[llvm] [Matrix] Propagate shape information through PHI insts (PR #141681)

[Jon Roelofs via llvm-commits]

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@@ -1313,23 +1348,23 @@ class LowerMatrixIntrinsics {
 
   /// Lower a load instruction with shape information.
   MatrixTy LowerLoad(Instruction *Inst, Value *Ptr, MaybeAlign Align,
-                     Value *Stride, bool IsVolatile, ShapeInfo Shape) {
-    IRBuilder<> Builder(Inst);
+                     Value *Stride, bool IsVolatile, ShapeInfo Shape,
+                     IRBuilder<> &Builder) {
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jroelofs wrote:

It's NFC as far as that PR goes, but necessary for this one re: the SetInsertPoint + comment at the bottom of VisitPHI.

https://github.com/llvm/llvm-project/pull/141681