[X86][SSE] Generalised combining to VZEXT_MOVL to any vector size

This doesn't change tests codegen as we already combined to blend+zero which is what we lower VZEXT_MOVL to on SSE41+ targets, but it does put us in a better position when we improve shuffling for optsize.

llvm-svn: 279273

1 files changed, 8 insertions, 6 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 7745e6c4ce9..84dade757fc 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -24906,14 +24906,17 @@ static SDValue combineShuffle256(SDNode *N, SelectionDAG &DAG,
 static bool matchUnaryVectorShuffle(MVT MaskVT, ArrayRef<int> Mask,
                                     const X86Subtarget &Subtarget,
                                     unsigned &Shuffle, MVT &ShuffleVT) {
+  unsigned NumMaskElts = Mask.size();
   bool FloatDomain = MaskVT.isFloatingPoint() ||
                      (!Subtarget.hasAVX2() && MaskVT.is256BitVector());
 
-  // Match a 128-bit vector against a VZEXT_MOVL instruction.
-  if (MaskVT.is128BitVector() && Subtarget.hasSSE2() &&
-      isTargetShuffleEquivalent(Mask, {0, SM_SentinelZero})) {
+  // Match against a VZEXT_MOVL instruction, SSE1 only supports 32-bits (MOVSS).
+  if (((MaskVT.getScalarSizeInBits() == 32) ||
+       (MaskVT.getScalarSizeInBits() == 64 && Subtarget.hasSSE2())) &&
+      isUndefOrEqual(Mask[0], 0) &&
+      isUndefOrZeroInRange(Mask, 1, NumMaskElts - 1)) {
     Shuffle = X86ISD::VZEXT_MOVL;
-    ShuffleVT = MaskVT;
+    ShuffleVT = !Subtarget.hasSSE2() ? MVT::v4f32 : MaskVT;
     return true;
   }
 
@@ -24981,8 +24984,7 @@ static bool matchUnaryVectorShuffle(MVT MaskVT, ArrayRef<int> Mask,
 
   // Attempt to match against broadcast-from-vector.
   if (Subtarget.hasAVX2()) {
-    unsigned NumElts = Mask.size();
-    SmallVector<int, 64> BroadcastMask(NumElts, 0);
+    SmallVector<int, 64> BroadcastMask(NumMaskElts, 0);
     if (isTargetShuffleEquivalent(Mask, BroadcastMask)) {
       ShuffleVT = MaskVT;
       Shuffle = X86ISD::VBROADCAST;