[clang] [Matrix] Add a row\col major toggle in the clang driver (PR #167628)

[Farzon Lotfi via cfe-commits]

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@@ -0,0 +1,35 @@
+// RUN: %clang --target=x86_64-linux-gnu -fenable-matrix -fmatrix-memory-layout=column-major %s -### 2>&1 | FileCheck %s --check-prefix=CHECK-COL-MAJOR
+// CHECK-COL-MAJOR:  -fenable-matrix
+// CHECK-COL-MAJOR:  -mllvm
+// CHECK-COL-MAJOR:  -enable-matrix
+// CHECK-COL-MAJOR:  -fmatrix-memory-layout=column-major
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farzonl wrote:

 I removed the use of the flags llvm needs for the lower-matrix-intrinsics pass based on @cofibrant  feedback. There was concerns it was premature to change `-mllvm matrix-default-layout=*` before the row major load/store intrinsics were implemented. 

https://github.com/llvm/llvm-project/pull/167628