[MemorySSA] Don't use template when the clone is a simplified instruction.

Summary:
LoopRotate doesn't create a faithful clone of an instruction, it may
simplify it beforehand. Hence the clone of an instruction that has a
MemoryDef associated may not be a definition, but a use or not a memory
alternig instruction.
Don't rely on the template when the clone may be simplified.

Reviewers: george.burgess.iv

Subscribers: jlebar, Prazek, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63355

llvm-svn: 363597

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/test/Analysis/MemorySSA/loop-rotate-inv-template.ll b/llvm/test/Analysis/MemorySSA/loop-rotate-inv-template.ll
new file mode 100644
index 00000000000..ec2e8e6e841
--- /dev/null
+++ b/llvm/test/Analysis/MemorySSA/loop-rotate-inv-template.ll
@@ -0,0 +1,27 @@
+; RUN: opt -disable-output -loop-rotate -enable-mssa-loop-dependency -verify-memoryssa %s
+; REQUIRES: asserts
+
+; Function Attrs: nounwind
+define dso_local void @bar() local_unnamed_addr #0 align 32 {
+entry:
+  br label %looplabel.exit.i
+
+looplabel.exit.i: ; preds = %if.end.i, %entry
+  %0 = phi i1 (i32*, i32*)* [ @foo, %entry ], [ undef, %if.end.i ]
+  %call3.i.i = call zeroext i1 %0(i32* nonnull dereferenceable(16) undef, i32* nonnull undef)
+  br i1 %call3.i.i, label %if.end.i, label %label.exit
+
+if.end.i:                                         ; preds = %looplabel.exit.i
+  %tobool.i = icmp eq i32* undef, null
+  br label %looplabel.exit.i
+
+label.exit: ; preds = %looplabel.exit.i
+  ret void
+}
+
+; Function Attrs: readonly
+declare dso_local i1 @foo(i32*, i32*) #1 align 32
+
+attributes #0 = { nounwind }
+attributes #1 = { readonly }
+