[clang] [llvm] [AArch64TargetParser]Fix reconstructFromParsedFeatures ignoring negative features (PR #142236)

[Alexandros Lamprineas via llvm-commits]

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@@ -1831,6 +1831,22 @@ TEST_P(AArch64ExtensionDependenciesBaseCPUTestFixture,
   }
 }
 
+TEST(TargetParserTest, testAArch64ReconstructFromParsedFeatures) {
+  AArch64::ExtensionSet Extensions;
+  std::vector<std::string> FeatureOptions = {
+      "-sve2", "-Baz", "+sve", "+FooBar", "+sve2", "+neon", "-sve",
+  };
+  std::vector<std::string> NonExtensions;
+  Extensions.reconstructFromParsedFeatures(FeatureOptions, NonExtensions);
+
+  std::vector<std::string> NonExtensionsExpected = {"-Baz", "+FooBar"};
+  ASSERT_THAT(NonExtensions, testing::ContainerEq(NonExtensionsExpected));
+  std::vector<StringRef> Features;
+  Extensions.toLLVMFeatureList(Features);
+  std::vector<StringRef> FeaturesExpected = {"+neon", "-sve", "+sve2"};
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labrinea wrote:

Reading the comment https://github.com/llvm/llvm-project/blob/main/llvm/include/llvm/TargetParser/AArch64TargetParser.h#L208 reminded me that it is intentional to not expand dependencies at this stage.

https://github.com/llvm/llvm-project/pull/142236