diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp index 6c392145a50..dc8fb39f173 100644 --- a/lib/VMCore/ConstantFold.cpp +++ b/lib/VMCore/ConstantFold.cpp @@ -773,6 +773,13 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, } } } + + // 0 / x -> 0. + if ((Opcode == Instruction::UDiv || + Opcode == Instruction::SDiv) && + CI1->isZero()) + return const_cast(C1); + } else if (const ConstantFP *CFP1 = dyn_cast(C1)) { if (const ConstantFP *CFP2 = dyn_cast(C2)) { APFloat C1V = CFP1->getValueAPF(); diff --git a/test/Transforms/ConstProp/div-zero.ll b/test/Transforms/ConstProp/div-zero.ll new file mode 100644 index 00000000000..166c643dcc9 --- /dev/null +++ b/test/Transforms/ConstProp/div-zero.ll @@ -0,0 +1,12 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {ret i32 0} +; PR4424 +declare void @ext() + +define i32 @foo(i32 %ptr) { +entry: + %zero = sub i32 %ptr, %ptr ; [#uses=1] + %div_zero = sdiv i32 %zero, ptrtoint (i32* getelementptr (i32* null, +i32 1) to i32) ; [#uses=1] + ret i32 %div_zero +} +