[X86][SSE] Prefer to combine shuffles to VZEXT over VZEXT_MOVL.

This matches what is already done during shuffle lowering and helps prevent the need for a zero-vector in cases where shuffles match both patterns.

llvm-svn: 295723

1 files changed, 9 insertions, 9 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 8a9a8fa06bf..3aecdc269b5 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -26387,15 +26387,6 @@ static bool matchUnaryVectorShuffle(MVT MaskVT, ArrayRef<int> Mask,
   unsigned NumMaskElts = Mask.size();
   unsigned MaskEltSize = MaskVT.getScalarSizeInBits();
 
-  // Match against a VZEXT_MOVL instruction, SSE1 only supports 32-bits (MOVSS).
-  if (((MaskEltSize == 32) || (MaskEltSize == 64 && Subtarget.hasSSE2())) &&
-      isUndefOrEqual(Mask[0], 0) &&
-      isUndefOrZeroInRange(Mask, 1, NumMaskElts - 1)) {
-    Shuffle = X86ISD::VZEXT_MOVL;
-    SrcVT = DstVT = !Subtarget.hasSSE2() ? MVT::v4f32 : MaskVT;
-    return true;
-  }
-
   // Match against a VZEXT instruction.
   // TODO: Add 512-bit vector support (split AVX512F and AVX512BW).
   if (AllowIntDomain && ((MaskVT.is128BitVector() && Subtarget.hasSSE41()) ||
@@ -26421,6 +26412,15 @@ static bool matchUnaryVectorShuffle(MVT MaskVT, ArrayRef<int> Mask,
     }
   }
 
+  // Match against a VZEXT_MOVL instruction, SSE1 only supports 32-bits (MOVSS).
+  if (((MaskEltSize == 32) || (MaskEltSize == 64 && Subtarget.hasSSE2())) &&
+      isUndefOrEqual(Mask[0], 0) &&
+      isUndefOrZeroInRange(Mask, 1, NumMaskElts - 1)) {
+    Shuffle = X86ISD::VZEXT_MOVL;
+    SrcVT = DstVT = !Subtarget.hasSSE2() ? MVT::v4f32 : MaskVT;
+    return true;
+  }
+
   // Check if we have SSE3 which will let us use MOVDDUP etc. The
   // instructions are no slower than UNPCKLPD but has the option to
   // fold the input operand into even an unaligned memory load.