3 files changed, 24 insertions, 1 deletions
diff --git a/include/llvm/Target/TargetLowering.h b/include/llvm/Target/TargetLowering.h
index 57e142139b..e6917b74e7 100644
--- a/include/llvm/Target/TargetLowering.h
+++ b/include/llvm/Target/TargetLowering.h
@@ -173,6 +173,11 @@ public:
     return true;
   }
 
+  /// Return true if multiple condition registers are available.
+  bool hasMultipleConditionRegisters() const {
+    return HasMultipleConditionRegisters;
+  }
+
   /// Return true if a vector of the given type should be split
   /// (TypeSplitVector) instead of promoted (TypePromoteInteger) during type
   /// legalization.
@@ -926,6 +931,15 @@ protected:
     SelectIsExpensive = isExpensive;
   }
 
+  /// Tells the code generator that the target has multiple (allocatable)
+  /// condition registers that can be used to store the results of comparisons
+  /// for use by selects and conditional branches. With multiple condition
+  /// registers, the code generator will not aggressively sink comparisons into
+  /// the blocks of their users.
+  void setHasMultipleConditionRegisters(bool hasManyRegs = true) {
+    HasMultipleConditionRegisters = hasManyRegs;
+  }
+
   /// Tells the code generator not to expand sequence of operations into a
   /// separate sequences that increases the amount of flow control.
   void setJumpIsExpensive(bool isExpensive = true) {
@@ -1321,6 +1335,13 @@ private:
   /// the select operations if possible.
   bool SelectIsExpensive;
 
+  /// Tells the code generator that the target has multiple (allocatable)
+  /// condition registers that can be used to store the results of comparisons
+  /// for use by selects and conditional branches. With multiple condition
+  /// registers, the code generator will not aggressively sink comparisons into
+  /// the blocks of their users.
+  bool HasMultipleConditionRegisters;
+
   /// Tells the code generator not to expand integer divides by constants into a
   /// sequence of muls, adds, and shifts.  This is a hack until a real cost
   /// model is in place.  If we ever optimize for size, this will be set to true
diff --git a/lib/CodeGen/TargetLoweringBase.cpp b/lib/CodeGen/TargetLoweringBase.cpp
index 7b1931d407..beaa9b9f74 100644
--- a/lib/CodeGen/TargetLoweringBase.cpp
+++ b/lib/CodeGen/TargetLoweringBase.cpp
@@ -672,6 +672,7 @@ TargetLoweringBase::TargetLoweringBase(const TargetMachine &tm,
   UseUnderscoreSetJmp = false;
   UseUnderscoreLongJmp = false;
   SelectIsExpensive = false;
+  HasMultipleConditionRegisters = false;
   IntDivIsCheap = false;
   Pow2DivIsCheap = false;
   JumpIsExpensive = false;
diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp
index 007e9b79e2..79d92ce5a5 100644
--- a/lib/Transforms/Scalar/CodeGenPrepare.cpp
+++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp
@@ -1916,7 +1916,8 @@ bool CodeGenPrepare::OptimizeInst(Instruction *I) {
   }
 
   if (CmpInst *CI = dyn_cast<CmpInst>(I))
-    return OptimizeCmpExpression(CI);
+    if (!TLI || !TLI->hasMultipleConditionRegisters())
+      return OptimizeCmpExpression(CI);
 
   if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
     if (TLI)