diff options
| -rw-r--r-- | lib/Transforms/InstCombine/InstCombineCompares.cpp | 14 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/icmp.ll | 26 |
2 files changed, 40 insertions, 0 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp index bb7763ddeb..5a91c7b970 100644 --- a/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -607,6 +607,20 @@ Instruction *InstCombiner::FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS, return new ICmpInst(ICmpInst::getSignedPredicate(Cond), GEPLHS->getOperand(0), GEPRHS->getOperand(0)); + // If we're comparing GEPs with two base pointers that only differ in type + // and both GEPs have only constant indices or just one use, then fold + // the compare with the adjusted indices. + if (TD && + (GEPLHS->hasAllConstantIndices() || GEPLHS->hasOneUse()) && + (GEPRHS->hasAllConstantIndices() || GEPRHS->hasOneUse()) && + PtrBase->stripPointerCasts() == + GEPRHS->getOperand(0)->stripPointerCasts()) { + Value *Cmp = Builder->CreateICmp(ICmpInst::getSignedPredicate(Cond), + EmitGEPOffset(GEPLHS), + EmitGEPOffset(GEPRHS)); + return ReplaceInstUsesWith(I, Cmp); + } + // Otherwise, the base pointers are different and the indices are // different, bail out. return 0; diff --git a/test/Transforms/InstCombine/icmp.ll b/test/Transforms/InstCombine/icmp.ll index 1652e71401..09152f0986 100644 --- a/test/Transforms/InstCombine/icmp.ll +++ b/test/Transforms/InstCombine/icmp.ll @@ -589,3 +589,29 @@ define void @test58() nounwind { ret void } declare i32 @test58_d(i64) + +define i1 @test59(i8* %foo) { + %bit = bitcast i8* %foo to i32* + %gep1 = getelementptr inbounds i32* %bit, i64 2 + %gep2 = getelementptr inbounds i8* %foo, i64 10 + %cast1 = bitcast i32* %gep1 to i8* + %cmp = icmp ult i8* %cast1, %gep2 + %use = ptrtoint i8* %cast1 to i64 + %call = call i32 @test58_d(i64 %use) nounwind + ret i1 %cmp +; CHECK: @test59 +; CHECK: ret i1 true +} + +define i1 @test60(i8* %foo, i64 %i, i64 %j) { + %bit = bitcast i8* %foo to i32* + %gep1 = getelementptr inbounds i32* %bit, i64 %i + %gep2 = getelementptr inbounds i8* %foo, i64 %j + %cast1 = bitcast i32* %gep1 to i8* + %cmp = icmp ult i8* %cast1, %gep2 + ret i1 %cmp +; CHECK: @test60 +; CHECK-NEXT: %gep1.idx = shl nuw i64 %i, 2 +; CHECK-NEXT: icmp slt i64 %gep1.idx, %j +; CHECK-NEXT: ret i1 +} |