From: Nirav Dave <niravd@google.com>
Date: Thu, 2 Feb 2017 14:39:26 +0000 (+0000)
Subject: [X86,ISEL] Fix X86 increment chain dependence calculation
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=a25e135627ee6e4cbd7bd73b00b2e184d9f243ea;p=llvm

[X86,ISEL] Fix X86 increment chain dependence calculation

Merging Load-add-store pattern into a increment op previously dropped
the load's chain from the instructions dependence if the store is
chained to a TokenFactor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293892 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index 8ab4c061688..7f08d2dea9d 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -1905,6 +1905,8 @@ static bool isLoadIncOrDecStore(StoreSDNode *StoreNode, unsigned Opc,
       SDValue Op = Chain.getOperand(i);
       if (Op == Load.getValue(1)) {
         ChainCheck = true;
+        // Drop Load, but keep its chain. No cycle check necessary.
+        ChainOps.push_back(Load.getOperand(0));
         continue;
       }