Index: lib/Analysis/GlobalsModRef.cpp =================================================================== --- lib/Analysis/GlobalsModRef.cpp +++ lib/Analysis/GlobalsModRef.cpp @@ -480,8 +480,8 @@ const std::vector &SCC = *I; assert(!SCC.empty() && "SCC with no functions?"); - if (!SCC[0]->getFunction()) { - // Calls externally - can't say anything useful. Remove any existing + if (!SCC[0]->getFunction() || SCC[0]->getFunction()->mayBeOverridden()) { + // Calls externally or is weak - can't say anything useful. Remove any existing // function records (may have been created when scanning globals). for (auto *Node : SCC) FunctionInfos.erase(Node->getFunction()); Index: test/Analysis/GlobalsModRef/weak-interposition.ll =================================================================== --- /dev/null +++ test/Analysis/GlobalsModRef/weak-interposition.ll @@ -0,0 +1,24 @@ +; RUN: opt -S -O1 -enable-non-lto-gmr=true < %s | FileCheck %s + +@a = common global i32 0, align 4 + +; @hook_me is weak, so GMR must not eliminate the reload of @a in @f, +; even though @hook_me doesn't mod or ref @a. + +; Function Attrs: nounwind ssp uwtable +define weak i32 @hook_me() { + ret i32 0 +} + +; Function Attrs: nounwind ssp uwtable +define i32 @f() { + %1 = alloca i32, align 4 + store i32 4, i32* @a, align 4 + %2 = call i32 @hook_me() + ; CHECK: load i32, i32* @a, align 4 + %3 = load i32, i32* @a, align 4 + %4 = add nsw i32 %3, %2 + store i32 %4, i32* @a, align 4 + %5 = load i32, i32* %1 + ret i32 %5 +}