From 5f725cd1968c88e05f1c5b13a8187db8fa821cd7 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Mon, 25 Jun 2012 19:47:37 +0000
Subject: Fix the objc_autoreleasedReturnValue optimization code to locate the
 call correctly even in the case where it is an invoke. This fixes
 rdar://11714057.

llvm-svn: 159157
---
 llvm/lib/Transforms/Scalar/ObjCARC.cpp | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

(limited to 'llvm/lib')

diff --git a/llvm/lib/Transforms/Scalar/ObjCARC.cpp b/llvm/lib/Transforms/Scalar/ObjCARC.cpp
index d89996a1ff6..87e17c7f90a 100644
--- a/llvm/lib/Transforms/Scalar/ObjCARC.cpp
+++ b/llvm/lib/Transforms/Scalar/ObjCARC.cpp
@@ -4064,8 +4064,22 @@ bool ObjCARCContract::runOnFunction(Function &F) {
       if (!RetainRVMarker)
         break;
       BasicBlock::iterator BBI = Inst;
-      --BBI;
-      while (isNoopInstruction(BBI)) --BBI;
+      BasicBlock *InstParent = Inst->getParent();
+
+      // Step up to see if the call immediately precedes the RetainRV call.
+      // If it's an invoke, we have to cross a block boundary. And we have
+      // to carefully dodge no-op instructions.
+      do {
+        if (&*BBI == InstParent->begin()) {
+          BasicBlock *Pred = InstParent->getSinglePredecessor();
+          if (!Pred)
+            goto decline_rv_optimization;
+          BBI = Pred->getTerminator();
+          break;
+        }
+        --BBI;
+      } while (isNoopInstruction(BBI));
+
       if (&*BBI == GetObjCArg(Inst)) {
         Changed = true;
         InlineAsm *IA =
@@ -4075,6 +4089,7 @@ bool ObjCARCContract::runOnFunction(Function &F) {
                          /*Constraints=*/"", /*hasSideEffects=*/true);
         CallInst::Create(IA, "", Inst);
       }
+    decline_rv_optimization:
       break;
     }
     case IC_InitWeak: {
-- 
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