Index: lib/Analysis/GlobalsModRef.cpp =================================================================== --- lib/Analysis/GlobalsModRef.cpp +++ lib/Analysis/GlobalsModRef.cpp @@ -863,7 +863,11 @@ GetUnderlyingObjects(A, Objects, DL); // All objects must be identified. - if (!std::all_of(Objects.begin(), Objects.end(), isIdentifiedObject)) + if (!std::all_of(Objects.begin(), Objects.end(), isIdentifiedObject) && + // Try ::alias to see if all objects are known not to alias GV. + !std::all_of(Objects.begin(), Objects.end(), [&](Value *V) { + return this->alias(MemoryLocation(V), MemoryLocation(GV)) == NoAlias; + })) return ConservativeResult; if (std::find(Objects.begin(), Objects.end(), GV) != Objects.end()) Index: test/Analysis/GlobalsModRef/no-escape.ll =================================================================== --- /dev/null +++ test/Analysis/GlobalsModRef/no-escape.ll @@ -0,0 +1,65 @@ +; RUN: opt < %s -basicaa -globals-aa -S -enable-non-lto-gmr=true -licm | FileCheck %s + +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-apple-macosx10.10.0" + +@b = common global i32 0, align 4 +@c = internal global i32 0, align 4 +@d = common global i32 0, align 4 +@e = common global i32* null, align 4 + +define void @foo(i32* %P) noinline { +; CHECK: define void @foo + %loadp = load i32, i32* %P, align 4 + store i32 %loadp, i32* @d, align 4 + ret void +} + +define void @bar() noinline { +; CHECK: define void @bar + %loadp = load i32, i32* @d, align 4 + store i32 %loadp, i32* @c, align 4 + ret void +} + +define i32 @main() { +entry: + %retval = alloca i32, align 4 + %c = alloca [1 x i32], align 4 + store i32 0, i32* %retval, align 4 + call void @bar() + store i32 0, i32* @b, align 4 + br label %for.cond + ;; Check that @c is LICM'ed out. +; CHECK: load i32, i32* @c +for.cond: ; preds = %for.inc, %entry +; CHECK-LABEL: for.cond: +; CHECK: load i32, i32* @b + %a1 = load i32, i32* @b, align 4 + %aa2 = load i32, i32* @c, align 4 + %add = add nsw i32 %a1, %aa2 + %p1 = load i32*, i32** @e, align 4 + call void @foo(i32* %p1) + %cmp = icmp slt i32 %add, 3 + br i1 %cmp, label %for.body, label %for.end + +for.body: ; preds = %for.cond + %a2 = load i32, i32* @b, align 4 + %idxprom = sext i32 %a2 to i64 + br label %for.inc + +for.inc: ; preds = %for.body + %a3 = load i32, i32* @b, align 4 + %inc = add nsw i32 %a3, 1 + store i32 %inc, i32* @b, align 4 + br label %for.cond + +for.end: ; preds = %for.cond + ret i32 0 +} + +; Function Attrs: nounwind argmemonly +declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1) nounwind argmemonly + +; Function Attrs: noreturn nounwind +declare void @abort() noreturn nounwind