diff --git a/gcc/common/config/riscv/riscv-common.cc b/gcc/common/config/riscv/riscv-common.cc
index 6091d8f281b..9de7c54269e 100644
--- a/gcc/common/config/riscv/riscv-common.cc
+++ b/gcc/common/config/riscv/riscv-common.cc
@@ -311,6 +311,8 @@ static const char *riscv_tunes[] =
 
 static const char *riscv_supported_std_ext (void);
 
+bool riscv_subset_list::parse_failed = false;
+
 static riscv_subset_list *current_subset_list = NULL;
 
 const riscv_subset_list *riscv_current_subset_list ()
@@ -518,6 +520,18 @@ subset_cmp (const std::string &a, const std::string &b)
     }
 }
 
+/* Return true if EXT is a standard extension.  */
+
+static bool
+standard_extensions_p (const char *ext)
+{
+  const riscv_ext_version *ext_ver;
+  for (ext_ver = &riscv_ext_version_table[0]; ext_ver->name != NULL; ++ext_ver)
+    if (strcmp (ext, ext_ver->name) == 0)
+      return true;
+  return false;
+}
+
 /* Add new subset to list.  */
 
 void
@@ -546,6 +560,38 @@ riscv_subset_list::add (const char *subset, int major_version,
 
       return;
     }
+  else if (strlen (subset) == 1 && !standard_extensions_p (subset))
+    {
+      error_at (m_loc,
+		"%<-march=%s%>: extension %qs is unsupported standard single "
+		"letter extension",
+		m_arch, subset);
+      return;
+    }
+  else if (subset[0] == 'z' && !standard_extensions_p (subset))
+    {
+      error_at (m_loc,
+		"%<-march=%s%>: extension %qs starts with `z` but is "
+		"unsupported standard extension",
+		m_arch, subset);
+      return;
+    }
+  else if (subset[0] == 's' && !standard_extensions_p (subset))
+    {
+      error_at (m_loc,
+		"%<-march=%s%>: extension %qs start with `s` but is "
+		"unsupported standard supervisor extension",
+		m_arch, subset);
+      return;
+    }
+  else if (subset[0] == 'x' && !standard_extensions_p (subset))
+    {
+      error_at (m_loc,
+		"%<-march=%s%>: extension %qs start with `x` but is "
+		"unsupported non-standard extension",
+		m_arch, subset);
+      return;
+    }
 
   riscv_subset_t *s = new riscv_subset_t ();
   riscv_subset_t *itr;
@@ -919,22 +965,16 @@ riscv_subset_list::parse_std_ext (const char *p)
       while (*std_exts && std_ext != *std_exts)
 	std_exts++;
 
-      if (std_ext != *std_exts)
-	{
-	  if (strchr (all_std_exts, std_ext) == NULL)
-	    error_at (m_loc, "%<-march=%s%>: unsupported ISA subset %<%c%>",
-		      m_arch, *p);
-	  else
-	    error_at (m_loc,
-		      "%<-march=%s%>: ISA string is not in canonical order. "
-		      "%<%c%>", m_arch, *p);
-	  return NULL;
-	}
+      subset[0] = std_ext;
+      if (std_ext != *std_exts && standard_extensions_p (subset))
+	error_at (m_loc,
+		  "%<-march=%s%>: ISA string is not in canonical order. "
+		  "%<%c%>",
+		  m_arch, *p);
 
       std_exts++;
 
       p++;
-      subset[0] = std_ext;
 
       p = parsing_subset_version (subset, p, &major_version, &minor_version,
 				  /* std_ext_p= */ true, &explicit_version_p);
@@ -1139,6 +1179,9 @@ riscv_subset_list::parse_multiletter_ext (const char *p,
 riscv_subset_list *
 riscv_subset_list::parse (const char *arch, location_t loc)
 {
+  if (riscv_subset_list::parse_failed)
+    return NULL;
+
   riscv_subset_list *subset_list = new riscv_subset_list (arch, loc);
   riscv_subset_t *itr;
   const char *p = arch;
@@ -1205,6 +1248,7 @@ riscv_subset_list::parse (const char *arch, location_t loc)
 
 fail:
   delete subset_list;
+  riscv_subset_list::parse_failed = true;
   return NULL;
 }
 
diff --git a/gcc/config/riscv/riscv-subset.h b/gcc/config/riscv/riscv-subset.h
index 92e4fb31692..6691997df7c 100644
--- a/gcc/config/riscv/riscv-subset.h
+++ b/gcc/config/riscv/riscv-subset.h
@@ -41,6 +41,11 @@ struct riscv_subset_t
 /* Subset list.  */
 class riscv_subset_list
 {
+public:
+  /* Because the parse method is called in several places, to prevent repeated
+     errors, use this flag to prevent it from repeating parse. */
+  static bool parse_failed;
+
 private:
   /* Original arch string.  */
   const char *m_arch;
diff --git a/gcc/testsuite/gcc.target/riscv/arch-2.c b/gcc/testsuite/gcc.target/riscv/arch-2.c
index 8908b4b3a8c..e308bf7407c 100644
--- a/gcc/testsuite/gcc.target/riscv/arch-2.c
+++ b/gcc/testsuite/gcc.target/riscv/arch-2.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=rv32ixabc_xfoo -mabi=ilp32" } */
+/* { dg-options "-march=rv32ixtheadba_xtheadsync -mabi=ilp32" } */
 int foo()
 {
 }
diff --git a/gcc/testsuite/gcc.target/riscv/arch-22.cc b/gcc/testsuite/gcc.target/riscv/arch-22.cc
new file mode 100644
index 00000000000..68337a70406
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/arch-22.cc
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gvcw_zvl128_s123_x123 -mabi=lp64d" } */
+int foo()
+{
+}
+
+/* { dg-error "ISA string is not in canonical order. 'c'" "" { target *-*-* } 0 } */
+/* { dg-error "extension 'w' is unsupported standard single letter extension" "" { target *-*-* } 0 } */
+/* { dg-error "extension 'zvl128' start with `z` but is unsupported standard extension" "" { target *-*-* } 0 } */
+/* { dg-error "extension 's123' start with `s` but is unsupported standard supervisor extension" "" { target *-*-* } 0 } */
+/* { dg-error "extension 'x123' start with `x` but is unsupported non-standard extension" "" { target *-*-* } 0 } */
diff --git a/gcc/testsuite/gcc.target/riscv/arch-3.c b/gcc/testsuite/gcc.target/riscv/arch-3.c
index 7aa945eca20..ac733746fd6 100644
--- a/gcc/testsuite/gcc.target/riscv/arch-3.c
+++ b/gcc/testsuite/gcc.target/riscv/arch-3.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=rv32isabc_xbar -mabi=ilp32" } */
+/* { dg-options "-march=rv32isvinval_xtheadba -mabi=ilp32" } */
 int foo()
 {
 }
diff --git a/gcc/testsuite/gcc.target/riscv/arch-5.c b/gcc/testsuite/gcc.target/riscv/arch-5.c
index 8258552214f..b8b6cd048f7 100644
--- a/gcc/testsuite/gcc.target/riscv/arch-5.c
+++ b/gcc/testsuite/gcc.target/riscv/arch-5.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=rv32i_zfoo_sabc_xbar -mabi=ilp32" } */
+/* { dg-options "-march=rv32i_zmmul_svnapot_xtheadba -mabi=ilp32" } */
 int foo()
 {
 }
diff --git a/gcc/testsuite/gcc.target/riscv/arch-8.c b/gcc/testsuite/gcc.target/riscv/arch-8.c
index 1b9e51b0e12..ef557aeb673 100644
--- a/gcc/testsuite/gcc.target/riscv/arch-8.c
+++ b/gcc/testsuite/gcc.target/riscv/arch-8.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=rv32id_zicsr_zifence -mabi=ilp32" } */
+/* { dg-options "-march=rv32id_zicsr_zifencei -mabi=ilp32" } */
 int foo()
 {
 }
diff --git a/gcc/testsuite/gcc.target/riscv/attribute-10.c b/gcc/testsuite/gcc.target/riscv/attribute-10.c
index 1e121a10753..868adef6ab7 100644
--- a/gcc/testsuite/gcc.target/riscv/attribute-10.c
+++ b/gcc/testsuite/gcc.target/riscv/attribute-10.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-march=rv32i -march=rv32im_sx_unexpectedstring -mabi=ilp32" } */
+/* { dg-options "-march=rv32i -march=rv32im_svnapot_unexpectedstring -mabi=ilp32" } */
 int foo()
 {
 }
diff --git a/gcc/testsuite/gcc.target/riscv/attribute-18.c b/gcc/testsuite/gcc.target/riscv/attribute-18.c
index 492360cf7c1..fddbf15fc3e 100644
--- a/gcc/testsuite/gcc.target/riscv/attribute-18.c
+++ b/gcc/testsuite/gcc.target/riscv/attribute-18.c
@@ -1,4 +1,4 @@
 /* { dg-do compile } */
-/* { dg-options "-mriscv-attribute -march=rv64imafdcp -mabi=lp64d -misa-spec=2.2" } */
+/* { dg-options "-mriscv-attribute -march=rv64imafdc -mabi=lp64d -misa-spec=2.2" } */
 int foo() {}
-/* { dg-final { scan-assembler ".attribute arch, \"rv64i2p0_m2p0_a2p0_f2p0_d2p0_c2p0_p\"" } } */
+/* { dg-final { scan-assembler ".attribute arch, \"rv64i2p0_m2p0_a2p0_f2p0_d2p0_c2p0\"" } } */
diff --git a/gcc/testsuite/gcc.target/riscv/attribute-19.c b/gcc/testsuite/gcc.target/riscv/attribute-19.c
index 562f8089361..8150452f5b1 100644
--- a/gcc/testsuite/gcc.target/riscv/attribute-19.c
+++ b/gcc/testsuite/gcc.target/riscv/attribute-19.c
@@ -1,4 +1,4 @@
 /* { dg-do compile } */
-/* { dg-options "-mriscv-attribute -march=rv64imp0p9 -mabi=lp64 -misa-spec=2.2" } */
+/* { dg-options "-mriscv-attribute -march=rv64im -mabi=lp64 -misa-spec=2.2" } */
 int foo() {}
-/* { dg-final { scan-assembler ".attribute arch, \"rv64i2p0_m2p0_p0p9\"" } } */
+/* { dg-final { scan-assembler ".attribute arch, \"rv64i2p0_m2p0\"" } } */
diff --git a/gcc/testsuite/gcc.target/riscv/attribute-8.c b/gcc/testsuite/gcc.target/riscv/attribute-8.c
index 4c91b9e6369..2065f74b977 100644
--- a/gcc/testsuite/gcc.target/riscv/attribute-8.c
+++ b/gcc/testsuite/gcc.target/riscv/attribute-8.c
@@ -1,6 +1,6 @@
 /* { dg-do compile } */
-/* { dg-options "-mriscv-attribute -march=rv32i2p0xabc_xv5 -mabi=ilp32" } */
+/* { dg-options "-mriscv-attribute -march=rv32i2p0xtheadba_xtheadbb -mabi=ilp32" } */
 int foo()
 {
 }
-/* { dg-final { scan-assembler ".attribute arch, \"rv32i2p0_xabc_xv5p0\"" } } */
+/* { dg-final { scan-assembler ".attribute arch, \"rv32i2p0_xtheadba1p0_xtheadbb1p0\"" } } */
diff --git a/gcc/testsuite/gcc.target/riscv/attribute-9.c b/gcc/testsuite/gcc.target/riscv/attribute-9.c
index 7e3741a827c..3c31848ed80 100644
--- a/gcc/testsuite/gcc.target/riscv/attribute-9.c
+++ b/gcc/testsuite/gcc.target/riscv/attribute-9.c
@@ -1,6 +1,6 @@
 /* { dg-do compile } */
-/* { dg-options "-mriscv-attribute -march=rv32i2p0sabc_xbar -mabi=ilp32e" } */
+/* { dg-options "-mriscv-attribute -march=rv32i2p0svinval_xtheadba -mabi=ilp32e" } */
 int foo()
 {
 }
-/* { dg-final { scan-assembler ".attribute arch, \"rv32i2p0_sabc_xbar\"" } } */
+/* { dg-final { scan-assembler ".attribute arch, \"rv32i2p0_svinval1p0_xtheadba1p0\"" } } */
diff --git a/gcc/testsuite/gcc.target/riscv/pr102957.c b/gcc/testsuite/gcc.target/riscv/pr102957.c
index 9747dde3038..322d49c62d4 100644
--- a/gcc/testsuite/gcc.target/riscv/pr102957.c
+++ b/gcc/testsuite/gcc.target/riscv/pr102957.c
@@ -3,3 +3,5 @@
 int foo()
 {
 }
+
+/* { dg-error "extension 'zb' starts with `z` but is unsupported standard extension" "" { target *-*-* } 0 } */
