diff --git a/libc/cmake/modules/LLVMLibCCheckCpuFeatures.cmake b/libc/cmake/modules/LLVMLibCCheckCpuFeatures.cmake
--- a/libc/cmake/modules/LLVMLibCCheckCpuFeatures.cmake
+++ b/libc/cmake/modules/LLVMLibCCheckCpuFeatures.cmake
@@ -14,6 +14,8 @@
   set(LIBC_COMPILE_OPTIONS_NATIVE -march=native)
 elseif(${LIBC_TARGET_ARCHITECTURE_IS_AARCH64})
   set(LIBC_COMPILE_OPTIONS_NATIVE -mcpu=native)
+elseif(${LIBC_TARGET_ARCHITECTURE_IS_RISCV64})
+  set(ALL_CPU_FEATURES FMA)
 endif()
 
 # Making sure ALL_CPU_FEATURES is sorted.
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
@@ -134,11 +134,6 @@
 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_CPU_FEATURES MATCHES "FMA")
   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()
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
@@ -38,7 +38,7 @@
       list(APPEND compile_options "-Wstrict-prototypes")
       list(APPEND compile_options "-Wthread-safety")
     endif()
-    if(ADD_FMA_FLAG)
+    if(ADD_FMA_FLAG AND LIBC_TARGET_ARCHITECTURE_IS_X86)
       list(APPEND compile_options "-mavx2")
       list(APPEND compile_options "-mfma")
     endif()
@@ -48,7 +48,7 @@
   elseif(MSVC)
     list(APPEND compile_options "/EHs-c-")
     list(APPEND compile_options "/GR-")
-    if(ADD_FMA_FLAG)
+    if(ADD_FMA_FLAG AND LIBC_TARGET_ARCHITECTURE_IS_X86)
       list(APPEND compile_options "/arch:AVX2")
     endif()
   endif()