[clang] [X86][clang-cl] Add CL option /vlen (PR #166375)

[Hans Wennborg via cfe-commits]

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@@ -8266,6 +8266,37 @@ void Clang::AddClangCLArgs(const ArgList &Args, types::ID InputType,
                                                      << "/kernel";
  }
 
+  if (Args.hasArg(options::OPT__SLASH_vlen_default)) {
+    // Override /vlen= options.
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zmodem wrote:

Shouldn't the last flag take precedence? For example, in `/arch:AVX512 /vlen /vlen=256`, shouldn't 256 win? What does MSVC do?

https://github.com/llvm/llvm-project/pull/166375