Fixes#172711
Fixes the type mismatch issues preventing single matrix subscript
getters and setters from working with boolean matrices.
The changes from this PR also happens to make matrix splats work for
boolean matrices, but adding tests for that and (re)introducing
boolean-matrix-specific sema will be relegated to its own PR.
This change creates an XFAIL that will be addressed by #172805
This part of the change was not intended to make it in. It was a way to
optimize for constant index setters\getters but had the unintended
consequence of doing swizzles without considering the encoded element
offsets.
We need to be calling `MakeExtVectorElt` in `EmitExtVectorElementExpr`
so that we can call `E->getEncodedElementAccess(Elts);` off of the
`ExtVectorElementExpr` Node.
Calling it in `EmitMatrixSingleSubscriptExpr` was wrong because we doing
have the vector encoded elementts yet. But also to get the right index
we need a way to pass on the matrix column and row lengths so
`MakeMatrixRow` needed to be expanded to store row and column sizes on
the LValue.
fixes#166206
- Add swizzle support if row index is constant
- Add test cases
- Add new AST type
- Add new LValue for Matrix Row Type
- TODO: Make the new LValue a dynamic index version of ExtVectorElt
