From 4e9082ef95db5d760df4cce00a4351fa122176d6 Mon Sep 17 00:00:00 2001
From: Alina Sbirlea <asbirlea@google.com>
Date: Tue, 17 Sep 2019 16:33:35 +0000
Subject: [PATCH] [MemorySSA] Fix phi insertion when inserting a def.

Summary:
When inserting a Def, the current algorithm is walking edges backward
and inserting new Phis where needed. There may be additional Phis needed
in the IDF of the newly inserted Def and Phis.
Adding Phis in the IDF of the Def was added ina  previous patch, but we
may also need other Phis in the IDF of the newly added Phis.

Reviewers: george.burgess.iv

Subscribers: Prazek, sanjoy.google, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67637

llvm-svn: 372138
---
 llvm/lib/Analysis/MemorySSAUpdater.cpp  |  3 +++
 llvm/test/Analysis/MemorySSA/pr43320.ll | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)
 create mode 100644 llvm/test/Analysis/MemorySSA/pr43320.ll

diff --git a/llvm/lib/Analysis/MemorySSAUpdater.cpp b/llvm/lib/Analysis/MemorySSAUpdater.cpp
index b29be09..94417dc 100644
--- a/llvm/lib/Analysis/MemorySSAUpdater.cpp
+++ b/llvm/lib/Analysis/MemorySSAUpdater.cpp
@@ -339,6 +339,9 @@ void MemorySSAUpdater::insertDef(MemoryDef *MD, bool RenameUses) {
       ForwardIDFCalculator IDFs(*MSSA->DT);
       SmallVector<BasicBlock *, 32> IDFBlocks;
       SmallPtrSet<BasicBlock *, 2> DefiningBlocks;
+      for (const auto &VH : InsertedPHIs)
+        if (const auto *RealPHI = cast_or_null<MemoryPhi>(VH))
+          DefiningBlocks.insert(RealPHI->getBlock());
       DefiningBlocks.insert(MD->getBlock());
       IDFs.setDefiningBlocks(DefiningBlocks);
       IDFs.calculate(IDFBlocks);
diff --git a/llvm/test/Analysis/MemorySSA/pr43320.ll b/llvm/test/Analysis/MemorySSA/pr43320.ll
new file mode 100644
index 0000000..6aca3f9
--- /dev/null
+++ b/llvm/test/Analysis/MemorySSA/pr43320.ll
@@ -0,0 +1,33 @@
+; RUN: opt -licm -enable-mssa-loop-dependency -verify-memoryssa -S < %s | FileCheck %s
+; REQUIRES: asserts
+
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-unknown-none-eabi"
+
+; CHECK-LABEL: @e()
+define void @e() {
+entry:
+  br label %g
+
+g:                                                ; preds = %cleanup, %entry
+  %0 = load i32, i32* null, align 4
+  %and = and i32 %0, undef
+  store i32 %and, i32* null, align 4
+  br i1 undef, label %if.end8, label %if.then
+
+if.then:                                          ; preds = %g
+  br i1 undef, label %k, label %cleanup
+
+k:                                                ; preds = %if.end8, %if.then
+  br i1 undef, label %if.end8, label %cleanup
+
+if.end8:                                          ; preds = %k, %g
+  br i1 undef, label %for.cond.preheader, label %k
+
+for.cond.preheader:                               ; preds = %if.end8
+  unreachable
+
+cleanup:                                          ; preds = %k, %if.then
+  br label %g
+}
+
-- 
2.7.4