NewGVN: Fix PR 31573, a failure to verify memory congruency due to

not excluding ourselves when checking if any equivalent stores
exist.

llvm-svn: 291421

1 files changed, 42 insertions, 0 deletions

diff --git a/llvm/test/Transforms/NewGVN/pr31573.ll b/llvm/test/Transforms/NewGVN/pr31573.ll
new file mode 100644
index 00000000000..0450b4b1299
--- /dev/null
+++ b/llvm/test/Transforms/NewGVN/pr31573.ll
@@ -0,0 +1,42 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -basicaa -newgvn -S | FileCheck %s
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @patatino(i8* %blah) {
+; CHECK-LABEL: @patatino(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[WHILE_COND:%.*]]
+; CHECK:       while.cond:
+; CHECK-NEXT:    [[MEH:%.*]] = phi i8* [ [[BLAH:%.*]], [[ENTRY:%.*]] ], [ null, [[WHILE_BODY:%.*]] ]
+; CHECK-NEXT:    switch i32 undef, label [[WHILE_BODY]] [
+; CHECK-NEXT:    i32 666, label [[WHILE_END:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       while.body:
+; CHECK-NEXT:    br label [[WHILE_COND]]
+; CHECK:       while.end:
+; CHECK-NEXT:    store i8 0, i8* [[MEH]], align 1
+; CHECK-NEXT:    store i8 0, i8* [[BLAH]], align 1
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %while.cond
+
+while.cond:
+  %meh = phi i8* [ %blah, %entry ], [ null, %while.body ]
+  switch i32 undef, label %while.body [
+  i32 666, label %while.end
+  ]
+
+while.body:
+  br label %while.cond
+
+while.end:
+;; These two stores will initially be considered equivalent, but then proven not.
+;; the second store would previously end up deciding it's equivalent to a previous
+;; store, but it was really just finding an optimistic version of itself
+;; in the congruence class.
+  store i8 0, i8* %meh, align 1
+  store i8 0, i8* %blah, align 1
+  ret void
+}