diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -11636,7 +11636,7 @@
 
 // RISC-V builtin required extension warning
 def err_riscv_builtin_requires_extension : Error<
-  "builtin requires at least one of the following extensions to be enabled: %0">;
+  "builtin requires%select{| at least one of the following extensions to be enabled}0: %1">;
 def err_riscv_builtin_invalid_lmul : Error<
   "LMUL argument must be in the range [0,3] or [5,7]">;
 
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -4369,13 +4369,20 @@
     if (llvm::none_of(ReqOpFeatures,
                       [&TI](StringRef OF) { return TI.hasFeature(OF); })) {
       std::string FeatureStrs;
+      bool IsExtension = true;
       for (StringRef OF : ReqOpFeatures) {
         // If the feature is 64bit, alter the string so it will print better in
         // the diagnostic.
-        if (OF == "64bit")
+        if (OF == "64bit") {
+          assert(ReqOpFeatures.size() == 1 && "Expected '64bit' to be alone");
           OF = "RV64";
-        if (OF == "32bit")
+          IsExtension = false;
+        }
+        if (OF == "32bit") {
+          assert(ReqOpFeatures.size() == 1 && "Expected '32bit' to be alone");
           OF = "RV32";
+          IsExtension = false;
+        }
 
         // Convert features like "zbr" and "experimental-zbr" to "Zbr".
         OF.consume_front("experimental-");
@@ -4390,6 +4397,7 @@
       // Error message
       FeatureMissing = true;
       Diag(TheCall->getBeginLoc(), diag::err_riscv_builtin_requires_extension)
+          << IsExtension
           << TheCall->getSourceRange() << StringRef(FeatureStrs);
     }
   }
diff --git a/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv32-zbb-error.c b/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv32-zbb-error.c
--- a/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv32-zbb-error.c
+++ b/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv32-zbb-error.c
@@ -2,5 +2,5 @@
 // RUN: %clang_cc1 -triple riscv32 -target-feature +zbb -verify %s -o -
 
 int orc_b_64(int a) {
-  return __builtin_riscv_orc_b_64(a); // expected-error {{builtin requires at least one of the following extensions to be enabled: 'RV64'}}
+  return __builtin_riscv_orc_b_64(a); // expected-error {{builtin requires: 'RV64'}}
 }
diff --git a/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv64-zbkb-error.c b/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv64-zbkb-error.c
--- a/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv64-zbkb-error.c
+++ b/clang/test/CodeGen/RISCV/rvb-intrinsics/riscv64-zbkb-error.c
@@ -3,10 +3,10 @@
 
 int zip(int rs1)
 {
-  return __builtin_riscv_zip_32(rs1); // expected-error {{builtin requires at least one of the following extensions to be enabled: 'RV32'}}
+  return __builtin_riscv_zip_32(rs1); // expected-error {{builtin requires: 'RV32'}}
 }
 
 int unzip(int rs1)
 {
-  return __builtin_riscv_unzip_32(rs1); // expected-error {{builtin requires at least one of the following extensions to be enabled: 'RV32'}}
+  return __builtin_riscv_unzip_32(rs1); // expected-error {{builtin requires: 'RV32'}}
 }