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When eliminating unnecessary retain+autorelease on return values,

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handle the case where the retain is in a different basic block.
rdar://10210274.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140815 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2011-09-29 22:27:34 +00:00
parent 597fece886
commit 27e0666725
2 changed files with 61 additions and 1 deletions
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3
lib/Transforms/Scalar/ObjCARC.cpp
View File

@ -3198,7 +3198,8 @@ void ObjCARCOpt::OptimizeReturns(Function &F) {
// Check that there is nothing that can affect the reference
// count between the retain and the call.
FindDependencies(CanChangeRetainCount, Arg, BB, Retain,
// Note that Retain need not be in BB.
FindDependencies(CanChangeRetainCount, Arg, Retain->getParent(), Retain,
DependingInstructions, Visited, PA);
if (DependingInstructions.size() != 1)
goto next_block;

59
test/Transforms/ObjCARC/empty-block.ll Normal file
View File

@ -0,0 +1,59 @@
; RUN: opt -S -objc-arc < %s | FileCheck %s
; rdar://10210274
%0 = type opaque
declare i8* @objc_retain(i8*)
declare void @objc_release(i8*)
declare i8* @objc_autoreleaseReturnValue(i8*)
; Don't delete the autorelease.
; CHECK: define %0* @test0(
; CHECK: @objc_retain
; CHECK: .lr.ph:
; CHECK-NOT: @objc_r
; CHECK: @objc_autoreleaseReturnValue
; CHECK-NOT: @objc_
; CHECK: }
define %0* @test0(%0* %buffer) nounwind {
%1 = bitcast %0* %buffer to i8*
%2 = tail call i8* @objc_retain(i8* %1) nounwind
br i1 undef, label %.lr.ph, label %._crit_edge
.lr.ph: ; preds = %.lr.ph, %0
br i1 false, label %.lr.ph, label %._crit_edge
._crit_edge: ; preds = %.lr.ph, %0
%3 = tail call i8* @objc_retain(i8* %1) nounwind
tail call void @objc_release(i8* %1) nounwind, !clang.imprecise_release !0
%4 = tail call i8* @objc_autoreleaseReturnValue(i8* %1) nounwind
ret %0* %buffer
}
; Do delete the autorelease, even with the retain in a different block.
; CHECK: define %0* @test1(
; CHECK-NOT: @objc
; CHECK: }
define %0* @test1() nounwind {
%buffer = call %0* @foo()
%1 = bitcast %0* %buffer to i8*
%2 = tail call i8* @objc_retain(i8* %1) nounwind
br i1 undef, label %.lr.ph, label %._crit_edge
.lr.ph: ; preds = %.lr.ph, %0
br i1 false, label %.lr.ph, label %._crit_edge
._crit_edge: ; preds = %.lr.ph, %0
%3 = tail call i8* @objc_retain(i8* %1) nounwind
tail call void @objc_release(i8* %1) nounwind, !clang.imprecise_release !0
%4 = tail call i8* @objc_autoreleaseReturnValue(i8* %1) nounwind
ret %0* %buffer
}
declare %0* @foo()
!0 = metadata !{}