1 files changed, 21 insertions, 12 deletions
diff --git a/lib/CodeGen/BasicTargetTransformInfo.cpp b/lib/CodeGen/BasicTargetTransformInfo.cpp
index 3892cc4..59192f4 100644
--- a/lib/CodeGen/BasicTargetTransformInfo.cpp
+++ b/lib/CodeGen/BasicTargetTransformInfo.cpp
@@ -241,6 +241,27 @@ unsigned BasicTTI::getCastInstrCost(unsigned Opcode, Type *Dst,
   std::pair<unsigned, MVT> SrcLT = TLI->getTypeLegalizationCost(Src);
   std::pair<unsigned, MVT> DstLT = TLI->getTypeLegalizationCost(Dst);
 
+  // Check for NOOP conversions.
+  if (SrcLT.first == DstLT.first &&
+      SrcLT.second.getSizeInBits() == DstLT.second.getSizeInBits()) {
+
+      // Bitcast between types that are legalized to the same type are free.
+      if (Opcode == Instruction::BitCast || Opcode == Instruction::Trunc)
+        return 0;
+  }
+
+  if (Opcode == Instruction::Trunc &&
+      TLI->isTruncateFree(SrcLT.second, DstLT.second))
+    return 0;
+
+  if (Opcode == Instruction::ZExt &&
+      TLI->isZExtFree(SrcLT.second, DstLT.second))
+    return 0;
+
+  // If the cast is marked as legal (or promote) then assume low cost.
+  if (TLI->isOperationLegalOrPromote(ISD, DstLT.second))
+    return 1;
+
   // Handle scalar conversions.
   if (!Src->isVectorTy() && !Dst->isVectorTy()) {
 
@@ -248,14 +269,6 @@ unsigned BasicTTI::getCastInstrCost(unsigned Opcode, Type *Dst,
     if (Opcode == Instruction::BitCast)
       return 0;
 
-    if (Opcode == Instruction::Trunc &&
-        TLI->isTruncateFree(SrcLT.second, DstLT.second))
-      return 0;
-
-    if (Opcode == Instruction::ZExt &&
-        TLI->isZExtFree(SrcLT.second, DstLT.second))
-      return 0;
-
     // Just check the op cost. If the operation is legal then assume it costs 1.
     if (!TLI->isOperationExpand(ISD, DstLT.second))
       return  1;
@@ -271,10 +284,6 @@ unsigned BasicTTI::getCastInstrCost(unsigned Opcode, Type *Dst,
     if (SrcLT.first == DstLT.first &&
         SrcLT.second.getSizeInBits() == DstLT.second.getSizeInBits()) {
 
-      // Bitcast between types that are legalized to the same type are free.
-      if (Opcode == Instruction::BitCast || Opcode == Instruction::Trunc)
-        return 0;
-
       // Assume that Zext is done using AND.
       if (Opcode == Instruction::ZExt)
         return 1;