Teach the ARC optimizer about the !clang.arc.copy_on_escape metadata

tag on objc_retainBlock calls, which indicates that they may be
optimized away. rdar://10211286.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142298 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 41 insertions, 5 deletions

diff --git a/test/Transforms/ObjCARC/retain-block-alloca.ll b/test/Transforms/ObjCARC/retain-block-alloca.ll
index 468da91..01f2087 100644
--- a/test/Transforms/ObjCARC/retain-block-alloca.ll
+++ b/test/Transforms/ObjCARC/retain-block-alloca.ll
@@ -1,11 +1,6 @@
 ; RUN: opt -S -objc-arc < %s | FileCheck %s
 ; rdar://10209613
 
-; CHECK: define void @test
-; CHECK: %3 = call i8* @objc_retainBlock(i8* %2) nounwind
-; CHECK: @objc_msgSend
-; CHECK-NEXT: @objc_release(i8* %3)
-
 %0 = type opaque
 %struct.__block_descriptor = type { i64, i64 }
 
@@ -13,6 +8,10 @@
 @__block_descriptor_tmp = external hidden constant { i64, i64, i8*, i8*, i8*, i8* }
 @"\01L_OBJC_SELECTOR_REFERENCES_" = external hidden global i8*, section "__DATA, __objc_selrefs, literal_pointers, no_dead_strip"
 
+; CHECK: define void @test(
+; CHECK: %3 = call i8* @objc_retainBlock(i8* %2) nounwind
+; CHECK: @objc_msgSend
+; CHECK-NEXT: @objc_release(i8* %3)
 define void @test(%0* %array) uwtable {
 entry:
   %block = alloca <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>, align 8
@@ -41,6 +40,43 @@ entry:
   ret void
 }
 
+; Same as test, but the objc_retainBlock has a clang.arc.copy_on_escape
+; tag so it's safe to delete.
+
+; CHECK: define void @test_with_COE(
+; CHECK-NOT: @objc_retainBlock
+; CHECK: @objc_msgSend
+; CHECK: @objc_release
+; CHECK-NOT: @objc_release
+; CHECK: }
+define void @test_with_COE(%0* %array) uwtable {
+entry:
+  %block = alloca <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>, align 8
+  %0 = bitcast %0* %array to i8*
+  %1 = tail call i8* @objc_retain(i8* %0) nounwind
+  %block.isa = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i64 0, i32 0
+  store i8* bitcast (i8** @_NSConcreteStackBlock to i8*), i8** %block.isa, align 8
+  %block.flags = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i64 0, i32 1
+  store i32 1107296256, i32* %block.flags, align 8
+  %block.reserved = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i64 0, i32 2
+  store i32 0, i32* %block.reserved, align 4
+  %block.invoke = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i64 0, i32 3
+  store i8* bitcast (void (i8*)* @__test_block_invoke_0 to i8*), i8** %block.invoke, align 8
+  %block.descriptor = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i64 0, i32 4
+  store %struct.__block_descriptor* bitcast ({ i64, i64, i8*, i8*, i8*, i8* }* @__block_descriptor_tmp to %struct.__block_descriptor*), %struct.__block_descriptor** %block.descriptor, align 8
+  %block.captured = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block, i64 0, i32 5
+  store %0* %array, %0** %block.captured, align 8
+  %2 = bitcast <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, %0* }>* %block to i8*
+  %3 = call i8* @objc_retainBlock(i8* %2) nounwind, !clang.arc.copy_on_escape !0
+  %tmp2 = load i8** @"\01L_OBJC_SELECTOR_REFERENCES_", align 8
+  call void bitcast (i8* (i8*, i8*, ...)* @objc_msgSend to void (i8*, i8*, i8*)*)(i8* %0, i8* %tmp2, i8* %3)
+  call void @objc_release(i8* %3) nounwind
+  %strongdestroy = load %0** %block.captured, align 8
+  %4 = bitcast %0* %strongdestroy to i8*
+  call void @objc_release(i8* %4) nounwind, !clang.imprecise_release !0
+  ret void
+}
+
 declare i8* @objc_retain(i8*)
 
 declare void @__test_block_invoke_0(i8* nocapture) uwtable