diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp index 03a9aa8189a..9a81ec51dda 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -2848,7 +2848,17 @@ void SelectionDAGBuilder::visitLoad(const LoadInst &I) { bool isVolatile = I.isVolatile(); bool isNonTemporal = I.getMetadata(LLVMContext::MD_nontemporal) != nullptr; - bool isInvariant = I.getMetadata(LLVMContext::MD_invariant_load) != nullptr; + + // The IR notion of invariant_load only guarantees that all *non-faulting* + // invariant loads result in the same value. The MI notion of invariant load + // guarantees that the load can be legally moved to any location within its + // containing function. The MI notion of invariant_load is stronger than the + // IR notion of invariant_load -- an MI invariant_load is an IR invariant_load + // with a guarantee that the location being loaded from is dereferenceable + // throughout the function's lifetime. + + bool isInvariant = I.getMetadata(LLVMContext::MD_invariant_load) != nullptr && + isDereferenceablePointer(SV, *DAG.getTarget().getDataLayout()); unsigned Alignment = I.getAlignment(); AAMDNodes AAInfo; diff --git a/test/CodeGen/X86/pr23603.ll b/test/CodeGen/X86/pr23603.ll new file mode 100644 index 00000000000..6f856aedb8d --- /dev/null +++ b/test/CodeGen/X86/pr23603.ll @@ -0,0 +1,24 @@ +; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s + +declare void @free_v() + +define void @f(i32* %x, i32 %c32, i32* %y) { +; CHECK-LABEL: f + entry: + %v = load i32, i32* %x, !invariant.load !0 +; CHECK: movl (%rdi), %ebx +; CHECK: free_v +; CHECK-NOT: movl (%rdi), %ebx + call void @free_v() + %c = icmp ne i32 %c32, 0 + br i1 %c, label %left, label %merge + + left: + store i32 %v, i32* %y + br label %merge + + merge: + ret void +} + +!0 = !{}