[llvm] [LoongArch] Type legalize v2f32 loads by using an f64 load and a scalar_to_vector (PR #164943)

[via llvm-commits]

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@@ -4668,6 +4670,32 @@ void LoongArchTargetLowering::ReplaceNodeResults(
            "Unexpected custom legalisation");
     Results.push_back(customLegalizeToWOp(N, DAG, 2));
     break;
+  case ISD::LOAD: {
+    // Use an f64 load and a scalar_to_vector for v2f32 loads. This avoids
+    // scalarizing in 32-bit mode. In 64-bit mode this avoids a int->fp
+    // cast since type legalization will try to use an i64 load.
+    MVT VT = N->getSimpleValueType(0);
+    assert(VT == MVT::v2f32 && "Unexpected VT");
+    assert(getTypeAction(*DAG.getContext(), VT) == TypeWidenVector &&
+           "Unexpected type action!");
+    if (!ISD::isNON_EXTLoad(N))
+      return;
+    auto *Ld = cast<LoadSDNode>(N);
+    if (Subtarget.hasExtLSX()) {
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zhaoqi5 wrote:

This maybe unnecessary?

https://github.com/llvm/llvm-project/pull/164943