[llvm] [BPI] Use BasicBlock::isEHPad() to check exception handling block. (PR #95771)

[via llvm-commits]

https://github.com/Enna1 created https://github.com/llvm/llvm-project/pull/95771

There is no need to iterate all predecessors of current block, check if current block is the invoke unwind destination of any predcessor. We can directly call `BasicBlock::isEHPad()` to check if current block is a exception handling block.

>From 70de50502959800622f0b0009ca74dc95084038b Mon Sep 17 00:00:00 2001
From: "xumingjie.enna1" <xumingjie.enna1 at bytedance.com>
Date: Fri, 14 Jun 2024 10:18:29 +0800
Subject: [PATCH] [BPI] Use BasicBlock::isEHPad() to check exception handling
 block.

There is no need to iterate all predecessors of current block, check if
current block is the invoke unwind destination of any predcessor.
We can directly call `BasicBlock::isEHPad()` to check if current block
is a exception handling block.
---
 llvm/lib/Analysis/BranchProbabilityInfo.cpp | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/llvm/lib/Analysis/BranchProbabilityInfo.cpp b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
index 50dcd5f45233f..3e9c60918f3c0 100644
--- a/llvm/lib/Analysis/BranchProbabilityInfo.cpp
+++ b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
@@ -787,12 +787,9 @@ BranchProbabilityInfo::getInitialEstimatedBlockWeight(const BasicBlock *BB) {
                ? static_cast<uint32_t>(BlockExecWeight::NORETURN)
                : static_cast<uint32_t>(BlockExecWeight::UNREACHABLE);
 
-  // Check if the block is 'unwind' handler of  some invoke instruction.
-  for (const auto *Pred : predecessors(BB))
-    if (Pred)
-      if (const auto *II = dyn_cast<InvokeInst>(Pred->getTerminator()))
-        if (II->getUnwindDest() == BB)
-          return static_cast<uint32_t>(BlockExecWeight::UNWIND);
+  // Check if the block is an exception handling block.
+  if (BB->isEHPad())
+    return static_cast<uint32_t>(BlockExecWeight::UNWIND);
 
   // Check if the block contains 'cold' call.
   for (const auto &I : *BB)