From ed988fb97d8cbede0880c1f254ff8788803dccb3 Mon Sep 17 00:00:00 2001 From: Arnold Schwaighofer Date: Thu, 26 Jun 2014 19:51:19 +0000 Subject: [PATCH] GVN: Preserve invariant.load metadata If both instructions to be replaced are marked invariant the resulting instruction is invariant. rdar://13358910 Fix by Erik Eckstein! llvm-svn: 211801 --- llvm/lib/Transforms/Scalar/GVN.cpp | 4 ++++ llvm/test/Transforms/GVN/invariant-load.ll | 30 ++++++++++++++++++++++++++++++ 2 files changed, 34 insertions(+) create mode 100644 llvm/test/Transforms/GVN/invariant-load.ll diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp index 56781d4..106eba0 100644 --- a/llvm/lib/Transforms/Scalar/GVN.cpp +++ b/llvm/lib/Transforms/Scalar/GVN.cpp @@ -1798,6 +1798,10 @@ static void patchReplacementInstruction(Instruction *I, Value *Repl) { case LLVMContext::MD_fpmath: ReplInst->setMetadata(Kind, MDNode::getMostGenericFPMath(IMD, ReplMD)); break; + case LLVMContext::MD_invariant_load: + // Only set the !invariant.load if it is present in both instructions. + ReplInst->setMetadata(Kind, IMD); + break; } } } diff --git a/llvm/test/Transforms/GVN/invariant-load.ll b/llvm/test/Transforms/GVN/invariant-load.ll new file mode 100644 index 0000000..73a1278 --- /dev/null +++ b/llvm/test/Transforms/GVN/invariant-load.ll @@ -0,0 +1,30 @@ +; RUN: opt -basicaa -gvn -S < %s | FileCheck %s + +define i32 @test1(i32* nocapture %p, i8* nocapture %q) { +; CHECK-LABEL: test1 +; CHECK: %x = load i32* %p, align 4, !invariant.load !0 +; CHECK-NOT: %y = load +entry: + %x = load i32* %p, align 4, !invariant.load !0 + %conv = trunc i32 %x to i8 + store i8 %conv, i8* %q, align 1 + %y = load i32* %p, align 4, !invariant.load !0 + %add = add i32 %y, 1 + ret i32 %add +} + +define i32 @test2(i32* nocapture %p, i8* nocapture %q) { +; CHECK-LABEL: test2 +; CHECK-NOT: !invariant.load +; CHECK-NOT: %y = load +entry: + %x = load i32* %p, align 4 + %conv = trunc i32 %x to i8 + store i8 %conv, i8* %q, align 1 + %y = load i32* %p, align 4, !invariant.load !0 + %add = add i32 %y, 1 + ret i32 %add +} + +!0 = metadata !{ } + -- 2.7.4