[clang] [flang] [mlir] [flang] Add support for -mprefer-vector-width=<value> (PR #141380)

[Cameron McInally via cfe-commits]

================
@@ -2636,6 +2636,10 @@ void ModuleImport::processFunctionAttributes(llvm::Function *func,
     funcOp.setTargetFeaturesAttr(
         LLVM::TargetFeaturesAttr::get(context, attr.getValueAsString()));
 
+  if (llvm::Attribute attr = func->getFnAttribute("prefer-vector-width");
+      attr.isStringAttribute())
+    funcOp.setPreferVectorWidth(attr.getValueAsString());
----------------
mcinally wrote:

Added tests and updated formatting. 👍 👍 

https://github.com/llvm/llvm-project/pull/141380