[llvm] ObjCARC: Drop pointer bitcast handling (PR #134274)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm created https://github.com/llvm/llvm-project/pull/134274

There is more in the file to drop, but this looks like the easier
part.

>From 14866ada8db7e99da2674dd4a247c246a7ae7e2a Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Thu, 3 Apr 2025 23:45:52 +0700
Subject: [PATCH] ObjCARC: Drop pointer bitcast handling

There is more in the file to drop, but this looks like the easier
part.
---
 .../Transforms/ObjCARC/ObjCARCContract.cpp    | 19 -------------------
 1 file changed, 19 deletions(-)

diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
index 311d3b1cfc0a0..e11748b2c9dbb 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCContract.cpp
@@ -660,7 +660,6 @@ bool ObjCARCContract::run(Function &F, AAResults *A, DominatorTree *D) {
     };
 
     Value *Arg = cast<CallInst>(Inst)->getArgOperand(0);
-    Value *OrigArg = Arg;
 
     // TODO: Change this to a do-while.
     for (;;) {
@@ -687,24 +686,6 @@ bool ObjCARCContract::run(Function &F, AAResults *A, DominatorTree *D) {
         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,