[clang] [RISCV] Overwrite cpu target features for full arch string in target attribute (PR #77426)

[Craig Topper via cfe-commits]

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@@ -413,7 +385,9 @@ static void handleFullArchString(StringRef FullArchStr,
     // Forward the invalid FullArchStr.
     Features.push_back("+" + FullArchStr.str());
   } else {
-    std::vector<std::string> FeatStrings = (*RII)->toFeatures();
+    // Append a full list of features, including any negative extensions so that
+    // we override the CPU's features.
+    std::vector<std::string> FeatStrings = (*RII)->toFeatures(true);
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topperc wrote:

Add an inline comment to label what `true` means

https://github.com/llvm/llvm-project/pull/77426