[clang] [llvm] [AArch64][Driver] Fix behavior of +nofeat modifier on -mcpu (PR #203458)

[via cfe-commits]

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@@ -340,14 +340,22 @@ void AArch64::ExtensionSet::disable(ArchExtKind E) {
       disable(Dep.Later);
 }
 
+static void setEnableIfMandatory(AArch64::ExtensionSet &Exts,
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yamash-fj wrote:

Using ``ExtensionSet::addArchDefaults`` results in emitting redundant ``+<feat>`` for the feature that is implied by only the base-architecture. To keep the cc1 command line concise, I chose to use Enabled.set() instead. I'm not sure which behavior is preferable. Do you think an implementation based on ExtensionSet::addArchDefaults() would be the better approach?


https://github.com/llvm/llvm-project/pull/203458