[CIR] Fix Lowering/ptrstride.cir xfailed after rebasing

[AmrDeveloper]

Fixing Lit test after rebasing

CIRToLLVMPtrStrideOpLowering will not emit casting in this case because the width is equal to *layoutWidth

clangir/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp

Lines 967 to 999 in d329c96

	if (indexOp && layoutWidth && width != *layoutWidth) {
	// If the index comes from a subtraction, make sure the extension happens
	// before it. To achieve that, look at unary minus, which already got
	// lowered to "sub 0, x".
	auto sub = dyn_cast<mlir::LLVM::SubOp>(indexOp);
	auto unary = dyn_cast_if_present<cir::UnaryOp>(
	ptrStrideOp.getStride().getDefiningOp());
	bool rewriteSub =
	unary && unary.getKind() == cir::UnaryOpKind::Minus && sub;
	if (rewriteSub)
	index = indexOp->getOperand(1);
	// Handle the cast
	auto llvmDstType = mlir::IntegerType::get(ctx, *layoutWidth);
	index = getLLVMIntCast(rewriter, index, llvmDstType,
	ptrStrideOp.getStride().getType().isUnsigned(),
	width, *layoutWidth);
	// Rewrite the sub in front of extensions/trunc
	if (rewriteSub) {
	index = rewriter.create<mlir::LLVM::SubOp>(
	index.getLoc(), index.getType(),
	rewriter.create<mlir::LLVM::ConstantOp>(
	index.getLoc(), index.getType(),
	mlir::IntegerAttr::get(index.getType(), 0)),
	index);
	rewriter.eraseOp(sub);
	}
	}
	rewriter.replaceOpWithNewOp<mlir::LLVM::GEPOp>(
	ptrStrideOp, resultTy, elementTy, adaptor.getBase(), index);
	return mlir::success();

Fixes: #1295

[AmrDeveloper]

Is there a reason to expect a cast instruction in this case? From my understanding should emit GEPOp?

@bcardosolopes, @lanza