[Driver] Add f16 support to -mrecip parsing.

[craig.topper]

Summary

This is a followup to D120158 which added an 'h' suffix to the
backend handling.

[spatel]

LGTM.

AFAIK, these FP reciprocal options have never been officially documented. Would that go under here:
https://clang.llvm.org/docs/UsersManual.html#controlling-code-generation ?

clang/lib/Driver/ToolChains/Clang.cpp

static void ParseMRecip(const Driver &D, const ArgList &Args,
 
   // Each reciprocal type may be enabled or disabled individually.
   // Check each input value for validity, concatenate them all back together,
   // and pass through.
 
   llvm::StringMap<bool> OptionStrings;
   OptionStrings.insert(std::make_pair("divd", false));
   OptionStrings.insert(std::make_pair("divf", false));
+  OptionStrings.insert(std::make_pair("divh", false));
   OptionStrings.insert(std::make_pair("vec-divd", false));
   OptionStrings.insert(std::make_pair("vec-divf", false));
+  OptionStrings.insert(std::make_pair("vec-divh", false));
   OptionStrings.insert(std::make_pair("sqrtd", false));
   OptionStrings.insert(std::make_pair("sqrtf", false));
+  OptionStrings.insert(std::make_pair("sqrth", false));
   OptionStrings.insert(std::make_pair("vec-sqrtd", false));
   OptionStrings.insert(std::make_pair("vec-sqrtf", false));
+  OptionStrings.insert(std::make_pair("vec-sqrth", false));
 
   for (unsigned i = 0; i != NumOptions; ++i) {
     StringRef Val = A->getValue(i);
 
     bool IsDisabled = Val.startswith(DisabledPrefixIn);
     // Ignore the disablement token for string matching.
     if (IsDisabled)
       Val = Val.substr(1);
 
     size_t RefStep;
     if (!getRefinementStep(Val, D, *A, RefStep))
       return;
 
     StringRef ValBase = Val.slice(0, RefStep);
     llvm::StringMap<bool>::iterator OptionIter = OptionStrings.find(ValBase);
     if (OptionIter == OptionStrings.end()) {
       // Try again specifying float suffix.
       OptionIter = OptionStrings.find(ValBase.str() + 'f');
       if (OptionIter == OptionStrings.end()) {
         // The input name did not match any known option string.
         D.Diag(diag::err_drv_unknown_argument) << Val;
         return;
       }
-      // The option was specified without a float or double suffix.
-      // Make sure that the double entry was not already specified.
+      // The option was specified without a half or float or double suffix.
+      // Make sure that the double or half entry was not already specified.
       // The float entry will be checked below.
-      if (OptionStrings[ValBase.str() + 'd']) {
+      if (OptionStrings[ValBase.str() + 'd'] ||
+          OptionStrings[ValBase.str() + 'h']) {
         D.Diag(diag::err_drv_invalid_value) << A->getOption().getName() << Val;
         return;
       }
     }
 
     if (OptionIter->second == true) {
       // Duplicate option specified.
       D.Diag(diag::err_drv_invalid_value) << A->getOption().getName() << Val;
       return;
     }
 
     // Mark the matched option as found. Do not allow duplicate specifiers.
     OptionIter->second = true;
 
-    // If the precision was not specified, also mark the double entry as found.
-    if (ValBase.back() != 'f' && ValBase.back() != 'd')
+    // If the precision was not specified, also mark the double and half entry
+    // as found.
+    if (ValBase.back() != 'f' && ValBase.back() != 'd' && ValBase.back() != 'h') {
       OptionStrings[ValBase.str() + 'd'] = true;
+      OptionStrings[ValBase.str() + 'h'] = true;
+    }
 
     // Build the output string.
     StringRef Prefix = IsDisabled ? DisabledPrefixOut : EnabledPrefixOut;
     Out = Args.MakeArgString(Out + Prefix + Val);
     if (i != NumOptions - 1)
       Out = Args.MakeArgString(Out + ",");
   }
 

clang/test/CodeGen/attr-mrecip.c

-// RUN: %clang_cc1 -mrecip=!sqrtf,vec-divf:3 -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -mrecip=!sqrtf,vec-divf:3,divh -emit-llvm %s -o - | FileCheck %s
 
 int baz(int a) { return 4; }
 
 // CHECK: baz{{.*}} #0
-// CHECK: #0 = {{.*}}"reciprocal-estimates"="!sqrtf,vec-divf:3"
+// CHECK: #0 = {{.*}}"reciprocal-estimates"="!sqrtf,vec-divf:3,divh"
 

clang/test/Driver/mrecip.c

 // RECIP6: "-mrecip=vec-sqrtd"
 
 // RUN: %clang -### -S %s -mrecip=!divf  2>&1 | FileCheck --check-prefix=RECIP7 %s
 // RECIP7: "-mrecip=!divf"
 
 // RUN: %clang -### -S %s -mrecip=divf,sqrtd,vec-divd,vec-sqrtf  2>&1 | FileCheck --check-prefix=RECIP8 %s
 // RECIP8: "-mrecip=divf,sqrtd,vec-divd,vec-sqrtf"
 
+// RUN: %clang -### -S %s -mrecip=vec-sqrth  2>&1 | FileCheck --check-prefix=RECIP18 %s
+// RECIP18: "-mrecip=vec-sqrth"
+
 //// Check optional refinement step specifiers.
 
 // RUN: %clang -### -S %s -mrecip=all:1  2>&1 | FileCheck --check-prefix=RECIP9 %s
 // RECIP9: "-mrecip=all:1"
 
 // RUN: %clang -### -S %s -mrecip=sqrtf:3  2>&1 | FileCheck --check-prefix=RECIP10 %s
 // RECIP10: "-mrecip=sqrtf:3"
 
 // RUN: %clang -### -S %s -mrecip=div:5  2>&1 | FileCheck --check-prefix=RECIP11 %s
 // RECIP11: "-mrecip=div:5"
 
 // RUN: %clang -### -S %s -mrecip=divd:1,!sqrtf:2,vec-divf:9,vec-sqrtd:0  2>&1 | FileCheck --check-prefix=RECIP12 %s
 // RECIP12: "-mrecip=divd:1,!sqrtf:2,vec-divf:9,vec-sqrtd:0"
 
+// RUN: %clang -### -S %s -mrecip=sqrth:2  2>&1 | FileCheck --check-prefix=RECIP19 %s
+// RECIP19: "-mrecip=sqrth:2"
+
 //// Check invalid parameters.
 
 // RUN: %clang -### -S %s -mrecip=bogus  2>&1 | FileCheck --check-prefix=RECIP13 %s
 // RECIP13: error: unknown argument
 
 // RUN: %clang -### -S %s -mrecip=divd:1,divd  2>&1 | FileCheck --check-prefix=RECIP14 %s
 // RECIP14: error: invalid value 
 
 // RUN: %clang -### -S %s -mrecip=sqrt,sqrtf  2>&1 | FileCheck --check-prefix=RECIP15 %s
 // RECIP15: error: invalid value 
 
 // RUN: %clang -### -S %s -mrecip=+default:10  2>&1 | FileCheck --check-prefix=RECIP16 %s
 // RECIP16: error: invalid value 
 
 // RUN: %clang -### -S %s -mrecip=!vec-divd:  2>&1 | FileCheck --check-prefix=RECIP17 %s
 // RECIP17: error: invalid value 
 
+// RUN: %clang -### -S %s -mrecip=divh:1,divh  2>&1 | FileCheck --check-prefix=RECIP20 %s
+// RECIP20: error: invalid value 
+
+// RUN: %clang -### -S %s -mrecip=divh,div  2>&1 | FileCheck --check-prefix=RECIP21 %s
+// RECIP21: error: invalid value 
+
+// RUN: %clang -### -S %s -mrecip=sqrt,sqrth  2>&1 | FileCheck --check-prefix=RECIP22 %s
+// RECIP22: error: invalid value