diff --git a/aclocal.m4 b/aclocal.m4
index d5078de..cf0a0fe 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -216,7 +216,7 @@ AC_DEFUN([FPTOOLS_SET_HASKELL_PLATFORM_VARS],
         mipsel)
             test -z "[$]2" || eval "[$]2=ArchMipsel"
             ;;
-        hppa|hppa1_1|ia64|m68k|rs6000|s390|s390x|sh4|vax)
+        hppa|hppa1_1|ia64|m68k|riscv32|riscv64|rs6000|s390|s390x|sh4|vax)
             test -z "[$]2" || eval "[$]2=ArchUnknown"
             ;;
         *)
@@ -1895,6 +1895,12 @@ case "$1" in
   powerpc*)
     $2="powerpc"
     ;;
+  riscv64*)
+    $2="riscv64"
+    ;;
+  riscv|riscv32*)
+    $2="riscv32"
+    ;;
   rs6000)
     $2="rs6000"
     ;;