Revert "[clang] Revert default behavior change of P0522R0 implementation (#91811)"

With blocking issues fixed, re-enable relaxed template template argument matching
by reverting these commits.

This reverts commit 4198aeb.
This reverts commit 2d5634a.

Author: mizvekov

clang/lib/Driver/ToolChains/Clang.cpp

@@ -7249,15 +7249,15 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
   Args.addOptOutFlag(CmdArgs, options::OPT_fassume_unique_vtables,
                      options::OPT_fno_assume_unique_vtables);
 
-  // -fno-relaxed-template-template-args is deprecated.
-  if (Arg *A = Args.getLastArg(options::OPT_frelaxed_template_template_args,
-                               options::OPT_fno_relaxed_template_template_args);
-      A &&
-      A->getOption().matches(options::OPT_fno_relaxed_template_template_args))
+  // -frelaxed-template-template-args is deprecated.
+  if (Arg *A =
+          Args.getLastArg(options::OPT_frelaxed_template_template_args,
+                          options::OPT_fno_relaxed_template_template_args)) {
     D.Diag(diag::warn_drv_deprecated_arg)
         << A->getAsString(Args) << /*hasReplacement=*/false;
-  else
-    CmdArgs.push_back("-fno-relaxed-template-template-args");
+    if (A->getOption().matches(options::OPT_fno_relaxed_template_template_args))
+      CmdArgs.push_back("-fno-relaxed-template-template-args");
+  }
 
   // -fsized-deallocation is off by default, as it is an ABI-breaking change for
   // most platforms.

clang/test/Driver/frelaxed-template-template-args.cpp

@@ -1,7 +1,7 @@
 // RUN: %clang -fsyntax-only -### %s 2>&1 | FileCheck --check-prefix=CHECK-DEF %s
-// RUN: %clang -fsyntax-only -frelaxed-template-template-args %s 2>&1 | FileCheck --check-prefix=CHECK-ON --allow-empty %s
+// RUN: %clang -fsyntax-only -frelaxed-template-template-args %s 2>&1 | FileCheck --check-prefix=CHECK-ON %s
 // RUN: %clang -fsyntax-only -fno-relaxed-template-template-args %s 2>&1 | FileCheck --check-prefix=CHECK-OFF %s
 
-// CHECK-DEF: "-cc1"{{.*}} "-fno-relaxed-template-template-args"
-// CHECK-ON-NOT: warning: argument '-frelaxed-template-template-args' is deprecated [-Wdeprecated]
+// CHECK-DEF-NOT: "-cc1"{{.*}} "-fno-relaxed-template-template-args"
+// CHECK-ON:  warning: argument '-frelaxed-template-template-args' is deprecated [-Wdeprecated]
 // CHECK-OFF: warning: argument '-fno-relaxed-template-template-args' is deprecated [-Wdeprecated]

clang/test/Driver/rewrite-legacy-objc.m

@@ -3,11 +3,11 @@
 // TEST0: "-cc1"
 // TEST0: "-rewrite-objc"
 // FIXME: CHECK-NOT is broken somehow, it doesn't work here. Check adjacency instead.
-// TEST0: "-stack-protector" "1" "-fblocks" "-fencode-extended-block-signature" "-fregister-global-dtors-with-atexit" "-fgnuc-version=4.2.1"{{.*}} "-fobjc-runtime=macosx-fragile" "-fno-objc-infer-related-result-type" "-fobjc-exceptions" "-fexceptions" "-fno-relaxed-template-template-args" "-fmax-type-align=16"
+// TEST0: "-stack-protector" "1" "-fblocks" "-fencode-extended-block-signature" "-fregister-global-dtors-with-atexit" "-fgnuc-version=4.2.1"{{.*}} "-fobjc-runtime=macosx-fragile" "-fno-objc-infer-related-result-type" "-fobjc-exceptions" "-fexceptions" "-fmax-type-align=16"
 // TEST0: rewrite-legacy-objc.m"
 // RUN: %clang --target=i386-apple-macosx10.9.0 -rewrite-legacy-objc %s -o - -### 2>&1 | \
 // RUN:   FileCheck -check-prefix=TEST1 %s
 // RUN: %clang --target=i386-apple-macosx10.6.0 -rewrite-legacy-objc %s -o - -### 2>&1 | \
 // RUN:   FileCheck -check-prefix=TEST2 %s
-// TEST1: "-stack-protector" "1" "-fblocks" "-fencode-extended-block-signature" "-fregister-global-dtors-with-atexit" "-fgnuc-version=4.2.1"{{.*}} "-fobjc-runtime=macosx-fragile" "-fobjc-subscripting-legacy-runtime" "-fno-objc-infer-related-result-type" "-fobjc-exceptions" "-fno-relaxed-template-template-args" "-fmax-type-align=16"
-// TEST2: "-stack-protector" "1" "-fblocks" "-fencode-extended-block-signature" "-fregister-global-dtors-with-atexit" "-fgnuc-version=4.2.1"{{.*}} "-fobjc-runtime=macosx-fragile" "-fobjc-subscripting-legacy-runtime" "-fno-objc-infer-related-result-type" "-fobjc-exceptions" "-fno-relaxed-template-template-args" "-fmax-type-align=16"
+// TEST1: "-stack-protector" "1" "-fblocks" "-fencode-extended-block-signature" "-fregister-global-dtors-with-atexit" "-fgnuc-version=4.2.1"{{.*}} "-fobjc-runtime=macosx-fragile" "-fobjc-subscripting-legacy-runtime" "-fno-objc-infer-related-result-type" "-fobjc-exceptions" "-fmax-type-align=16"
+// TEST2: "-stack-protector" "1" "-fblocks" "-fencode-extended-block-signature" "-fregister-global-dtors-with-atexit" "-fgnuc-version=4.2.1"{{.*}} "-fobjc-runtime=macosx-fragile" "-fobjc-subscripting-legacy-runtime" "-fno-objc-infer-related-result-type" "-fobjc-exceptions" "-fmax-type-align=16"

clang/test/Driver/rewrite-objc.m

@@ -2,4 +2,4 @@
 // RUN:   FileCheck -check-prefix=TEST0 %s
 // TEST0: "-cc1" {{.*}} "-rewrite-objc"
 // FIXME: CHECK-NOT is broken somehow, it doesn't work here. Check adjacency instead.
-// TEST0: "-stack-protector" "1" "-fblocks" "-fencode-extended-block-signature" "-fregister-global-dtors-with-atexit" "-fgnuc-version=4.2.1"{{.*}} "-fobjc-runtime=macosx" "-fno-objc-infer-related-result-type" "-fobjc-exceptions" "-fexceptions" "-fno-relaxed-template-template-args" "-fmax-type-align=16"
+// TEST0: "-stack-protector" "1" "-fblocks" "-fencode-extended-block-signature" "-fregister-global-dtors-with-atexit" "-fgnuc-version=4.2.1"{{.*}} "-fobjc-runtime=macosx" "-fno-objc-infer-related-result-type" "-fobjc-exceptions" "-fexceptions" "-fmax-type-align=16"