diff --git a/libc/cmake/modules/LLVMLibCFlagRules.cmake b/libc/cmake/modules/LLVMLibCFlagRules.cmake
--- a/libc/cmake/modules/LLVMLibCFlagRules.cmake
+++ b/libc/cmake/modules/LLVMLibCFlagRules.cmake
@@ -134,7 +134,8 @@
 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()
 
diff --git a/libc/cmake/modules/LLVMLibCObjectRules.cmake b/libc/cmake/modules/LLVMLibCObjectRules.cmake
--- a/libc/cmake/modules/LLVMLibCObjectRules.cmake
+++ b/libc/cmake/modules/LLVMLibCObjectRules.cmake
@@ -5,7 +5,8 @@
   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()
 
@@ -39,8 +40,12 @@
       list(APPEND compile_options "-Wthread-safety")
     endif()
     if(ADD_FMA_FLAG)
-      list(APPEND compile_options "-mavx2")
-      list(APPEND compile_options "-mfma")
+      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")
diff --git a/libc/src/__support/macros/properties/cpu_features.h b/libc/src/__support/macros/properties/cpu_features.h
--- a/libc/src/__support/macros/properties/cpu_features.h
+++ b/libc/src/__support/macros/properties/cpu_features.h
@@ -37,7 +37,7 @@
 #endif
 
 #if defined(__ARM_FEATURE_FMA) || defined(__AVX2__) || defined(__FMA__) ||     \
-    defined(__riscv)
+    defined(__LIBC_RISCV_USE_FMA)
 #define LIBC_TARGET_CPU_HAS_FMA
 #endif