[llvm] InstCombine: Remove a check for pointer bitcasts (PR #128491)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm updated https://github.com/llvm/llvm-project/pull/128491

>From 62d9df3c2c7a7e6f44e64b6d3e0f58cb9b19a359 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Mon, 24 Feb 2025 18:07:59 +0700
Subject: [PATCH 1/3] InstCombine: Remove a check for pointer bitcasts

---
 llvm/lib/Transforms/InstCombine/InstructionCombining.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 81b057c10b484..90cb499947601 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -3661,8 +3661,7 @@ Instruction *InstCombinerImpl::visitUnconditionalBranchInst(BranchInst &BI) {
 
   auto GetLastSinkableStore = [](BasicBlock::iterator BBI) {
     auto IsNoopInstrForStoreMerging = [](BasicBlock::iterator BBI) {
-      return BBI->isDebugOrPseudoInst() ||
-             (isa<BitCastInst>(BBI) && BBI->getType()->isPointerTy());
+      return BBI->isDebugOrPseudoInst();
     };
 
     BasicBlock::iterator FirstInstr = BBI->getParent()->begin();

>From ba237ae60e3f2c8db7192a0ae27893d6f5bbe794 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Mon, 24 Feb 2025 18:47:15 +0700
Subject: [PATCH 2/3] Update comment

---
 llvm/lib/Transforms/InstCombine/InstructionCombining.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 90cb499947601..e052da8a57943 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -3656,7 +3656,7 @@ Instruction *InstCombinerImpl::visitUnconditionalBranchInst(BranchInst &BI) {
   assert(BI.isUnconditional() && "Only for unconditional branches.");
 
   // If this store is the second-to-last instruction in the basic block
-  // (excluding debug info and bitcasts of pointers) and if the block ends with
+  // (excluding debug info) and if the block ends with
   // an unconditional branch, try to move the store to the successor block.
 
   auto GetLastSinkableStore = [](BasicBlock::iterator BBI) {

>From 9d870a24e4681b929b8a88be1e548a83797d7356 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Mon, 24 Feb 2025 18:48:34 +0700
Subject: [PATCH 3/3] Inline lambda

---
 llvm/lib/Transforms/InstCombine/InstructionCombining.cpp | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index e052da8a57943..4c14dcfb4d75f 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -3660,15 +3660,11 @@ Instruction *InstCombinerImpl::visitUnconditionalBranchInst(BranchInst &BI) {
   // an unconditional branch, try to move the store to the successor block.
 
   auto GetLastSinkableStore = [](BasicBlock::iterator BBI) {
-    auto IsNoopInstrForStoreMerging = [](BasicBlock::iterator BBI) {
-      return BBI->isDebugOrPseudoInst();
-    };
-
     BasicBlock::iterator FirstInstr = BBI->getParent()->begin();
     do {
       if (BBI != FirstInstr)
         --BBI;
-    } while (BBI != FirstInstr && IsNoopInstrForStoreMerging(BBI));
+    } while (BBI != FirstInstr && BBI->isDebugOrPseudoInst());
 
     return dyn_cast<StoreInst>(BBI);
   };