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llvm-mirror/test/Transforms/ObjCARC/opt-catchswitch.ll
Akira Hatanaka b7e85bfcf7 [ObjC][ARC] In HandlePotentialAlterRefCount, check whether an
instruction can decrement the reference count, not whether it can alter
it

This prevents the state transition from S_Use to S_CanRelease when doing
a bottom-up traversal and the transition from S_Retain to S_CanRelease
when doing a top-down traversal when the visited instruction can
increment the ref count but cannot decrement it. This allows the ARC
optimizer to remove retain/release pairs which were previously not
removed.

rdar://problem/21793154
2020-08-28 17:45:14 -07:00

59 lines
2.0 KiB
LLVM

; RUN: opt -S -objc-arc < %s | FileCheck %s
target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
target triple = "i686--windows-msvc"
declare i8* @f(i8*, i8*)
declare i32 @__CxxFrameHandler3(...)
declare dllimport i8* @llvm.objc.autoreleaseReturnValue(i8* returned)
declare dllimport i8* @llvm.objc.retain(i8* returned)
declare dllimport i8* @llvm.objc.retainAutoreleasedReturnValue(i8* returned)
declare dllimport void @llvm.objc.release(i8*)
define i8* @g(i8* %p, i8* %q) local_unnamed_addr personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
entry:
%0 = tail call i8* @llvm.objc.retain(i8* %p) #0
; the following call prevents ARC optimizer from removing the retain/release
; pair on %p
%v1 = call i8* @f(i8* null, i8* null)
%1 = tail call i8* @llvm.objc.retain(i8* %q) #0
%call = invoke i8* @f(i8* %p, i8* %q)
to label %invoke.cont unwind label %catch.dispatch, !clang.arc.no_objc_arc_exceptions !0
catch.dispatch:
%2 = catchswitch within none [label %catch] unwind to caller
catch:
%3 = catchpad within %2 [i8* null, i32 64, i8* null]
catchret from %3 to label %cleanup
invoke.cont:
%4 = tail call i8* @llvm.objc.retainAutoreleasedReturnValue(i8* %call) #0
br label %cleanup
cleanup:
%retval.0 = phi i8* [ %call, %invoke.cont ], [ null, %catch ]
tail call void @llvm.objc.release(i8* %q) #0, !clang.imprecise_release !0
tail call void @llvm.objc.release(i8* %p) #0, !clang.imprecise_release !0
%5 = tail call i8* @llvm.objc.autoreleaseReturnValue(i8* %retval.0) #0
ret i8* %retval.0
}
; CHECK-LABEL: entry:
; CHECK-NEXT: %0 = tail call i8* @llvm.objc.retain(i8* %p) #0
; CHECK-NEXT: call i8* @f(i8* null, i8* null)
; CHECK-NEXT: %call = invoke i8* @f(i8* %p, i8* %q)
; CHECK-NEXT: to label %invoke.cont unwind label %catch.dispatch
; CHECK-LABEL: catch.dispatch:
; CHECK-NEXT: %1 = catchswitch within none [label %catch] unwind to caller
; CHECK-LABEL: cleanup:
; CHECK: tail call void @llvm.objc.release(i8* %p) #0
attributes #0 = { nounwind }
!0 = !{}