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

2 files changed, 19 insertions, 0 deletions

diff --git a/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h b/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h
index 3645a5b12fd..0ab3b3f4a5e 100644
--- a/llvm/include/llvm/Analysis/ScalarEvolutionExpressions.h
+++ b/llvm/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/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 82be9cd5c4e..12be58e8b3a 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/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)