[clang] [Clang][HLSL] Keep matrix SSA values in column-major order (PR #227087)

[Sarah Spall via cfe-commits]

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@@ -2364,11 +2364,8 @@ LValue CodeGenFunction::EmitMatrixElementExpr(const MatrixElementExpr *E) {
     llvm::Value *Mat = EmitScalarExpr(E->getBase());
     Address MatMem = CreateMemTemp(E->getBase()->getType());
     QualType Ty = E->getBase()->getType();
-    llvm::Type *LTy = convertTypeForLoadStore(Ty, Mat->getType());
-    if (LTy->getScalarSizeInBits() > Mat->getType()->getScalarSizeInBits())
-      Mat = Builder.CreateZExt(Mat, LTy);
-    Builder.CreateStore(Mat, MatMem);
     Base = MakeAddrLValue(MatMem, Ty, AlignmentSource::Decl);
+    EmitStoreOfScalar(Mat, Base, /*isInit=*/true);
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spall wrote:

could we just call EmitStoreOfMatrixScalar here instead to remove a layer of indirection? It looks like this code path is guaranteed to call it via EmitStoreOfScalar?

https://github.com/llvm/llvm-project/pull/227087