[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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302612 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp
index 75359fe3c0ea695de0424e976a83065af87b858c..7392c832714879706db51beef28cb905c81ba392 100644 (file)
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/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;

diff --git a/test/CodeGen/X86/O0-pipeline.ll b/test/CodeGen/X86/O0-pipeline.ll
index 0002dbe5c945287981e02690c5dab67daae43327..12e13f2a4ffa11b671618a828094d8a1a50e8985 100644 (file)
--- a/test/CodeGen/X86/O0-pipeline.ll
+++ b/test/CodeGen/X86/O0-pipeline.ll
@@ -36,9 +36,6 @@
 ; CHECK-NEXT:       Local Stack Slot Allocation
 ; CHECK-NEXT:       X86 WinAlloca Expander
 ; CHECK-NEXT:       Eliminate PHI nodes for register allocation
-; CHECK-NEXT:       Dominator Tree Construction
-; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:       Function Alias Analysis Results
 ; CHECK-NEXT:       Two-Address instruction pass
 ; CHECK-NEXT:       Fast Register Allocator
 ; CHECK-NEXT:       Bundle Machine CFG Edges