[Hexagon] Prefer to widen HVX vectors instead of promoting

llvm-svn: 321002

2 files changed, 14 insertions, 0 deletions

diff --git a/llvm/lib/Target/Hexagon/HexagonISelLowering.cpp b/llvm/lib/Target/Hexagon/HexagonISelLowering.cpp
index 6ae52701f7f..6387ac2ef67 100644
--- a/llvm/lib/Target/Hexagon/HexagonISelLowering.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonISelLowering.cpp
@@ -2323,6 +2323,18 @@ bool HexagonTargetLowering::isShuffleMaskLegal(ArrayRef<int> Mask,
   return true;
 }
 
+TargetLoweringBase::LegalizeTypeAction
+HexagonTargetLowering::getPreferredVectorAction(EVT VT) const {
+  if (Subtarget.useHVXOps()) {
+    // If the size of VT is at least half of the vector length,
+    // widen the vector. Note: the threshold was not selected in
+    // any scientific way.
+    if (VT.getSizeInBits() >= Subtarget.getVectorLength()*8/2)
+      return TargetLoweringBase::TypeWidenVector;
+  }
+  return TargetLowering::getPreferredVectorAction(VT);
+}
+
 // Lower a vector shuffle (V1, V2, V3).  V1 and V2 are the two vectors
 // to select data from, V3 is the permutation.
 SDValue
diff --git a/llvm/lib/Target/Hexagon/HexagonISelLowering.h b/llvm/lib/Target/Hexagon/HexagonISelLowering.h
index 07f8b0c9c14..2705fcbf8d6 100644
--- a/llvm/lib/Target/Hexagon/HexagonISelLowering.h
+++ b/llvm/lib/Target/Hexagon/HexagonISelLowering.h
@@ -122,6 +122,8 @@ namespace HexagonISD {
         unsigned DefinedValues) const override;
 
     bool isShuffleMaskLegal(ArrayRef<int> Mask, EVT VT) const override;
+    TargetLoweringBase::LegalizeTypeAction getPreferredVectorAction(EVT VT)
+        const override;
 
     SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const override;
     const char *getTargetNodeName(unsigned Opcode) const override;