// Don't use GetArgRCIdentityRoot because we don't want to look through bitcasts
// and such; to do the replacement, the argument must have type i8*.
- Value *Arg = cast<CallInst>(Inst)->getArgOperand(0);
- // TODO: Change this to a do-while.
- for (;;) {
+ // Function for replacing uses of Arg dominated by Inst.
+ auto ReplaceArgUses = [Inst, this](Value *Arg) {
// If we're compiling bugpointed code, don't get in trouble.
if (!isa<Instruction>(Arg) && !isa<Argument>(Arg))
- break;
+ return;
+
// Look through the uses of the pointer.
for (Value::use_iterator UI = Arg->use_begin(), UE = Arg->use_end();
UI != UE; ) {
}
}
}
+ };
+
+
+ Value *Arg = cast<CallInst>(Inst)->getArgOperand(0), *OrigArg = Arg;
+
+ // TODO: Change this to a do-while.
+ for (;;) {
+ ReplaceArgUses(Arg);
// If Arg is a no-op casted pointer, strip one level of casts and iterate.
if (const BitCastInst *BI = dyn_cast<BitCastInst>(Arg))
else
break;
}
+
+ // Replace bitcast users of Arg that are dominated by Inst.
+ SmallVector<BitCastInst *, 2> BitCastUsers;
+
+ // Add all bitcast users of the function argument first.
+ for (User *U : OrigArg->users())
+ if (auto *BC = dyn_cast<BitCastInst>(U))
+ BitCastUsers.push_back(BC);
+
+ // Replace the bitcasts with the call return. Iterate until list is empty.
+ while (!BitCastUsers.empty()) {
+ auto *BC = BitCastUsers.pop_back_val();
+ for (User *U : BC->users())
+ if (auto *B = dyn_cast<BitCastInst>(U))
+ BitCastUsers.push_back(B);
+
+ ReplaceArgUses(BC);
+ }
}
// If this function has no escaping allocas or suspicious vararg usage,
--- /dev/null
+; RUN: opt -objc-arc-contract -S < %s | FileCheck %s
+
+declare i8* @objc_autoreleaseReturnValue(i8*)
+declare i8* @foo1()
+
+; Check that ARC contraction replaces the function return with the value
+; returned by @objc_autoreleaseReturnValue.
+
+; CHECK: %[[V0:[0-9]+]] = tail call i8* @objc_autoreleaseReturnValue(
+; CHECK: %[[V1:[0-9]+]] = bitcast i8* %[[V0]] to i32*
+; CHECK: ret i32* %[[V1]]
+
+define i32* @autoreleaseRVTailCall() {
+ %1 = call i8* @foo1()
+ %2 = bitcast i8* %1 to i32*
+ %3 = tail call i8* @objc_autoreleaseReturnValue(i8* %1)
+ ret i32* %2
+}