Const-correct and prevent a copy of a SmallPtrSet.

[oota-llvm.git] / lib / Transforms / Utils / FlattenCFG.cpp

diff --git a/lib/Transforms/Utils/FlattenCFG.cpp b/lib/Transforms/Utils/FlattenCFG.cpp
index ffdfacdc59f21efb442bbd73d514c81759bfb016..4eb3e3dd17d28540e1f2abc51a4b69d5b7cf3be5 100644 (file)
--- a/lib/Transforms/Utils/FlattenCFG.cpp
+++ b/lib/Transforms/Utils/FlattenCFG.cpp
@@ -28,11 +28,12 @@ class FlattenCFGOpt {
   AliasAnalysis *AA;
   /// \brief Use parallel-and or parallel-or to generate conditions for
   /// conditional branches.
-  bool FlattenParallelAndOr(BasicBlock *BB, IRBuilder<> &Builder, Pass *P = 0);
+  bool FlattenParallelAndOr(BasicBlock *BB, IRBuilder<> &Builder,
+                            Pass *P = nullptr);
   /// \brief If \param BB is the merge block of an if-region, attempt to merge
   /// the if-region with an adjacent if-region upstream if two if-regions
   /// contain identical instructions.
-  bool MergeIfRegion(BasicBlock *BB, IRBuilder<> &Builder, Pass *P = 0);
+  bool MergeIfRegion(BasicBlock *BB, IRBuilder<> &Builder, Pass *P = nullptr);
   /// \brief Compare a pair of blocks: \p Block1 and \p Block2, which
   /// are from two if-regions whose entry blocks are \p Head1 and \p
   /// Head2.  \returns true if \p Block1 and \p Block2 contain identical
@@ -127,9 +128,9 @@ bool FlattenCFGOpt::FlattenParallelAndOr(BasicBlock *BB, IRBuilder<> &Builder,
   if (PHI)
     return false; // For simplicity, avoid cases containing PHI nodes.
 
-  BasicBlock *LastCondBlock = NULL;
-  BasicBlock *FirstCondBlock = NULL;
-  BasicBlock *UnCondBlock = NULL;
+  BasicBlock *LastCondBlock = nullptr;
+  BasicBlock *FirstCondBlock = nullptr;
+  BasicBlock *UnCondBlock = nullptr;
   int Idx = -1;
 
   // Check predecessors of \param BB.
@@ -237,9 +238,13 @@ bool FlattenCFGOpt::FlattenParallelAndOr(BasicBlock *BB, IRBuilder<> &Builder,
     // Do branch inversion.
     BasicBlock *CurrBlock = LastCondBlock;
     bool EverChanged = false;
-    while (1) {
+    for (;CurrBlock != FirstCondBlock;
+          CurrBlock = CurrBlock->getSinglePredecessor()) {
       BranchInst *BI = dyn_cast<BranchInst>(CurrBlock->getTerminator());
       CmpInst *CI = dyn_cast<CmpInst>(BI->getCondition());
+      if (!CI)
+        continue;
+
       CmpInst::Predicate Predicate = CI->getPredicate();
       // Canonicalize icmp_ne -> icmp_eq, fcmp_one -> fcmp_oeq
       if ((Predicate == CmpInst::ICMP_NE) || (Predicate == CmpInst::FCMP_ONE)) {
@@ -247,9 +252,6 @@ bool FlattenCFGOpt::FlattenParallelAndOr(BasicBlock *BB, IRBuilder<> &Builder,
         BI->swapSuccessors();
         EverChanged = true;
       }
-      if (CurrBlock == FirstCondBlock)
-        break;
-      CurrBlock = CurrBlock->getSinglePredecessor();
     }
     return EverChanged;
   }