[llvm] [GISel] Lower scalar G_SELECT in LegalizerHelper (PR #79342)

[Kai Nacke via llvm-commits]

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@@ -7972,13 +7971,22 @@ LegalizerHelper::LegalizeResult LegalizerHelper::lowerSelect(MachineInstr &MI) {
       MaskElt = MIRBuilder.buildSExtInReg(MaskTy, MaskElt, 1).getReg(0);
 
     // Continue the sign extension (or truncate) to match the data type.
-    MaskElt = MIRBuilder.buildSExtOrTrunc(DstTy.getElementType(),
-                                          MaskElt).getReg(0);
+    MaskElt =
+        MIRBuilder
+            .buildSExtOrTrunc(DstTy.isVector() ? DstTy.getElementType() : DstTy,
+                              MaskElt)
+            .getReg(0);
 
-    // Generate a vector splat idiom.
-    auto ShufSplat = MIRBuilder.buildShuffleSplat(DstTy, MaskElt);
-    MaskReg = ShufSplat.getReg(0);
+    if (DstTy.isVector()) {
+      // Generate a vector splat idiom.
+      auto ShufSplat = MIRBuilder.buildShuffleSplat(DstTy, MaskElt);
+      MaskReg = ShufSplat.getReg(0);
+    } else
+      MaskReg = MaskElt;
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redstar wrote:

Changed.

https://github.com/llvm/llvm-project/pull/79342