Pragma `clang fp eval_method` needs to take as input a supported value.

[zahiraam]

Summary

Diagnose when #pragma clang fp eval_method doesn't have a supported value. Currently the compiler is crashing.

[aaron.ballman]

LGTM with a tiny tweak to the diagnostic.

clang/include/clang/Basic/DiagnosticParseKinds.td

1493

Slight tweak here to use a list instead of multiple ors.

clang/include/clang/Basic/DiagnosticParseKinds.td

 
 def err_pragma_fp_invalid_option : Error<
   "%select{invalid|missing}0 option%select{ %1|}0; expected 'contract', 'reassociate' or 'exceptions'">;
 def err_pragma_fp_invalid_argument : Error<
   "unexpected argument '%0' to '#pragma clang fp %1'; expected "
   "%select{"
   "'fast' or 'on' or 'off'|"
   "'on' or 'off'|"
-  "'ignore', 'maytrap' or 'strict'}2">;
+  "'ignore', 'maytrap' or 'strict'|"
+  "'source', 'double' or 'extended'}2">;
 
 def err_pragma_invalid_keyword : Error<
   "invalid argument; expected 'enable'%select{|, 'full'}0%select{|, 'assume_safety'}1 or 'disable'">;
 def err_pragma_pipeline_invalid_keyword : Error<
     "invalid argument; expected 'disable'">;
 
 // Pragma unroll support.
 def warn_pragma_unroll_cuda_value_in_parens : Warning<

clang/test/Sema/fp-eval-pragma.cpp

#pragma clang fp eval_method(double)
   printf("FP: %d\n", __FLT_EVAL_METHOD__);
 }
 
 int foo2() {
   apply_pragma();
   return 0;
 }
 
+void apply_pragma_with_wrong_value() {
+  // expected-error@+1{{unexpected argument 'value' to '#pragma clang fp eval_method'; expected 'source', 'double' or 'extended'}}
+#pragma clang fp eval_method(value)
+}
+
+int foo3() {
+  apply_pragma_with_wrong_value();
+  return 0;
+}
+
 void foo() {
   auto a = __FLT_EVAL_METHOD__;
   {
     // expected-note@+1{{#pragma entered here}}
 #pragma clang fp eval_method(double)
     // expected-error@+1{{'__FLT_EVAL_METHOD__' cannot be expanded inside a scope containing '#pragma clang fp eval_method'}}
     auto b = __FLT_EVAL_METHOD__;
   }