[llvm] 6b5198f - [X86] Simplify broadcast mask detection with isUndefOrEqual helper.

[Simon Pilgrim via llvm-commits]

Author: Simon Pilgrim
Date: 2020-09-28T12:53:56+01:00
New Revision: 6b5198f06b585e1fa3be530be2fbc76dd2d442c1

URL: https://github.com/llvm/llvm-project/commit/6b5198f06b585e1fa3be530be2fbc76dd2d442c1
DIFF: https://github.com/llvm/llvm-project/commit/6b5198f06b585e1fa3be530be2fbc76dd2d442c1.diff

LOG: [X86] Simplify broadcast mask detection with isUndefOrEqual helper.

Add an additional isUndefOrEqual variant that matches an entire mask, not just a single value.

Added: 
    

Modified: 
    llvm/lib/Target/X86/X86ISelLowering.cpp

Removed: 
    


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diff  --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 0388cb72a76c..b079ee4c2e0d 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -5414,6 +5414,14 @@ static bool isUndefOrEqual(int Val, int CmpVal) {
   return ((Val == SM_SentinelUndef) || (Val == CmpVal));
 }
 
+/// Return true if every element in Mask is the undef sentinel value or equal to
+/// the specified value..
+static bool isUndefOrEqual(ArrayRef<int> Mask, int CmpVal) {
+  return llvm::all_of(Mask, [CmpVal](int M) {
+    return (M == SM_SentinelUndef) || (M == CmpVal);
+  });
+}
+
 /// Val is either the undef or zero sentinel value.
 static bool isUndefOrZero(int Val) {
   return ((Val == SM_SentinelUndef) || (Val == SM_SentinelZero));
@@ -34932,8 +34940,7 @@ static SDValue combineX86ShuffleChain(ArrayRef<SDValue> Inputs, SDValue Root,
   // shuffle(insert_subvector(undef, sub, 0), undef, 0, 0, 0, 0)
   if (UnaryShuffle &&
       (BaseMaskEltSizeInBits == 128 || BaseMaskEltSizeInBits == 256)) {
-    SmallVector<int, 64> BroadcastMask(NumBaseMaskElts, 0);
-    if (isTargetShuffleEquivalent(BaseMask, BroadcastMask)) {
+    if (isUndefOrEqual(BaseMask, 0)) {
       SDValue Src = Inputs[0];
       if (Src.getOpcode() == ISD::INSERT_SUBVECTOR &&
           Src.getOperand(0).isUndef() &&
@@ -35139,8 +35146,7 @@ static SDValue combineX86ShuffleChain(ArrayRef<SDValue> Inputs, SDValue Root,
     if ((Subtarget.hasAVX2() ||
          (Subtarget.hasAVX() && 32 <= MaskEltSizeInBits)) &&
         (!IsMaskedShuffle || NumRootElts == NumMaskElts)) {
-      SmallVector<int, 64> BroadcastMask(NumMaskElts, 0);
-      if (isTargetShuffleEquivalent(Mask, BroadcastMask)) {
+      if (isUndefOrEqual(Mask, 0)) {
         if (V1.getValueType() == MaskVT &&
             V1.getOpcode() == ISD::SCALAR_TO_VECTOR &&
             MayFoldLoad(V1.getOperand(0))) {