From: Jun Bum Lim <junbuml@codeaurora.org>
Date: Wed, 1 Feb 2017 19:06:55 +0000 (+0000)
Subject: [JumpThread] No need to erase BB from LoopHeaders. NFC.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d44f51cf08f005c12d601035283501fb2559a3c1;p=llvm

[JumpThread] No need to erase BB from LoopHeaders. NFC.

Summary: No need to try to ease BB from LoopHeaders as we already know that BB is not in LoopHeaders.

Reviewers: hsung, majnemer, mcrosier, haicheng, rengolin

Reviewed By: rengolin

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D29232

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293802 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index ecc6a0afbad..e8e40330665 100644
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -222,26 +222,13 @@ bool JumpThreadingPass::runImpl(Function &F, TargetLibraryInfo *TLI_,
           BB != &BB->getParent()->getEntryBlock() &&
           // If the terminator is the only non-phi instruction, try to nuke it.
           BB->getFirstNonPHIOrDbg()->isTerminator() && !LoopHeaders.count(BB)) {
-        // Since TryToSimplifyUncondBranchFromEmptyBlock may delete the
-        // block, we have to make sure it isn't in the LoopHeaders set.  We
-        // reinsert afterward if needed.
-        bool ErasedFromLoopHeaders = LoopHeaders.erase(BB);
-        BasicBlock *Succ = BI->getSuccessor(0);
-
         // FIXME: It is always conservatively correct to drop the info
         // for a block even if it doesn't get erased.  This isn't totally
         // awesome, but it allows us to use AssertingVH to prevent nasty
         // dangling pointer issues within LazyValueInfo.
         LVI->eraseBlock(BB);
-        if (TryToSimplifyUncondBranchFromEmptyBlock(BB)) {
+        if (TryToSimplifyUncondBranchFromEmptyBlock(BB))
           Changed = true;
-          // If we deleted BB and BB was the header of a loop, then the
-          // successor is now the header of the loop.
-          BB = Succ;
-        }
-
-        if (ErasedFromLoopHeaders)
-          LoopHeaders.insert(BB);
       }
     }
     EverChanged |= Changed;