From 505359f705797548419bba8a849644db037bc027 Mon Sep 17 00:00:00 2001
From: Serguei Katkov <serguei.katkov@azul.com>
Date: Mon, 20 Nov 2017 05:42:36 +0000
Subject: [PATCH] [CGP] Fix the crash caused by enable of complex addr mode

We must collect all AddModes even if they are the same.
This is due to Original value is different but we need all original
values collected as they are used as anchors in common phi finding.

Reviewers: john.brawn, reames
Reviewed By: john.brawn
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D40166

llvm-svn: 318638
---
 llvm/lib/CodeGen/CodeGenPrepare.cpp                | 14 ++++-----
 .../CodeGenPrepare/X86/sink-addrmode-base.ll       | 35 ++++++++++++++++++++++
 2 files changed, 40 insertions(+), 9 deletions(-)

diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index ebdb853..e60e1e2 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -2800,15 +2800,11 @@ public:
     else if (DifferentField != ThisDifferentField)
       DifferentField = ExtAddrMode::MultipleFields;
 
-    // If this AddrMode is the same as all the others then everything is fine
-    // (which should only happen when there is actually only one AddrMode).
-    if (DifferentField == ExtAddrMode::NoField) {
-      assert(AddrModes.size() == 1);
-      return true;
-    }
-
     // If NewAddrMode differs in only one dimension then we can handle it by
-    // inserting a phi/select later on.
+    // inserting a phi/select later on. Even if NewAddMode is the same
+    // we still need to collect it due to original value is different.
+    // And later we will need all original values as anchors during
+    // finding the common Phi node.
     if (DifferentField != ExtAddrMode::MultipleFields) {
       AddrModes.emplace_back(NewAddrMode);
       return true;
@@ -2829,7 +2825,7 @@ public:
       return false;
 
     // A single AddrMode can trivially be combined.
-    if (AddrModes.size() == 1)
+    if (AddrModes.size() == 1 || DifferentField == ExtAddrMode::NoField)
       return true;
 
     // If the AddrModes we collected are all just equal to the value they are
diff --git a/llvm/test/Transforms/CodeGenPrepare/X86/sink-addrmode-base.ll b/llvm/test/Transforms/CodeGenPrepare/X86/sink-addrmode-base.ll
index 2bacbdd..f56f99c 100644
--- a/llvm/test/Transforms/CodeGenPrepare/X86/sink-addrmode-base.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/X86/sink-addrmode-base.ll
@@ -473,3 +473,38 @@ fallthrough:
   %v = load i64 , i64* %p1, align 8
   ret i64 %v
 }
+
+; The same two addr modes by different paths
+define i32 @test18(i1 %cond1, i1 %cond2, i64* %b1, i64* %b2) {
+; CHECK-LABEL: @test18
+entry:
+  %g1 = getelementptr inbounds i64, i64* %b2, i64 5
+  %bc1 = bitcast i64* %g1 to i32*
+  br i1 %cond1, label %if.then1, label %if.then2
+
+if.then1:
+  %g2 = getelementptr inbounds i64, i64* %b1, i64 5
+  %bc2 = bitcast i64* %g2 to i32*
+  br label %fallthrough
+
+if.then2:
+  %bc1_1 = bitcast i64* %g1 to i32*
+  br i1 %cond2, label %fallthrough, label %if.then3
+
+if.then3:
+  %bc1_2 = bitcast i64* %g1 to i32*
+  br label %fallthrough
+
+fallthrough:
+; CHECK-YES: sunk_phi
+; CHECK-NO-LABEL: fallthrough:
+; CHECK-NO: phi
+; CHECK-NO-NEXT: load
+  %c = phi i32* [%bc2, %if.then1], [%bc1_1, %if.then2], [%bc1_2, %if.then3]
+  %v1 = load i32, i32* %c, align 4
+  %g1_1 = getelementptr inbounds i64, i64* %b2, i64 5
+  %bc1_1_1 = bitcast i64* %g1_1 to i32*
+  %v2 = load i32, i32* %bc1_1_1, align 4
+  %v = add i32 %v1, %v2
+  ret i32 %v
+}
-- 
2.7.4