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authorJames Molloy <james.molloy@arm.com>2015-05-17 08:27:27 +0000
committerJames Molloy <james.molloy@arm.com>2015-05-17 08:27:27 +0000
commit53958e187a624142498f42d4a67a8e64b65b1c6c (patch)
treea637b90f0766abb83148286e028b5d4f8aa4df55 /llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
parent0928553eecaa835b9983c8afbc8ee3948327a06c (diff)
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Reapply r237520 with another fix for infinite looping
SimplifyDemandedBits was "simplifying" a constant by removing just sign bits. This caused a canonicalization race between different parts of instcombine. Fix and regression test added - third time lucky? llvm-svn: 237539
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp')
-rw-r--r--llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp24
1 files changed, 18 insertions, 6 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index b13d3ed..d2fbcdd 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1154,18 +1154,30 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
}
// See if we can fold the select into one of our operands.
- if (SI.getType()->isIntegerTy()) {
+ if (SI.getType()->isIntOrIntVectorTy()) {
if (Instruction *FoldI = FoldSelectIntoOp(SI, TrueVal, FalseVal))
return FoldI;
Value *LHS, *RHS, *LHS2, *RHS2;
- SelectPatternFlavor SPF = matchSelectPattern(&SI, LHS, RHS);
+ Instruction::CastOps CastOp;
+ SelectPatternFlavor SPF = matchSelectPattern(&SI, LHS, RHS, &CastOp);
- // MAX(MAX(a, b), a) -> MAX(a, b)
- // MIN(MIN(a, b), a) -> MIN(a, b)
- // MAX(MIN(a, b), a) -> a
- // MIN(MAX(a, b), a) -> a
if (SPF) {
+ // Canonicalize so that type casts are outside select patterns.
+ if (LHS->getType()->getPrimitiveSizeInBits() !=
+ SI.getType()->getPrimitiveSizeInBits()) {
+ CmpInst::Predicate Pred = getICmpPredicateForMinMax(SPF);
+ Value *Cmp = Builder->CreateICmp(Pred, LHS, RHS);
+ Value *NewSI = Builder->CreateCast(CastOp,
+ Builder->CreateSelect(Cmp, LHS, RHS),
+ SI.getType());
+ return ReplaceInstUsesWith(SI, NewSI);
+ }
+
+ // MAX(MAX(a, b), a) -> MAX(a, b)
+ // MIN(MIN(a, b), a) -> MIN(a, b)
+ // MAX(MIN(a, b), a) -> a
+ // MIN(MAX(a, b), a) -> a
if (SelectPatternFlavor SPF2 = matchSelectPattern(LHS, LHS2, RHS2))
if (Instruction *R = FoldSPFofSPF(cast<Instruction>(LHS),SPF2,LHS2,RHS2,
SI, SPF, RHS))