diff --git a/gcc/config/riscv/arch-canonicalize b/gcc/config/riscv/arch-canonicalize
index 41bab69193ce..c6b357b70cfd 100755
--- a/gcc/config/riscv/arch-canonicalize
+++ b/gcc/config/riscv/arch-canonicalize
@@ -70,10 +70,8 @@ def arch_canonicalize(arch, isa_spec):
   is_isa_spec_2p2 = isa_spec == '2.2'
   new_arch = ""
   extra_long_ext = []
-  std_exts = []
   if arch[:5] in ['rv32e', 'rv32i', 'rv32g', 'rv64i', 'rv64g']:
-    new_arch = arch[:5].replace("g", "i")
-    std_exts = ['m', 'a', 'f', 'd']
+    new_arch = arch[:5].replace("g", "imafd")
     if arch[:5] in ['rv32g', 'rv64g']:
       if not is_isa_spec_2p2:
         extra_long_ext = ['zicsr', 'zifencei']
@@ -88,10 +86,10 @@ def arch_canonicalize(arch, isa_spec):
   if long_ext_prefixes_idx:
     first_long_ext_idx = min(long_ext_prefixes_idx)
     long_exts = arch[first_long_ext_idx:].split("_")
-    std_exts += list(arch[5:first_long_ext_idx])
+    std_exts = list(arch[5:first_long_ext_idx])
   else:
     long_exts = []
-    std_exts += list(arch[5:])
+    std_exts = list(arch[5:])
 
   long_exts += extra_long_ext
 
@@ -136,7 +134,7 @@ def arch_canonicalize(arch, isa_spec):
 
   # Put extensions in canonical order.
   for ext in CANONICAL_ORDER:
-    if ext in std_exts:
+    if ext in std_exts and ext not in new_arch:
       new_arch += ext
 
   # Check every extension is processed.