[llvm-commits] [llvm] r155160 - in /llvm/trunk: lib/Transforms/Scalar/ObjCARC.cpp test/Transforms/ObjCARC/split-backedge.ll

[Dan Gohman]

Author: djg
Date: Thu Apr 19 16:50:46 2012
New Revision: 155160

URL: http://llvm.org/viewvc/llvm-project?rev=155160&view=rev
Log:
Avoid a bug in the path count computation, preventing an infinite
loop repeatedlt making the same change. This is for rdar://11256239.

Added:
    llvm/trunk/test/Transforms/ObjCARC/split-backedge.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp?rev=155160&r1=155159&r2=155160&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/ObjCARC.cpp Thu Apr 19 16:50:46 2012
@@ -3379,7 +3379,7 @@
 
     // Ok, everything checks out and we're all set. Let's move some code!
     Changed = true;
-    AnyPairsCompletelyEliminated = NewCount == 0;
+    AnyPairsCompletelyEliminated = OldCount != 0 && NewCount == 0;
     NumRRs += OldCount - NewCount;
     MoveCalls(Arg, RetainsToMove, ReleasesToMove,
               Retains, Releases, DeadInsts, M);

Added: llvm/trunk/test/Transforms/ObjCARC/split-backedge.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ObjCARC/split-backedge.ll?rev=155160&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/ObjCARC/split-backedge.ll (added)
+++ llvm/trunk/test/Transforms/ObjCARC/split-backedge.ll Thu Apr 19 16:50:46 2012
@@ -0,0 +1,48 @@
+; RUN: opt -S -objc-arc < %s | FileCheck %s
+
+; Handle a retain+release pair entirely contained within a split loop backedge.
+; rdar://11256239
+
+; CHECK: define void @test0
+; CHECK: call i8* @objc_retain(i8* %call) nounwind
+; CHECK: call i8* @objc_retain(i8* %call) nounwind
+; CHECK: call i8* @objc_retain(i8* %cond) nounwind
+; CHECK: call void @objc_release(i8* %call) nounwind
+; CHECK: call void @objc_release(i8* %call) nounwind
+; CHECK: call void @objc_release(i8* %cond) nounwind
+define void @test0() {
+entry:
+  br label %while.body
+
+while.body:                                       ; preds = %while.cond
+  %call = invoke i8* @returner()
+          to label %invoke.cont unwind label %lpad, !clang.arc.no_objc_arc_exceptions !0
+
+invoke.cont:                                      ; preds = %while.body
+  %t0 = call i8* @objc_retain(i8* %call) nounwind
+  %t1 = call i8* @objc_retain(i8* %call) nounwind
+  %call.i1 = invoke i8* @returner()
+          to label %invoke.cont1 unwind label %lpad
+
+invoke.cont1:                                     ; preds = %invoke.cont
+  %cond = select i1 undef, i8* null, i8* %call
+  %t2 = call i8* @objc_retain(i8* %cond) nounwind
+  call void @objc_release(i8* %call) nounwind
+  call void @objc_release(i8* %call) nounwind
+  call void @use_pointer(i8* %cond)
+  call void @objc_release(i8* %cond) nounwind
+  br label %while.body
+
+lpad:                                             ; preds = %invoke.cont, %while.body
+  %t4 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__objc_personality_v0 to i8*)
+          catch i8* null
+  ret void
+}
+
+declare i8* @returner()
+declare i32 @__objc_personality_v0(...)
+declare void @objc_release(i8*)
+declare i8* @objc_retain(i8*)
+declare void @use_pointer(i8*)
+
+!0 = metadata !{}