From 6052eef8bd701b30a0ab5749296671ca34389c39 Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Sun, 1 Apr 2012 10:21:05 +0000
Subject: [PATCH] Fix a pretty scary bug I introduced into the always inliner
 with a single missing character. Somehow, this had gone untested. I've added
 tests for returns-twice logic specifically with the always-inliner that would
 have caught this, and fixed the bug.

Thanks to Matt for the careful review and spotting this!!! =D

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153832 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/IPO/InlineAlways.cpp     |  2 +-
 test/Transforms/Inline/always-inline.ll | 38 +++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/lib/Transforms/IPO/InlineAlways.cpp b/lib/Transforms/IPO/InlineAlways.cpp
index a977027eed1..664ddf6f7a2 100644
--- a/lib/Transforms/IPO/InlineAlways.cpp
+++ b/lib/Transforms/IPO/InlineAlways.cpp
@@ -83,7 +83,7 @@ static bool isInlineViable(Function &F) {
 
       // Disallow calls which expose returns-twice to a function not previously
       // attributed as such.
-      if (ReturnsTwice && CS.isCall() &&
+      if (!ReturnsTwice && CS.isCall() &&
           cast<CallInst>(CS.getInstruction())->canReturnTwice())
         return false;
     }
diff --git a/test/Transforms/Inline/always-inline.ll b/test/Transforms/Inline/always-inline.ll
index 40091d7518a..bfd8762713d 100644
--- a/test/Transforms/Inline/always-inline.ll
+++ b/test/Transforms/Inline/always-inline.ll
@@ -40,3 +40,41 @@ define void @outer2(i32 %N) {
   call void @inner2( i32 %N )
   ret void
 }
+
+declare i32 @a() returns_twice
+declare i32 @b() returns_twice
+
+define i32 @inner3() alwaysinline {
+entry:
+  %call = call i32 @a() returns_twice
+  %add = add nsw i32 1, %call
+  ret i32 %add
+}
+define i32 @outer3() {
+entry:
+; CHECK: @outer3
+; CHECK-NOT: call i32 @a
+; CHECK: ret
+
+  %call = call i32 @inner3()
+  %add = add nsw i32 1, %call
+  ret i32 %add
+}
+
+define i32 @inner4() alwaysinline returns_twice {
+entry:
+  %call = call i32 @b() returns_twice
+  %add = add nsw i32 1, %call
+  ret i32 %add
+}
+
+define i32 @outer4() {
+entry:
+; CHECK: @outer4
+; CHECK: call i32 @b()
+; CHECK: ret
+
+  %call = call i32 @inner4() returns_twice
+  %add = add nsw i32 1, %call
+  ret i32 %add
+}