2 files changed, 27 insertions, 7 deletions
diff --git a/lib/Target/ARM/ARMISelLowering.h b/lib/Target/ARM/ARMISelLowering.h
index 13b83de85d..757c68ee37 100644
--- a/lib/Target/ARM/ARMISelLowering.h
+++ b/lib/Target/ARM/ARMISelLowering.h
@@ -257,6 +257,11 @@ namespace llvm {
 
     virtual const char *getTargetNodeName(unsigned Opcode) const;
 
+    virtual bool isSelectSupported(SelectSupportKind Kind) const {
+      // ARM does not support scalar condition selects on vectors.
+      return (Kind != ScalarCondVectorVal);
+    }
+
     /// getSetCCResultType - Return the value type to use for ISD::SETCC.
     virtual EVT getSetCCResultType(EVT VT) const;
 
diff --git a/lib/Transforms/Scalar/CodeGenPrepare.cpp b/lib/Transforms/Scalar/CodeGenPrepare.cpp
index cfca726f26..57a648f7b9 100644
--- a/lib/Transforms/Scalar/CodeGenPrepare.cpp
+++ b/lib/Transforms/Scalar/CodeGenPrepare.cpp
@@ -1174,17 +1174,32 @@ static bool isFormingBranchFromSelectProfitable(SelectInst *SI) {
 }
 
 
+/// If we have a SelectInst that will likely profit from branch prediction,
+/// turn it into a branch.
 bool CodeGenPrepare::OptimizeSelectInst(SelectInst *SI) {
-  // If we have a SelectInst that will likely profit from branch prediction,
-  // turn it into a branch.
-  if (DisableSelectToBranch || OptSize || !TLI ||
-      !TLI->isPredictableSelectExpensive())
-    return false;
+  bool VectorCond = !SI->getCondition()->getType()->isIntegerTy(1);
 
-  if (!SI->getCondition()->getType()->isIntegerTy(1) ||
-      !isFormingBranchFromSelectProfitable(SI))
+  // Can we convert the 'select' to CF ?
+  if (DisableSelectToBranch || OptSize || !TLI || VectorCond)
     return false;
 
+  TargetLowering::SelectSupportKind SelectKind;
+  if (VectorCond)
+    SelectKind = TargetLowering::VectorMaskSelect;
+  else if (SI->getType()->isVectorTy())
+    SelectKind = TargetLowering::ScalarCondVectorVal;
+  else
+    SelectKind = TargetLowering::ScalarValSelect;
+
+  // Do we have efficient codegen support for this kind of 'selects' ?
+  if (TLI->isSelectSupported(SelectKind)) {
+    // We have efficient codegen support for the select instruction.
+    // Check if it is profitable to keep this 'select'.
+    if (!TLI->isPredictableSelectExpensive() ||
+        !isFormingBranchFromSelectProfitable(SI))
+      return false;
+  }
+
   ModifiedDT = true;
 
   // First, we split the block containing the select into 2 blocks.