[X86] Add growShuffleMask helper to grow the shuffle mask for a larger value type. NFC. (#134243)
Prep work for #133947
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 8271d9c..d1be195 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -3941,6 +3941,24 @@
return scaleShuffleElements(Mask, NumDstElts, ScaledMask);
}
+// Helper to grow the shuffle mask for a larger value type.
+// NOTE: This is different to scaleShuffleElements which is a same size type.
+static void growShuffleMask(ArrayRef<int> SrcMask,
+ SmallVectorImpl<int> &DstMask,
+ unsigned SrcSizeInBits, unsigned DstSizeInBits) {
+ assert(DstMask.empty() && "Expected an empty shuffle mas");
+ assert((DstSizeInBits % SrcSizeInBits) == 0 && "Illegal shuffle scale");
+ unsigned Scale = DstSizeInBits / SrcSizeInBits;
+ unsigned NumSrcElts = SrcMask.size();
+ DstMask.assign(SrcMask.begin(), SrcMask.end());
+ for (int &M : DstMask) {
+ if (M < 0)
+ continue;
+ M = (M % NumSrcElts) + ((M / NumSrcElts) * Scale * NumSrcElts);
+ }
+ DstMask.append((Scale - 1) * NumSrcElts, SM_SentinelUndef);
+}
+
/// Returns true if Elt is a constant zero or a floating point constant +0.0.
bool X86::isZeroNode(SDValue Elt) {
return isNullConstant(Elt) || isNullFPConstant(Elt);
@@ -40456,19 +40474,13 @@
}
// Bail if we fail to find a source larger than the existing root.
- unsigned Scale = WideSizeInBits / RootSizeInBits;
if (WideSizeInBits <= RootSizeInBits ||
(WideSizeInBits % RootSizeInBits) != 0)
return SDValue();
// Create new mask for larger type.
- SmallVector<int, 64> WideMask(BaseMask);
- for (int &M : WideMask) {
- if (M < 0)
- continue;
- M = (M % NumMaskElts) + ((M / NumMaskElts) * Scale * NumMaskElts);
- }
- WideMask.append((Scale - 1) * NumMaskElts, SM_SentinelUndef);
+ SmallVector<int, 64> WideMask;
+ growShuffleMask(BaseMask, WideMask, RootSizeInBits, WideSizeInBits);
// Attempt to peek through inputs and adjust mask when we extract from an
// upper subvector.
