From 0997ba3d13be00326b8001a74bc55bed6805a756 Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Fri, 11 Mar 2016 13:53:18 +0000
Subject: [PATCH] [AA] Make BasicAA just require domtree.

This doesn't change how many times we construct domtrees in the normal
pipeline, and it removes fragility and instability where basic-aa may
not be run in time to see domtrees because they happen to be constructed
afterward.

This isn't quite as clean as the change to memdep because there is
a mode where basic-aa specifically runs without domtrees -- in the
hacking version used by function-attrs with the legacy pass manager.

llvm-svn: 263234
---
 lib/Analysis/BasicAliasAnalysis.cpp | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index 18972105b88..d8f6f109815 100644
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -1612,7 +1612,7 @@ BasicAAResult BasicAA::run(Function &F, AnalysisManager<Function> &AM) {
   return BasicAAResult(F.getParent()->getDataLayout(),
                        AM.getResult<TargetLibraryAnalysis>(F),
                        AM.getResult<AssumptionAnalysis>(F),
-                       AM.getCachedResult<DominatorTreeAnalysis>(F),
+                       &AM.getResult<DominatorTreeAnalysis>(F),
                        AM.getCachedResult<LoopAnalysis>(F));
 }
 
@@ -1626,6 +1626,7 @@ void BasicAAWrapperPass::anchor() {}
 INITIALIZE_PASS_BEGIN(BasicAAWrapperPass, "basicaa",
                       "Basic Alias Analysis (stateless AA impl)", true, true)
 INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
 INITIALIZE_PASS_END(BasicAAWrapperPass, "basicaa",
                     "Basic Alias Analysis (stateless AA impl)", true, true)
@@ -1637,12 +1638,11 @@ FunctionPass *llvm::createBasicAAWrapperPass() {
 bool BasicAAWrapperPass::runOnFunction(Function &F) {
   auto &ACT = getAnalysis<AssumptionCacheTracker>();
   auto &TLIWP = getAnalysis<TargetLibraryInfoWrapperPass>();
-  auto *DTWP = getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+  auto &DTWP = getAnalysis<DominatorTreeWrapperPass>();
   auto *LIWP = getAnalysisIfAvailable<LoopInfoWrapperPass>();
 
   Result.reset(new BasicAAResult(F.getParent()->getDataLayout(), TLIWP.getTLI(),
-                                 ACT.getAssumptionCache(F),
-                                 DTWP ? &DTWP->getDomTree() : nullptr,
+                                 ACT.getAssumptionCache(F), &DTWP.getDomTree(),
                                  LIWP ? &LIWP->getLoopInfo() : nullptr));
 
   return false;
@@ -1651,6 +1651,7 @@ bool BasicAAWrapperPass::runOnFunction(Function &F) {
 void BasicAAWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesAll();
   AU.addRequired<AssumptionCacheTracker>();
+  AU.addRequired<DominatorTreeWrapperPass>();
   AU.addRequired<TargetLibraryInfoWrapperPass>();
 }