diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 4 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/memmove.ll | 6 |
2 files changed, 10 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 20204154d0..8c2dc3e92f 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -9131,6 +9131,10 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) { CI.setOperand(0, Intrinsic::getDeclaration(M, MemCpyID)); Changed = true; } + + // memmove(x,x,size) -> noop. + if (MMI->getSource() == MMI->getDest()) + return EraseInstFromFunction(CI); } // If we can determine a pointer alignment that is bigger than currently diff --git a/test/Transforms/InstCombine/memmove.ll b/test/Transforms/InstCombine/memmove.ll index 2cb346f112..09ec67d265 100644 --- a/test/Transforms/InstCombine/memmove.ll +++ b/test/Transforms/InstCombine/memmove.ll @@ -34,3 +34,9 @@ define i32 @test3() { ret i32 0 } +; PR2370 +define void @test4(i8* %a) { + tail call void @llvm.memmove.i32( i8* %a, i8* %a, i32 100, i32 1 ) + ret void +} + |