From: Florian Hahn <flo@fhahn.com>
Date: Wed, 27 Oct 2021 10:15:58 +0000 (+0100)
Subject: [DSE] Add test case with 2 memcpys that should not be eliminated.
X-Git-Tag: upstream/15.0.7~27520
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1a2a7cca3e43dc9e9c5f180a8cd2cbe32e1498da;p=platform%2Fupstream%2Fllvm.git

[DSE] Add test case with 2 memcpys that should not be eliminated.
---

diff --git a/llvm/test/Transforms/DeadStoreElimination/stores-of-existing-values.ll b/llvm/test/Transforms/DeadStoreElimination/stores-of-existing-values.ll
index 509d4e9..0380e80a 100644
--- a/llvm/test/Transforms/DeadStoreElimination/stores-of-existing-values.ll
+++ b/llvm/test/Transforms/DeadStoreElimination/stores-of-existing-values.ll
@@ -503,3 +503,20 @@ define void @pr50339(i8* nocapture readonly %0) {
   tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* noundef nonnull align 16 dereferenceable(16) getelementptr inbounds ([32 x i8], [32 x i8]* @a, i64 0, i64 0), i8* noundef nonnull align 1 dereferenceable(16) %0, i64 16, i1 false)
   ret void
 }
+
+; Cannot remove the second memcpy as redundant store, because %src is modified
+; in between.
+define i8 @memset_optimized_access(i8* noalias %dst, i8* noalias %src) {
+; CHECK-LABEL: @memset_optimized_access(
+; CHECK-NEXT:    tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[DST:%.*]], i8* [[SRC:%.*]], i64 16, i1 false)
+; CHECK-NEXT:    store i8 99, i8* [[SRC]], align 1
+; CHECK-NEXT:    [[L:%.*]] = load i8, i8* [[DST]], align 1
+; CHECK-NEXT:    tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[DST]], i8* [[SRC]], i64 16, i1 false)
+; CHECK-NEXT:    ret i8 [[L]]
+;
+  tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64 16, i1 false)
+  store i8 99, i8* %src
+  %l = load i8, i8* %dst
+  tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst, i8* %src, i64 16, i1 false)
+  ret i8 %l
+}