[llvm] [Matrix] Use data layout index type for lowering matrix intrinsics (PR #162646)

[Florian Hahn via llvm-commits]

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@@ -241,11 +241,16 @@ raw_ostream &operator<<(raw_ostream &OS, ShapeInfo SI) {
 
 } // namespace
 
-static bool isUniformShape(Value *V) {
+/// Returns true if \p V is an instruction whose result is of the same shape
+/// as its operands (or if \p V is a non-instruction value).
+static bool isShapePreserving(Value *V) {
   Instruction *I = dyn_cast<Instruction>(V);
   if (!I)
     return true;
 
+  if (isa<SelectInst>(I))
+    return true;
+
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fhahn wrote:

those changes are unrelated to adjusting the index type. Generally we prefer independent patches for independent changes

https://github.com/llvm/llvm-project/pull/162646