From: Nikita Popov <nikita.ppv@gmail.com>
Date: Thu, 21 Oct 2021 18:47:13 +0000 (+0200)
Subject: [InstCombine] Add additional store forwarding test (NFC)
X-Git-Tag: upstream/15.0.7~27999
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8262f45c73ae97de038e9b66ec5016938424123e;p=platform%2Fupstream%2Fllvm.git

[InstCombine] Add additional store forwarding test (NFC)

Variant where the load is larger than the store. Make sure we
don't forward this.
---

diff --git a/llvm/test/Transforms/InstCombine/load-store-forward.ll b/llvm/test/Transforms/InstCombine/load-store-forward.ll
index ab44a24..3dac00c 100644
--- a/llvm/test/Transforms/InstCombine/load-store-forward.ll
+++ b/llvm/test/Transforms/InstCombine/load-store-forward.ll
@@ -18,6 +18,20 @@ define i8 @load_smaller_int(i16* %p) {
   ret i8 %load
 }
 
+; This case can *not* be forwarded, as we only see part of the stored value.
+define i32 @load_larger_int(i16* %p) {
+; CHECK-LABEL: @load_larger_int(
+; CHECK-NEXT:    store i16 258, i16* [[P:%.*]], align 2
+; CHECK-NEXT:    [[P2:%.*]] = bitcast i16* [[P]] to i32*
+; CHECK-NEXT:    [[LOAD:%.*]] = load i32, i32* [[P2]], align 4
+; CHECK-NEXT:    ret i32 [[LOAD]]
+;
+  store i16 258, i16* %p
+  %p2 = bitcast i16* %p to i32*
+  %load = load i32, i32* %p2
+  ret i32 %load
+}
+
 define i32 @vec_store_load_first(i32* %p) {
 ; CHECK-LABEL: @vec_store_load_first(
 ; CHECK-NEXT:    [[P2:%.*]] = bitcast i32* [[P:%.*]] to <2 x i32>*