[VectorUtils] rename scaleShuffleMask to narrowShuffleMaskElts; NFC
As proposed in D77881, we'll have the related widening operation,
so this name becomes too vague.
While here, change the function signature to take an 'int' rather
than 'size_t' for the scaling factor, add an assert for overflow of
32-bits, and improve the documentation comments.
diff --git a/llvm/lib/Analysis/VectorUtils.cpp b/llvm/lib/Analysis/VectorUtils.cpp
index 5468794..a5fa3ec 100644
--- a/llvm/lib/Analysis/VectorUtils.cpp
+++ b/llvm/lib/Analysis/VectorUtils.cpp
@@ -398,8 +398,8 @@
return false;
}
-void llvm::scaleShuffleMask(size_t Scale, ArrayRef<int> Mask,
- SmallVectorImpl<int> &ScaledMask) {
+void llvm::narrowShuffleMaskElts(int Scale, ArrayRef<int> Mask,
+ SmallVectorImpl<int> &ScaledMask) {
assert(Scale > 0 && "Unexpected scaling factor");
// Fast-path: if no scaling, then it is just a copy.
@@ -409,9 +409,15 @@
}
ScaledMask.clear();
- for (int MaskElt : Mask)
- for (int ScaleElt = 0; ScaleElt != (int)Scale; ++ScaleElt)
- ScaledMask.push_back(MaskElt < 0 ? MaskElt : Scale * MaskElt + ScaleElt);
+ for (int MaskElt : Mask) {
+ if (MaskElt >= 0) {
+ assert(((uint64_t)Scale * MaskElt + (Scale - 1)) <=
+ std::numeric_limits<int32_t>::max() &&
+ "Overflowed 32-bits");
+ }
+ for (int SliceElt = 0; SliceElt != Scale; ++SliceElt)
+ ScaledMask.push_back(MaskElt < 0 ? MaskElt : Scale * MaskElt + SliceElt);
+ }
}
MapVector<Instruction *, uint64_t>
