[llvm] 99dcee6 - [MemorySSA] Add test for select with cross-iteration dependency (NFC)

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2022-10-14T11:03:02+02:00
New Revision: 99dcee6f504bcc84ca816febca72ad8b7281fe30

URL: https://github.com/llvm/llvm-project/commit/99dcee6f504bcc84ca816febca72ad8b7281fe30
DIFF: https://github.com/llvm/llvm-project/commit/99dcee6f504bcc84ca816febca72ad8b7281fe30.diff

LOG: [MemorySSA] Add test for select with cross-iteration dependency (NFC)

This is currently miscompiled.

Added: 
    llvm/test/Analysis/MemorySSA/select-loop-dep.ll

Modified: 
    

Removed: 
    


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diff  --git a/llvm/test/Analysis/MemorySSA/select-loop-dep.ll b/llvm/test/Analysis/MemorySSA/select-loop-dep.ll
new file mode 100644
index 0000000000000..3fb988a0f4d17
--- /dev/null
+++ b/llvm/test/Analysis/MemorySSA/select-loop-dep.ll
@@ -0,0 +1,30 @@
+; RUN: opt -passes='print<memoryssa>' -disable-output < %s 2>&1 | FileCheck %s
+
+; FIXME: The %sel2 load should be MemoryUse(4), because it loads the value
+; stored by the %sel1 store on the previous iteration.
+; CHECK: 1 = MemoryDef(liveOnEntry)
+; CHECK-NEXT: store i32 1, ptr %a1, align 4
+; CHECK: 2 = MemoryDef(1)
+; CHECK-NEXT: store i32 2, ptr %a2, align 4
+; CHECK: 4 = MemoryPhi({entry,2},{loop,3})
+; CHECK-NEXT: %c = phi i1 [ true, %entry ], [ false, %loop ]
+; CHECK: 3 = MemoryDef(4)
+; CHECK-NEXT: store i32 0, ptr %sel1, align 4
+; CHECK: MemoryUse(2)
+; CHECK-NEXT: %v = load i32, ptr %sel2, align 4
+define void @test() {
+entry:
+  %a1 = alloca i32
+  %a2 = alloca i32
+  store i32 1, ptr %a1
+  store i32 2, ptr %a2
+  br label %loop
+
+loop:
+  %c = phi i1 [ true, %entry ], [ false, %loop ]
+  %sel1 = select i1 %c, ptr %a1, ptr %a2
+  store i32 0, ptr %sel1
+  %sel2 = select i1 %c, ptr %a2, ptr %a1
+  %v = load i32, ptr %sel2
+  br label %loop
+}