From f030d6b014bf60d56d71d4502a3b6973f76efe30 Mon Sep 17 00:00:00 2001
From: Xin Tong <trent.xin.tong@gmail.com>
Date: Mon, 20 Mar 2017 00:30:19 +0000
Subject: [PATCH] Remove unnecessary IDom check
Summary: This Idom check seems unnecessary. The immediate children of a node on the Dominator Tree should always be the IDom of its immediate children in this case.
Reviewers: hfinkel, majnemer, dberlin
Reviewed By: dberlin
Subscribers: dberlin, davide, llvm-commits
Differential Revision: https://reviews.llvm.org/D26954
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@298232 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/Transforms/Scalar/Sink.cpp | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/lib/Transforms/Scalar/Sink.cpp b/lib/Transforms/Scalar/Sink.cpp
index 504a22a229c..102e9eaeab7 100644
--- a/lib/Transforms/Scalar/Sink.cpp
+++ b/lib/Transforms/Scalar/Sink.cpp
@@ -164,13 +164,14 @@ static bool SinkInstruction(Instruction *Inst,
// Instructions can only be sunk if all their uses are in blocks
// dominated by one of the successors.
- // Look at all the postdominators and see if we can sink it in one.
+ // Look at all the dominated blocks and see if we can sink it in one.
DomTreeNode *DTN = DT.getNode(Inst->getParent());
for (DomTreeNode::iterator I = DTN->begin(), E = DTN->end();
I != E && SuccToSinkTo == nullptr; ++I) {
BasicBlock *Candidate = (*I)->getBlock();
- if ((*I)->getIDom()->getBlock() == Inst->getParent() &&
- IsAcceptableTarget(Inst, Candidate, DT, LI))
+ // A node always immediate-dominates its children on the dominator
+ // tree.
+ if (IsAcceptableTarget(Inst, Candidate, DT, LI))
SuccToSinkTo = Candidate;
}
--
2.40.0