[llvm] ffd982f - [ObjC][ARC] Fix a bug where the inline-asm retain/claim RV marker wasn't

[Akira Hatanaka via llvm-commits]

Author: Akira Hatanaka
Date: 2020-12-18T16:59:06-08:00
New Revision: ffd982f7db58acf6653f987ca6411712feea25c3

URL: https://github.com/llvm/llvm-project/commit/ffd982f7db58acf6653f987ca6411712feea25c3
DIFF: https://github.com/llvm/llvm-project/commit/ffd982f7db58acf6653f987ca6411712feea25c3.diff

LOG: [ObjC][ARC] Fix a bug where the inline-asm retain/claim RV marker wasn't
inserted when the original call had a 'returned' argument

The code is testing whether the instruction BBI points to is the call
that is paired up with the retainRV/claimRV call, but it doesn't work
when the call has a 'returned' argument since GetArgRCIdentityRoot looks
through 'returned' arguments.

rdar://72485383

Added: 
    

Modified: 
    llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
    llvm/test/Transforms/ObjCARC/contract-marker.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
index e190c46b613b..c2499fc85cf5 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
@@ -476,7 +476,7 @@ bool ObjCARCContract::tryToPeepholeInstruction(
       --BBI;
     } while (IsNoopInstruction(&*BBI));
 
-    if (&*BBI == GetArgRCIdentityRoot(Inst)) {
+    if (GetRCIdentityRoot(&*BBI) == GetArgRCIdentityRoot(Inst)) {
       LLVM_DEBUG(dbgs() << "Adding inline asm marker for the return value "
                            "optimization.\n");
       Changed = true;

diff  --git a/llvm/test/Transforms/ObjCARC/contract-marker.ll b/llvm/test/Transforms/ObjCARC/contract-marker.ll
index a93bbe3a2901..e2217068d5d1 100644
--- a/llvm/test/Transforms/ObjCARC/contract-marker.ll
+++ b/llvm/test/Transforms/ObjCARC/contract-marker.ll
@@ -32,11 +32,31 @@ entry:
   ret void
 }
 
+; CHECK-LABEL: define i8* @foo3(
+; CHECK: call i8* @returnsArg(
+; CHECK-NEXT: call void asm sideeffect
+
+define i8* @foo3(i8* %a) {
+  %call = call i8* @returnsArg(i8* %a)
+  call i8* @llvm.objc.retainAutoreleasedReturnValue(i8* %call)
+  ret i8* %call
+}
+
+; CHECK-LABEL: define i8* @foo4(
+; CHECK: call i8* @returnsArg(
+; CHECK-NEXT: call void asm sideeffect
+
+define i8* @foo4(i8* %a) {
+  %call = call i8* @returnsArg(i8* %a)
+  call i8* @llvm.objc.retainAutoreleasedReturnValue(i8* %a)
+  ret i8* %call
+}
 
 declare i32* @qux()
 declare i8* @llvm.objc.retainAutoreleasedReturnValue(i8*)
 declare i8* @llvm.objc.unsafeClaimAutoreleasedReturnValue(i8*)
 declare void @bar(i8*)
+declare i8* @returnsArg(i8* returned)
 
 !llvm.module.flags = !{!0}