From a09ff59cc2f9c94432fb29dfbfcda095ef3bc5e8 Mon Sep 17 00:00:00 2001
From: Ahmed Bougacha <ahmed.bougacha@gmail.com>
Date: Wed, 10 May 2017 00:56:00 +0000
Subject: [CodeGen] Don't require AA in TwoAddress at -O0.

This is a follow-up to r302611, which moved an -O0 computation of DT
from SDAGISel to TwoAddress.

Don't use it here either, and avoid computing it completely.  The only
use was forwarding the analysis as an optional argument to utility
functions.

Differential Revision: https://reviews.llvm.org/D32766

llvm-svn: 302612
---
 llvm/lib/CodeGen/TwoAddressInstructionPass.cpp | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

(limited to 'llvm/lib/CodeGen/TwoAddressInstructionPass.cpp')

diff --git a/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp b/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
index 75359fe3c0e..7392c832714 100644
--- a/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/llvm/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -155,7 +155,7 @@ public:
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.setPreservesCFG();
-    AU.addRequired<AAResultsWrapperPass>();
+    AU.addUsedIfAvailable<AAResultsWrapperPass>();
     AU.addUsedIfAvailable<LiveVariables>();
     AU.addPreserved<LiveVariables>();
     AU.addPreserved<SlotIndexes>();
@@ -1627,7 +1627,10 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &Func) {
   InstrItins = MF->getSubtarget().getInstrItineraryData();
   LV = getAnalysisIfAvailable<LiveVariables>();
   LIS = getAnalysisIfAvailable<LiveIntervals>();
-  AA = &getAnalysis<AAResultsWrapperPass>().getAAResults();
+  if (auto *AAPass = getAnalysisIfAvailable<AAResultsWrapperPass>())
+    AA = &AAPass->getAAResults();
+  else
+    AA = nullptr;
   OptLevel = TM.getOptLevel();
 
   bool MadeChange = false;
-- 
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