From: Dan Gohman <gohman@apple.com>
Date: Wed, 28 Oct 2009 15:28:02 +0000 (+0000)
Subject: Don't call SDNode::isPredecessorOf when it isn't necessary. If the load's
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=1507cd03a64679f6999f51218a3a0180d51ab673;p=oota-llvm.git

Don't call SDNode::isPredecessorOf when it isn't necessary. If the load's
chains have no users, they can't be predecessors of the condition.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85394 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index b379515480b..ef1ab2728cd 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -5737,8 +5737,10 @@ bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDValue LHS,
         if (TheSelect->getOpcode() == ISD::SELECT) {
           // Check that the condition doesn't reach either load.  If so, folding
           // this will induce a cycle into the DAG.
-          if (!LLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) &&
-              !RLD->isPredecessorOf(TheSelect->getOperand(0).getNode())) {
+          if ((!LLD->hasAnyUseOfValue(1) ||
+               !LLD->isPredecessorOf(TheSelect->getOperand(0).getNode())) &&
+              (!RLD->hasAnyUseOfValue(1) ||
+               !RLD->isPredecessorOf(TheSelect->getOperand(0).getNode()))) {
             Addr = DAG.getNode(ISD::SELECT, TheSelect->getDebugLoc(),
                                LLD->getBasePtr().getValueType(),
                                TheSelect->getOperand(0), LLD->getBasePtr(),
@@ -5747,10 +5749,12 @@ bool DAGCombiner::SimplifySelectOps(SDNode *TheSelect, SDValue LHS,
         } else {
           // Check that the condition doesn't reach either load.  If so, folding
           // this will induce a cycle into the DAG.
-          if (!LLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) &&
-              !RLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) &&
-              !LLD->isPredecessorOf(TheSelect->getOperand(1).getNode()) &&
-              !RLD->isPredecessorOf(TheSelect->getOperand(1).getNode())) {
+          if ((!LLD->hasAnyUseOfValue(1) ||
+               (!LLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) &&
+                !LLD->isPredecessorOf(TheSelect->getOperand(1).getNode()))) &&
+              (!RLD->hasAnyUseOfValue(1) ||
+               (!RLD->isPredecessorOf(TheSelect->getOperand(0).getNode()) &&
+                !RLD->isPredecessorOf(TheSelect->getOperand(1).getNode())))) {
             Addr = DAG.getNode(ISD::SELECT_CC, TheSelect->getDebugLoc(),
                                LLD->getBasePtr().getValueType(),
                                TheSelect->getOperand(0),