perform DSE through launder.invariant.group
Summary:
Alias Analysis knows that llvm.launder.invariant.group
returns pointer that mustalias argument, but this information
wasn't used, therefor we didn't DSE through launder.invariant.group
Reviewers: chandlerc, dberlin, bogner, hfinkel, efriedma
Reviewed By: dberlin
Subscribers: amharc, llvm-commits, nlewycky, rsmith
Differential Revision: https://reviews.llvm.org/D31581
llvm-svn: 331449
diff --git a/llvm/test/Transforms/DeadStoreElimination/launder.invariant.group.ll b/llvm/test/Transforms/DeadStoreElimination/launder.invariant.group.ll
new file mode 100644
index 0000000..dfa316e
--- /dev/null
+++ b/llvm/test/Transforms/DeadStoreElimination/launder.invariant.group.ll
@@ -0,0 +1,30 @@
+; RUN: opt < %s -basicaa -dse -S | FileCheck %s
+
+; CHECK-LABEL: void @skipBarrier(i8* %ptr)
+define void @skipBarrier(i8* %ptr) {
+; CHECK-NOT: store i8 42
+ store i8 42, i8* %ptr
+; CHECK: %ptr2 = call i8* @llvm.launder.invariant.group.p0i8(i8* %ptr)
+ %ptr2 = call i8* @llvm.launder.invariant.group.p0i8(i8* %ptr)
+; CHECK: store i8 43
+ store i8 43, i8* %ptr2
+ ret void
+}
+
+; CHECK-LABEL: void @skip2Barriers(i8* %ptr)
+define void @skip2Barriers(i8* %ptr) {
+; CHECK-NOT: store i8 42
+ store i8 42, i8* %ptr
+; CHECK: %ptr2 = call i8* @llvm.launder.invariant.group.p0i8(i8* %ptr)
+ %ptr2 = call i8* @llvm.launder.invariant.group.p0i8(i8* %ptr)
+; CHECK-NOT: store i8 43
+ store i8 43, i8* %ptr2
+ %ptr3 = call i8* @llvm.launder.invariant.group.p0i8(i8* %ptr2)
+ %ptr4 = call i8* @llvm.launder.invariant.group.p0i8(i8* %ptr3)
+
+; CHECK: store i8 44
+ store i8 44, i8* %ptr4
+ ret void
+}
+
+declare i8* @llvm.launder.invariant.group.p0i8(i8*)