Fix aliasing of launder.invariant.group

Summary:
Patch for capture tracking broke
bootstrap of clang with -fstict-vtable-pointers
which resulted in debbugging nightmare. It was fixed
https://reviews.llvm.org/D46900 but as it turned
out, there were other parts like inliner (computing of
noalias metadata) that I found after bootstraping with enabled
assertions.

Reviewers: hfinkel, rsmith, chandlerc, amharc, kuhar

Subscribers: JDevlieghere, eraman, llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D47088

llvm-svn: 333070

1 files changed, 31 insertions, 0 deletions

diff --git a/llvm/test/Transforms/Inline/launder.invariant.group.ll b/llvm/test/Transforms/Inline/launder.invariant.group.ll
new file mode 100644
index 00000000000..a11475fdb57
--- /dev/null
+++ b/llvm/test/Transforms/Inline/launder.invariant.group.ll
@@ -0,0 +1,31 @@
+; RUN: opt -S -inline < %s | FileCheck %s
+; RUN: opt -S -O3 < %s | FileCheck %s
+
+; This test checks if value returned from the launder is considered aliasing
+; with its argument.  Due to bug caused by handling launder in capture tracking
+; sometimes it would be considered noalias.
+
+%struct.A = type <{ i32 (...)**, i32, [4 x i8] }>
+
+; CHECK: define i32 @bar(%struct.A* noalias
+define i32 @bar(%struct.A* noalias) {
+; CHECK-NOT: noalias
+  %2 = bitcast %struct.A* %0 to i8*
+  %3 = call i8* @llvm.launder.invariant.group.p0i8(i8* %2)
+  %4 = getelementptr inbounds i8, i8* %3, i64 8
+  %5 = bitcast i8* %4 to i32*
+  store i32 42, i32* %5, align 8
+  %6 = getelementptr inbounds %struct.A, %struct.A* %0, i64 0, i32 1
+  %7 = load i32, i32* %6, align 8
+  ret i32 %7
+}
+
+; CHECK-LABEL: define i32 @foo(%struct.A* noalias
+define i32 @foo(%struct.A* noalias)  {
+  ; CHECK-NOT: call i32 @bar(
+  ; CHECK-NOT: noalias
+  %2 = tail call i32 @bar(%struct.A* %0)
+  ret i32 %2
+}
+
+declare i8* @llvm.launder.invariant.group.p0i8(i8*)