d69.tar.bz2 | |
[InstCombine] Improve coverage of `foldSelectValueEquivalence` for non-constants
If f(Y) simplifies to Y, replace with Y. This requires Y to be
non-undef.
Closes #94719
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp | 2 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/select-cmp-eq-op-fold.ll | 6 |
2 files changed, 3 insertions, 5 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp index fbac209..27563d4 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp @@ -1310,7 +1310,7 @@ Instruction *InstCombinerImpl::foldSelectValueEquivalence(SelectInst &Sel, // If NewOp is a constant and OldOp is not replace iff NewOp doesn't // contain and undef elements. - if (match(NewOp, m_ImmConstant())) { + if (match(NewOp, m_ImmConstant()) || NewOp == V) { if (isGuaranteedNotToBeUndef(NewOp, SQ.AC, &Sel, &DT)) return replaceOperand(Sel, Swapped ? 2 : 1, V); return nullptr; diff --git a/llvm/test/Transforms/InstCombine/select-cmp-eq-op-fold.ll b/llvm/test/Transforms/InstCombine/select-cmp-eq-op-fold.ll index ec82b19..2f2c2d3 100644 --- a/llvm/test/Transforms/InstCombine/select-cmp-eq-op-fold.ll +++ b/llvm/test/Transforms/InstCombine/select-cmp-eq-op-fold.ll @@ -6,8 +6,7 @@ declare void @use.i8(i8) define i8 @replace_with_y_noundef(i8 %x, i8 noundef %y, i8 %z) { ; CHECK-LABEL: @replace_with_y_noundef( ; CHECK-NEXT: [[CMP:%.*]] = icmp eq i8 [[X:%.*]], [[Y:%.*]] -; CHECK-NEXT: [[AND:%.*]] = and i8 [[X]], [[Y]] -; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i8 [[AND]], i8 [[Z:%.*]] +; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i8 [[Y]], i8 [[Z:%.*]] ; CHECK-NEXT: ret i8 [[SEL]] ; %cmp = icmp eq i8 %x, %y @@ -20,8 +19,7 @@ define i8 @replace_with_x_noundef(i8 noundef %x, i8 %y, i8 %z) { ; CHECK-LABEL: @replace_with_x_noundef( ; CHECK-NEXT: [[CMP:%.*]] = icmp ne i8 [[X:%.*]], [[Y:%.*]] ; CHECK-NEXT: call void @use.i1(i1 [[CMP]]) -; CHECK-NEXT: [[AND:%.*]] = or i8 [[X]], [[Y]] -; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i8 [[Z:%.*]], i8 [[AND]] +; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i8 [[Z:%.*]], i8 [[X]] ; CHECK-NEXT: ret i8 [[SEL]] ; %cmp = icmp ne i8 %x, %y |