Revert "[clang] Remove FEM_Indeterminable" (#137654)

Reverts #137247

Author: ojhunt

clang/include/clang/Basic/FPOptions.def

@@ -24,7 +24,7 @@ OPTION(NoHonorInfs, bool, 1, NoHonorNaNs)
 OPTION(NoSignedZero, bool, 1, NoHonorInfs)
 OPTION(AllowReciprocal, bool, 1, NoSignedZero)
 OPTION(AllowApproxFunc, bool, 1, AllowReciprocal)
-OPTION(FPEvalMethod, LangOptions::FPEvalMethodKind, 2, AllowApproxFunc)
+OPTION(FPEvalMethod, LangOptions::FPEvalMethodKind, 3, AllowApproxFunc)
 OPTION(Float16ExcessPrecision, LangOptions::ExcessPrecisionKind, 2, FPEvalMethod)
 OPTION(BFloat16ExcessPrecision, LangOptions::ExcessPrecisionKind, 2, Float16ExcessPrecision)
 OPTION(MathErrno, bool, 1, BFloat16ExcessPrecision)

clang/include/clang/Basic/LangOptions.def

@@ -347,7 +347,7 @@ BENIGN_ENUM_LANGOPT(DefaultFPContractMode, FPModeKind, 2, FPM_Off, "FP contracti
 COMPATIBLE_LANGOPT(ExpStrictFP, 1, false, "Enable experimental strict floating point")
 BENIGN_LANGOPT(RoundingMath, 1, false, "Do not assume default floating-point rounding behavior")
 BENIGN_ENUM_LANGOPT(FPExceptionMode, FPExceptionModeKind, 2, FPE_Default, "FP Exception Behavior Mode type")
-BENIGN_ENUM_LANGOPT(FPEvalMethod, FPEvalMethodKind, 2, FEM_UnsetOnCommandLine, "FP type used for floating point arithmetic")
+BENIGN_ENUM_LANGOPT(FPEvalMethod, FPEvalMethodKind, 3, FEM_UnsetOnCommandLine, "FP type used for floating point arithmetic")
 ENUM_LANGOPT(Float16ExcessPrecision, ExcessPrecisionKind, 2, FPP_Standard, "Intermediate truncation behavior for Float16 arithmetic")
 ENUM_LANGOPT(BFloat16ExcessPrecision, ExcessPrecisionKind, 2, FPP_Standard, "Intermediate truncation behavior for BFloat16 arithmetic")
 LANGOPT(NoBitFieldTypeAlign , 1, 0, "bit-field type alignment")

clang/include/clang/Basic/LangOptions.h

@@ -304,7 +304,10 @@ class LangOptionsBase {
   };
 
   /// Possible float expression evaluation method choices.
-  enum FPEvalMethodKind : unsigned {
+  enum FPEvalMethodKind {
+    /// The evaluation method cannot be determined or is inconsistent for this
+    /// target.
+    FEM_Indeterminable = -1,
     /// Use the declared type for fp arithmetic.
     FEM_Source = 0,
     /// Use the type double for fp arithmetic.