From 6ea4841da1390b4f76d066f25333f11f6d8c5f40 Mon Sep 17 00:00:00 2001
From: John McCall <rjmccall@apple.com>
Date: Thu, 26 Apr 2012 21:14:42 +0000
Subject: [PATCH] Fix a bug with block layout when the block contains something
 more aligned than the block header but also contains something smaller than
 the block-header alignment but not exactly half the difference between the
 large alignment and the header alignment.  Got that?

I'm really not sure what I was thinking with the buggy computation
here, but the fix is pretty obvious.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155662 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/CGBlocks.cpp | 13 ++++++++-----
 test/CodeGen/blocks.c    |  8 ++++++++
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/lib/CodeGen/CGBlocks.cpp b/lib/CodeGen/CGBlocks.cpp
index f8c7bcd4d7..379da11033 100644
--- a/lib/CodeGen/CGBlocks.cpp
+++ b/lib/CodeGen/CGBlocks.cpp
@@ -458,19 +458,22 @@ static void computeBlockInfo(CodeGenModule &CGM, CodeGenFunction *CGF,
     }
   }
 
+  assert(endAlign == getLowBit(blockSize));
+
   // At this point, we just have to add padding if the end align still
   // isn't aligned right.
   if (endAlign < maxFieldAlign) {
-    CharUnits padding = maxFieldAlign - endAlign;
+    CharUnits newBlockSize = blockSize.RoundUpToAlignment(maxFieldAlign);
+    CharUnits padding = newBlockSize - blockSize;
 
     elementTypes.push_back(llvm::ArrayType::get(CGM.Int8Ty,
                                                 padding.getQuantity()));
-    blockSize += padding;
-
-    endAlign = getLowBit(blockSize);
-    assert(endAlign >= maxFieldAlign);
+    blockSize = newBlockSize;
+    endAlign = maxFieldAlign;
   }
 
+  assert(endAlign == getLowBit(blockSize));
+
   // Slam everything else on now.  This works because they have
   // strictly decreasing alignment and we expect that size is always a
   // multiple of alignment.
diff --git a/test/CodeGen/blocks.c b/test/CodeGen/blocks.c
index bef44c3690..77fb0e1899 100644
--- a/test/CodeGen/blocks.c
+++ b/test/CodeGen/blocks.c
@@ -40,3 +40,11 @@ void f3() {
   _Bool b = 0;
   f3_helper(^{ if (b) {} });
 }
+
+// rdar://problem/11322251
+void f4_helper(long long (^)(void));
+void f4(void) {
+  _Bool b = 0;
+  long long ll = 0;
+  f4_helper(^{ if (b) return ll; return 0LL; });
+}
-- 
2.40.0