[clang] [llvm] [NVPTX] Support i256 load/store with 256-bit vector load (PR #155198)

[Artem Belevich via llvm-commits]

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@@ -198,6 +198,12 @@ static bool IsPTXVectorType(MVT VT) {
 static std::optional<std::pair<unsigned int, MVT>>
 getVectorLoweringShape(EVT VectorEVT, const NVPTXSubtarget &STI,
                        unsigned AddressSpace) {
+  const bool CanLowerTo256Bit = STI.has256BitVectorLoadStore(AddressSpace);
+
+  if (CanLowerTo256Bit && VectorEVT.isScalarInteger() &&
+      VectorEVT.getSizeInBits() == 256)
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Artem-B wrote:

Nit: no point checking if 256 bit ld/st are supported if we're operating ont he wrong size. I'd just fold the STI call into the if as the last condition.

https://github.com/llvm/llvm-project/pull/155198