objc_retainBlock is not NoModRef because it can update forwarding pointers

in memory relevant to the optimizer. rdar://10050579.

llvm-svn: 139708
This commit is contained in:
Dan Gohman 2011-09-14 18:13:00 +00:00
parent 41c8bdfdd9
commit 223fdfc56f
2 changed files with 41 additions and 1 deletions

View File

@ -746,7 +746,6 @@ ObjCARCAliasAnalysis::getModRefInfo(ImmutableCallSite CS, const Location &Loc) {
switch (GetBasicInstructionClass(CS.getInstruction())) {
case IC_Retain:
case IC_RetainRV:
case IC_RetainBlock:
case IC_Autorelease:
case IC_AutoreleaseRV:
case IC_NoopCast:
@ -754,6 +753,8 @@ ObjCARCAliasAnalysis::getModRefInfo(ImmutableCallSite CS, const Location &Loc) {
case IC_FusedRetainAutorelease:
case IC_FusedRetainAutoreleaseRV:
// These functions don't access any memory visible to the compiler.
// Note that this doesn't include objc_retainBlock, becuase it updates
// pointers when it copies block data.
return NoModRef;
default:
break;

View File

@ -0,0 +1,39 @@
; RUN: opt -S -objc-arc-aa -basicaa -gvn < %s | FileCheck %s
; rdar://10050579
; objc_retainBlock stores into %repeater so the load from after the
; call isn't forwardable from the store before the call.
; CHECK: %tmp16 = call i8* @objc_retainBlock(i8* %tmp15) nounwind
; CHECK: %tmp17 = bitcast i8* %tmp16 to void ()*
; CHECK: %tmp18 = load %struct.__block_byref_repeater** %byref.forwarding, align 8
; CHECK: %repeater12 = getelementptr inbounds %struct.__block_byref_repeater* %tmp18, i64 0, i32 6
; CHECK: store void ()* %tmp17, void ()** %repeater12, align 8
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
%0 = type opaque
%struct.__block_byref_repeater = type { i8*, %struct.__block_byref_repeater*, i32, i32, i8*, i8*, void ()* }
%struct.__block_descriptor = type { i64, i64 }
define void @foo() noreturn {
entry:
%repeater = alloca %struct.__block_byref_repeater, align 8
%block = alloca <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0*, i8* }>, align 8
%byref.forwarding = getelementptr inbounds %struct.__block_byref_repeater* %repeater, i64 0, i32 1
%tmp10 = getelementptr inbounds %struct.__block_byref_repeater* %repeater, i64 0, i32 6
store void ()* null, void ()** %tmp10, align 8
%block.captured11 = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0*, i8* }>* %block, i64 0, i32 6
%tmp14 = bitcast %struct.__block_byref_repeater* %repeater to i8*
store i8* %tmp14, i8** %block.captured11, align 8
%tmp15 = bitcast <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0*, i8* }>* %block to i8*
%tmp16 = call i8* @objc_retainBlock(i8* %tmp15) nounwind
%tmp17 = bitcast i8* %tmp16 to void ()*
%tmp18 = load %struct.__block_byref_repeater** %byref.forwarding, align 8
%repeater12 = getelementptr inbounds %struct.__block_byref_repeater* %tmp18, i64 0, i32 6
%tmp13 = load void ()** %repeater12, align 8
store void ()* %tmp17, void ()** %repeater12, align 8
ret void
}
declare i8* @objc_retainBlock(i8*)