From e3ed2b0699a22cb986831c6f57da24c99419461f Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Fri, 23 Mar 2012 18:09:00 +0000
Subject: [PATCH] Don't convert objc_retainAutoreleasedReturnValue to
 objc_retain if it is retaining the return value of an invoke that it
 immediately follows.

llvm-svn: 153344
---
 llvm/lib/Transforms/Scalar/ObjCARC.cpp        | 13 +++++-
 llvm/test/Transforms/ObjCARC/invoke.ll        | 43 +++++++++++++++++++
 .../Transforms/ObjCARC/retain-not-declared.ll |  2 +-
 3 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/Transforms/Scalar/ObjCARC.cpp b/llvm/lib/Transforms/Scalar/ObjCARC.cpp
index b5f91716f88c..ab8cd4462540 100644
--- a/llvm/lib/Transforms/Scalar/ObjCARC.cpp
+++ b/llvm/lib/Transforms/Scalar/ObjCARC.cpp
@@ -2143,17 +2143,26 @@ ObjCARCOpt::OptimizeRetainCall(Function &F, Instruction *Retain) {
 /// return true.
 bool
 ObjCARCOpt::OptimizeRetainRVCall(Function &F, Instruction *RetainRV) {
-  // Check for the argument being from an immediately preceding call.
+  // Check for the argument being from an immediately preceding call or invoke.
   Value *Arg = GetObjCArg(RetainRV);
   CallSite CS(Arg);
-  if (Instruction *Call = CS.getInstruction())
+  if (Instruction *Call = CS.getInstruction()) {
     if (Call->getParent() == RetainRV->getParent()) {
       BasicBlock::iterator I = Call;
       ++I;
       while (isNoopInstruction(I)) ++I;
       if (&*I == RetainRV)
         return false;
+    } else if (InvokeInst *II = dyn_cast<InvokeInst>(Call)) {
+      BasicBlock *RetainRVParent = RetainRV->getParent();
+      if (II->getNormalDest() == RetainRVParent) {
+        BasicBlock::iterator I = RetainRVParent->begin();
+        while (isNoopInstruction(I)) ++I;
+        if (&*I == RetainRV)
+          return false;
+      }
     }
+  }
 
   // Check for being preceded by an objc_autoreleaseReturnValue on the same
   // pointer. In this case, we can delete the pair.
diff --git a/llvm/test/Transforms/ObjCARC/invoke.ll b/llvm/test/Transforms/ObjCARC/invoke.ll
index a852c4e4fbf6..76e82a587b8d 100644
--- a/llvm/test/Transforms/ObjCARC/invoke.ll
+++ b/llvm/test/Transforms/ObjCARC/invoke.ll
@@ -6,6 +6,7 @@ declare i8* @objc_retainAutoreleasedReturnValue(i8*)
 declare i8* @objc_msgSend(i8*, i8*, ...)
 declare void @use_pointer(i8*)
 declare void @callee()
+declare i8* @returner()
 
 ; ARCOpt shouldn't try to move the releases to the block containing the invoke.
 
@@ -169,6 +170,48 @@ if.end:
   ret void
 }
 
+; Don't turn the retainAutoreleaseReturnValue into retain, because it's
+; for an invoke which we can assume codegen will put immediately prior.
+
+; CHECK: define void @test5(
+; CHECK: call i8* @objc_retainAutoreleasedReturnValue(i8* %z)
+; CHECK: }
+define void @test5() {
+entry:
+  %z = invoke i8* @returner()
+          to label %if.end unwind label %lpad, !clang.arc.no_objc_arc_exceptions !0
+
+lpad:
+  %r13 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__objc_personality_v0 to i8*)
+          cleanup
+  ret void
+
+if.end:
+  call i8* @objc_retainAutoreleasedReturnValue(i8* %z)
+  ret void
+}
+
+; Like test5, but there's intervening code.
+
+; CHECK: define void @test6(
+; CHECK: call i8* @objc_retain(i8* %z)
+; CHECK: }
+define void @test6() {
+entry:
+  %z = invoke i8* @returner()
+          to label %if.end unwind label %lpad, !clang.arc.no_objc_arc_exceptions !0
+
+lpad:
+  %r13 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__objc_personality_v0 to i8*)
+          cleanup
+  ret void
+
+if.end:
+  call void @callee()
+  call i8* @objc_retainAutoreleasedReturnValue(i8* %z)
+  ret void
+}
+
 declare i32 @__gxx_personality_v0(...)
 declare i32 @__objc_personality_v0(...)
 
diff --git a/llvm/test/Transforms/ObjCARC/retain-not-declared.ll b/llvm/test/Transforms/ObjCARC/retain-not-declared.ll
index 41bde017e777..f876e51592b6 100644
--- a/llvm/test/Transforms/ObjCARC/retain-not-declared.ll
+++ b/llvm/test/Transforms/ObjCARC/retain-not-declared.ll
@@ -30,7 +30,7 @@ entry:
 
 ; CHECK: @test1(
 ; CHECK: @objc_retain(
-; CHECK: @objc_retain(
+; CHECK: @objc_retainAutoreleasedReturnValue(
 ; CHECK: @objc_release(
 ; CHECK: @objc_release(
 ; CHECK: }