[clang] [flang]Add vscale argument parsing (PR #67676)

[Mats Petersson via cfe-commits]

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@@ -170,6 +170,39 @@ void Flang::addPicOptions(const ArgList &Args, ArgStringList &CmdArgs) const {
   }
 }
 
+
+void Flang::AddAArch64TargetArgs(const ArgList &Args,
+                                 ArgStringList &CmdArgs) const {
+  // Handle -msve_vector_bits=<bits>
+  if (Arg *A = Args.getLastArg(options::OPT_msve_vector_bits_EQ)) {
+    StringRef Val = A->getValue();
+    const Driver &D = getToolChain().getDriver();
+    if (Val.equals("128") || Val.equals("256") || Val.equals("512") ||
+        Val.equals("1024") || Val.equals("2048") || Val.equals("128+") ||
+        Val.equals("256+") || Val.equals("512+") || Val.equals("1024+") ||
+        Val.equals("2048+")) {
+      unsigned Bits = 0;
+      if (Val.endswith("+"))
+        Val = Val.substr(0, Val.size() - 1);
+      else {
+        bool Invalid = Val.getAsInteger(10, Bits); (void)Invalid;
+        assert(!Invalid && "Failed to parse value");
+        CmdArgs.push_back(
+            Args.MakeArgString("-mvscale-max=" + llvm::Twine(Bits / 128)));
+      }
+
+      bool Invalid = Val.getAsInteger(10, Bits); (void)Invalid;
+      assert(!Invalid && "Failed to parse value");
+      CmdArgs.push_back(
+          Args.MakeArgString("-mvscale-min=" + llvm::Twine(Bits / 128)));
+    // Silently drop requests for vector-length agnostic code as it's implied.
+    } else if (!Val.equals("scalable"))
+      // Handle the unsupported values passed to msve-vector-bits.
+      D.Diag(diag::err_drv_unsupported_option_argument)
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Leporacanthicus wrote:

It's not "unsupported", it just doesn't do anything different from "not specifying anything". It's what clang does.

https://github.com/llvm/llvm-project/pull/67676