diff --git a/clang/test/Driver/riscv-arch.c b/clang/test/Driver/riscv-arch.c
index abbe8612b3780..8c701a736fc7e 100644
--- a/clang/test/Driver/riscv-arch.c
+++ b/clang/test/Driver/riscv-arch.c
@@ -204,7 +204,7 @@
 // RUN: not %clang --target=riscv32-unknown-elf -march=unknown -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-STR %s
 // RV32-STR: error: invalid arch name 'unknown',
-// RV32-STR: string must begin with rv32{i,e,g} or rv64{i,e,g}
+// RV32-STR: string must begin with rv32{i,e,g}, rv64{i,e,g}, or a supported profile name
 
 // RUN: not %clang --target=riscv32-unknown-elf -march=rv32q -### %s \
 // RUN: -fsyntax-only 2>&1 | FileCheck -check-prefix=RV32-LETTER %s
diff --git a/clang/test/Driver/riscv-profiles.c b/clang/test/Driver/riscv-profiles.c
index 647567d4c971f..298f301de3feb 100644
--- a/clang/test/Driver/riscv-profiles.c
+++ b/clang/test/Driver/riscv-profiles.c
@@ -318,7 +318,7 @@
 // PROFILE-WITH-ADDITIONAL: "-target-feature" "+zkt"
 
 // RUN: not %clang --target=riscv64 -### -c %s 2>&1 -march=rva19u64_zfa | FileCheck -check-prefix=INVALID-PROFILE %s
-// INVALID-PROFILE: error: invalid arch name 'rva19u64_zfa', unsupported profile
+// INVALID-PROFILE: error: invalid arch name 'rva19u64_zfa', string must begin with rv32{i,e,g}, rv64{i,e,g}, or a supported profile name
 
 // RUN: not %clang --target=riscv64 -### -c %s 2>&1 -march=rva22u64zfa | FileCheck -check-prefix=INVALID-ADDITIONAL %s
 // INVALID-ADDITIONAL: error: invalid arch name 'rva22u64zfa', additional extensions must be after separator '_'
diff --git a/llvm/lib/TargetParser/RISCVISAInfo.cpp b/llvm/lib/TargetParser/RISCVISAInfo.cpp
index 3b0cf8fab25f4..d154c00a78592 100644
--- a/llvm/lib/TargetParser/RISCVISAInfo.cpp
+++ b/llvm/lib/TargetParser/RISCVISAInfo.cpp
@@ -592,40 +592,39 @@ RISCVISAInfo::parseArchString(StringRef Arch, bool EnableExperimentalExtension,
     return createStringError(errc::invalid_argument,
                              "string must be lowercase");
 
-  if (Arch.starts_with("rvi") || Arch.starts_with("rva") ||
-      Arch.starts_with("rvb") || Arch.starts_with("rvm")) {
+  // ISA string must begin with rv32, rv64, or a profile.
+  unsigned XLen = 0;
+  if (Arch.consume_front("rv32")) {
+    XLen = 32;
+  } else if (Arch.consume_front("rv64")) {
+    XLen = 64;
+  } else {
+    // Try parsing as a profile.
     const auto *FoundProfile =
         llvm::find_if(SupportedProfiles, [Arch](const RISCVProfile &Profile) {
           return Arch.starts_with(Profile.Name);
         });
 
-    if (FoundProfile == std::end(SupportedProfiles))
-      return createStringError(errc::invalid_argument, "unsupported profile");
-
-    std::string NewArch = FoundProfile->MArch.str();
-    StringRef ArchWithoutProfile = Arch.substr(FoundProfile->Name.size());
-    if (!ArchWithoutProfile.empty()) {
-      if (!ArchWithoutProfile.starts_with("_"))
-        return createStringError(
-            errc::invalid_argument,
-            "additional extensions must be after separator '_'");
-      NewArch += ArchWithoutProfile.str();
+    if (FoundProfile != std::end(SupportedProfiles)) {
+      std::string NewArch = FoundProfile->MArch.str();
+      StringRef ArchWithoutProfile = Arch.drop_front(FoundProfile->Name.size());
+      if (!ArchWithoutProfile.empty()) {
+        if (ArchWithoutProfile.front() != '_')
+          return createStringError(
+              errc::invalid_argument,
+              "additional extensions must be after separator '_'");
+        NewArch += ArchWithoutProfile.str();
+      }
+      return parseArchString(NewArch, EnableExperimentalExtension,
+                             ExperimentalExtensionVersionCheck, IgnoreUnknown);
     }
-    return parseArchString(NewArch, EnableExperimentalExtension,
-                           ExperimentalExtensionVersionCheck, IgnoreUnknown);
   }
 
-  // ISA string must begin with rv32 or rv64.
-  unsigned XLen = 0;
-  if (Arch.consume_front("rv32"))
-    XLen = 32;
-  else if (Arch.consume_front("rv64"))
-    XLen = 64;
-
   if (XLen == 0 || Arch.empty())
     return createStringError(
         errc::invalid_argument,
-        "string must begin with rv32{i,e,g} or rv64{i,e,g}");
+        "string must begin with rv32{i,e,g}, rv64{i,e,g}, or a supported "
+        "profile name");
 
   std::unique_ptr<RISCVISAInfo> ISAInfo(new RISCVISAInfo(XLen));
   MapVector<std::string, RISCVISAUtils::ExtensionVersion,
diff --git a/llvm/test/MC/RISCV/invalid-attribute.s b/llvm/test/MC/RISCV/invalid-attribute.s
index 1d732af83cda3..2989e80b269ae 100644
--- a/llvm/test/MC/RISCV/invalid-attribute.s
+++ b/llvm/test/MC/RISCV/invalid-attribute.s
@@ -11,7 +11,7 @@
 # CHECK: [[@LINE-1]]:12: error: attribute name not recognised: unknown
 
 .attribute arch, "foo"
-# CHECK: [[@LINE-1]]:18: error: invalid arch name 'foo', string must begin with rv32{i,e,g} or rv64{i,e,g}
+# CHECK: [[@LINE-1]]:18: error: invalid arch name 'foo', string must begin with rv32{i,e,g}, rv64{i,e,g}, or a supported profile name{{$}}
 
 .attribute arch, "rv32i2p1_y2p0"
 # CHECK: [[@LINE-1]]:18: error: invalid arch name 'rv32i2p1_y2p0', invalid standard user-level extension 'y'
diff --git a/llvm/unittests/TargetParser/RISCVISAInfoTest.cpp b/llvm/unittests/TargetParser/RISCVISAInfoTest.cpp
index 9f23000d733d0..3aa0178100abf 100644
--- a/llvm/unittests/TargetParser/RISCVISAInfoTest.cpp
+++ b/llvm/unittests/TargetParser/RISCVISAInfoTest.cpp
@@ -118,7 +118,8 @@ TEST(ParseArchString, RejectsUpperCase) {
 TEST(ParseArchString, RejectsInvalidBaseISA) {
   for (StringRef Input : {"rv32", "rv64", "rv65i"}) {
     EXPECT_EQ(toString(RISCVISAInfo::parseArchString(Input, true).takeError()),
-              "string must begin with rv32{i,e,g} or rv64{i,e,g}");
+              "string must begin with rv32{i,e,g}, rv64{i,e,g}, or a supported "
+              "profile name");
   }
 
   for (StringRef Input : {"rv32j", "rv32_i"}) {
@@ -133,7 +134,8 @@ TEST(ParseArchString, RejectsInvalidBaseISA) {
 TEST(ParseArchString, RejectsUnsupportedBaseISA) {
   for (StringRef Input : {"rv128i", "rv128g"}) {
     EXPECT_EQ(toString(RISCVISAInfo::parseArchString(Input, true).takeError()),
-              "string must begin with rv32{i,e,g} or rv64{i,e,g}");
+              "string must begin with rv32{i,e,g}, rv64{i,e,g}, or a supported "
+              "profile name");
   }
 }