[libc][RISCV] Let RISCV64 targets test implementations with and without FMA.

[lntue]

Summary

Let RISCV64 targets math implementations with and without FMA
automatically.

[michaelrj]

LGTM

libc/cmake/modules/LLVMLibCFlagRules.cmake

function(get_fq_dep_list_without_flag output_list flag)
   set(${output_list} ${fq_dep_no_flag_list} PARENT_SCOPE)
 endfunction(get_fq_dep_list_without_flag)
 
 # Special flags
 set(FMA_OPT_FLAG "FMA_OPT")
 set(ROUND_OPT_FLAG "ROUND_OPT")
 
 # Skip FMA_OPT flag for targets that don't support fma.
-if(NOT(LIBC_TARGET_ARCHITECTURE_IS_X86 AND (LIBC_CPU_FEATURES MATCHES "FMA")))
+if(NOT((LIBC_TARGET_ARCHITECTURE_IS_X86 AND (LIBC_CPU_FEATURES MATCHES "FMA")) OR
+       LIBC_TARGET_ARCHITECTURE_IS_RISCV64))
   set(SKIP_FLAG_EXPANSION_FMA_OPT TRUE)
 endif()
 
 # Skip ROUND_OPT flag for targets that don't support SSE 4.2.
 if(NOT(LIBC_TARGET_ARCHITECTURE_IS_X86 AND (LIBC_CPU_FEATURES MATCHES "SSE4_2")))
   set(SKIP_FLAG_EXPANSION_ROUND_OPT TRUE)
 endif()

libc/cmake/modules/LLVMLibCObjectRules.cmake

 set(OBJECT_LIBRARY_TARGET_TYPE "OBJECT_LIBRARY")
 
 function(_get_common_compile_options output_var flags)
   list(FIND flags ${FMA_OPT_FLAG} fma)
   if(${fma} LESS 0)
     list(FIND flags "${FMA_OPT_FLAG}__ONLY" fma)
   endif()
-  if((${fma} GREATER -1) AND (LIBC_CPU_FEATURES MATCHES "FMA"))
+  if((${fma} GREATER -1) AND (LIBC_TARGET_ARCHITECTURE_IS_RISCV64 OR
+                              (LIBC_CPU_FEATURES MATCHES "FMA")))
     set(ADD_FMA_FLAG TRUE)
   endif()
 
   list(FIND flags ${ROUND_OPT_FLAG} round)
   if(${round} LESS 0)
     list(FIND flags "${ROUND_OPT_FLAG}__ONLY" round)
   endif()
   if((${round} GREATER -1) AND (LIBC_CPU_FEATURES MATCHES "SSE4_2"))
if(LLVM_COMPILER_IS_GCC_COMPATIBLE)
     list(APPEND compile_options "-Wextra-semi")
     if(NOT CMAKE_COMPILER_IS_GNUCXX)
       list(APPEND compile_options "-Wnewline-eof")
       list(APPEND compile_options "-Wnonportable-system-include-path")
       list(APPEND compile_options "-Wstrict-prototypes")
       list(APPEND compile_options "-Wthread-safety")
     endif()
     if(ADD_FMA_FLAG)
+      if(LIBC_TARGET_ARCHITECTURE_IS_X86)
         list(APPEND compile_options "-mavx2")
         list(APPEND compile_options "-mfma")
+      elseif(LIBC_TARGET_ARCHITECTURE_IS_RISCV64)
+        list(APPEND compile_option "-D__LIBC_RISCV_USE_FMA")
+      endif()
     endif()
     if(ADD_SSE4_2_FLAG)
       list(APPEND compile_options "-msse4.2")
     endif()
   elseif(MSVC)
     list(APPEND compile_options "/EHs-c-")
     list(APPEND compile_options "/GR-")
     if(ADD_FMA_FLAG)

libc/src/__support/macros/properties/cpu_features.h

 #define LIBC_TARGET_CPU_HAS_AVX512F
 #endif
 
 #if defined(__AVX512BW__)
 #define LIBC_TARGET_CPU_HAS_AVX512BW
 #endif
 
 #if defined(__ARM_FEATURE_FMA) || defined(__AVX2__) || defined(__FMA__) ||     \
-    defined(__riscv)
+    defined(__LIBC_RISCV_USE_FMA)
 #define LIBC_TARGET_CPU_HAS_FMA
 #endif
 
 #endif // LLVM_LIBC_SRC_SUPPORT_MACROS_PROPERTIES_CPU_FEATURES_H