From 1e93b1c02209036dd97cd3ac418adcf6ad0da219 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Sat, 13 Feb 2010 00:19:39 +0000
Subject: [PATCH] Override dominates and properlyDominates for SCEVAddRecExpr,
 as a SCEVAddRecExpr doesn't necessarily dominate blocks merely dominated by
 all of its operands. This fixes an abort compiling 403.gcc.

llvm-svn: 96056
---
 .../llvm/Analysis/ScalarEvolutionExpressions.h    |  4 ++++
 lib/Analysis/ScalarEvolution.cpp                  | 15 +++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/include/llvm/Analysis/ScalarEvolutionExpressions.h b/include/llvm/Analysis/ScalarEvolutionExpressions.h
index 3645a5b12fd..0ab3b3f4a5e 100644
--- a/include/llvm/Analysis/ScalarEvolutionExpressions.h
+++ b/include/llvm/Analysis/ScalarEvolutionExpressions.h
@@ -417,6 +417,10 @@ namespace llvm {
 
     virtual bool isLoopInvariant(const Loop *QueryLoop) const;
 
+    bool dominates(BasicBlock *BB, DominatorTree *DT) const;
+
+    bool properlyDominates(BasicBlock *BB, DominatorTree *DT) const;
+
     /// isAffine - Return true if this is an affine AddRec (i.e., it represents
     /// an expressions A+B*x where A and B are loop invariant values.
     bool isAffine() const {
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 82be9cd5c4e..12be58e8b3a 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -312,6 +312,21 @@ bool SCEVAddRecExpr::isLoopInvariant(const Loop *QueryLoop) const {
   return true;
 }
 
+bool
+SCEVAddRecExpr::dominates(BasicBlock *BB, DominatorTree *DT) const {
+  return DT->dominates(L->getHeader(), BB) &&
+         SCEVNAryExpr::dominates(BB, DT);
+}
+
+bool
+SCEVAddRecExpr::properlyDominates(BasicBlock *BB, DominatorTree *DT) const {
+  // This uses a "dominates" query instead of "properly dominates" query because
+  // the instruction which produces the addrec's value is a PHI, and a PHI
+  // effectively properly dominates its entire containing block.
+  return DT->dominates(L->getHeader(), BB) &&
+         SCEVNAryExpr::properlyDominates(BB, DT);
+}
+
 void SCEVAddRecExpr::print(raw_ostream &OS) const {
   OS << "{" << *Operands[0];
   for (unsigned i = 1, e = Operands.size(); i != e; ++i)