diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 4f8902e37bd3b..938de5859513f 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -765,7 +765,7 @@ def err_builtin_redeclare : Error<"cannot redeclare builtin function %0">;
 def err_arm_invalid_specialreg : Error<"invalid special register for builtin">;
 def err_arm_invalid_coproc : Error<"coprocessor %0 must be configured as "
   "%select{GCP|CDE}1">;
-def err_invalid_cpu_supports : Error<"invalid cpu feature string for builtin">;
+def warn_invalid_cpu_supports : Warning<"invalid cpu feature string for builtin">;
 def err_invalid_cpu_is : Error<"invalid cpu name for builtin">;
 def err_invalid_cpu_specific_dispatch_value : Error<
 "invalid option '%0' for %select{cpu_specific|cpu_dispatch}1">;
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index 98684448f4ff5..e90014261217b 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -13952,6 +13952,8 @@ Value *CodeGenFunction::EmitX86CpuIs(StringRef CPUStr) {
 Value *CodeGenFunction::EmitX86CpuSupports(const CallExpr *E) {
   const Expr *FeatureExpr = E->getArg(0)->IgnoreParenCasts();
   StringRef FeatureStr = cast<StringLiteral>(FeatureExpr)->getString();
+  if (!getContext().getTargetInfo().validateCpuSupports(FeatureStr))
+    return Builder.getFalse();
   return EmitX86CpuSupports(FeatureStr);
 }
 
@@ -14041,6 +14043,8 @@ Value *CodeGenFunction::EmitAArch64CpuSupports(const CallExpr *E) {
   ArgStr.split(Features, "+");
   for (auto &Feature : Features) {
     Feature = Feature.trim();
+    if (!llvm::AArch64::parseArchExtension(Feature))
+      return Builder.getFalse();
     if (Feature != "default")
       Features.push_back(Feature);
   }
@@ -16639,7 +16643,8 @@ Value *CodeGenFunction::EmitPPCBuiltinExpr(unsigned BuiltinID,
   .Case(Name, {FA_WORD, Bitmask})
 #include "llvm/TargetParser/PPCTargetParser.def"
             .Default({0, 0});
-    assert(BitMask && "Invalid target feature string. Missed by SemaChecking?");
+    if (!BitMask)
+      return Builder.getFalse();
     Value *Op0 = llvm::ConstantInt::get(Int32Ty, FeatureWord);
     llvm::Function *F = CGM.getIntrinsic(Intrinsic::ppc_fixed_addr_ld);
     Value *TheCall = Builder.CreateCall(F, {Op0}, "cpu_supports");
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 690bdaa63d058..7be2b31df2413 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -2180,9 +2180,11 @@ static bool SemaBuiltinCpu(Sema &S, const TargetInfo &TI, CallExpr *TheCall,
 
   // Check the contents of the string.
   StringRef Feature = cast<StringLiteral>(Arg)->getString();
-  if (IsCPUSupports && !TheTI->validateCpuSupports(Feature))
-    return S.Diag(TheCall->getBeginLoc(), diag::err_invalid_cpu_supports)
-           << Arg->getSourceRange();
+  if (IsCPUSupports && !TheTI->validateCpuSupports(Feature)) {
+    S.Diag(TheCall->getBeginLoc(), diag::warn_invalid_cpu_supports)
+        << Arg->getSourceRange();
+    return false;
+  }
   if (!IsCPUSupports && !TheTI->validateCpuIs(Feature))
     return S.Diag(TheCall->getBeginLoc(), diag::err_invalid_cpu_is)
            << Arg->getSourceRange();
diff --git a/clang/test/CodeGen/aarch64-cpu-supports.c b/clang/test/CodeGen/aarch64-cpu-supports.c
index 872fec6827ef1..c54b7475a3fd5 100644
--- a/clang/test/CodeGen/aarch64-cpu-supports.c
+++ b/clang/test/CodeGen/aarch64-cpu-supports.c
@@ -34,6 +34,11 @@
 // CHECK-NEXT:    store i32 3, ptr [[RETVAL]], align 4
 // CHECK-NEXT:    br label [[RETURN]]
 // CHECK:       if.end4:
+// CHECK-NEXT:    br i1 false, label [[IF_THEN5:%.*]], label [[IF_END6:%.*]]
+// CHECK:       if.then5:
+// CHECK-NEXT:    store i32 4, ptr [[RETVAL]], align 4
+// CHECK-NEXT:    br label [[RETURN]]
+// CHECK:       if.end6:
 // CHECK-NEXT:    store i32 0, ptr [[RETVAL]], align 4
 // CHECK-NEXT:    br label [[RETURN]]
 // CHECK:       return:
@@ -50,5 +55,8 @@ int main(void) {
   if (__builtin_cpu_supports("sme2+ls64_v+wfxt"))
     return 3;
 
+  if (__builtin_cpu_supports("avx2"))
+    return 4;
+
   return 0;
 }
diff --git a/clang/test/Misc/warning-flags.c b/clang/test/Misc/warning-flags.c
index 9d4cac9e39b42..bb3c7d816d2f0 100644
--- a/clang/test/Misc/warning-flags.c
+++ b/clang/test/Misc/warning-flags.c
@@ -18,7 +18,7 @@ This test serves two purposes:
 
 The list of warnings below should NEVER grow.  It should gradually shrink to 0.
 
-CHECK: Warnings without flags (66):
+CHECK: Warnings without flags (67):
 
 CHECK-NEXT:   ext_expected_semi_decl_list
 CHECK-NEXT:   ext_explicit_specialization_storage_class
@@ -58,6 +58,7 @@ CHECK-NEXT:   warn_ignoring_ftabstop_value
 CHECK-NEXT:   warn_implements_nscopying
 CHECK-NEXT:   warn_incompatible_qualified_id
 CHECK-NEXT:   warn_invalid_asm_cast_lvalue
+CHECK-NEXT:   warn_invalid_cpu_supports
 CHECK-NEXT:   warn_maynot_respond
 CHECK-NEXT:   warn_method_param_redefinition
 CHECK-NEXT:   warn_missing_case_for_condition
diff --git a/clang/test/Sema/aarch64-cpu-supports.c b/clang/test/Sema/aarch64-cpu-supports.c
index 24aae9542dbc4..ddeed7c5bc9e9 100644
--- a/clang/test/Sema/aarch64-cpu-supports.c
+++ b/clang/test/Sema/aarch64-cpu-supports.c
@@ -5,19 +5,19 @@ int test_aarch64_features(void) {
   // expected-error@+1 {{expression is not a string literal}}
   if (__builtin_cpu_supports(ssbs2))
     return 1;
-  // expected-error@+1 {{invalid cpu feature string}}
+  // expected-warning@+1 {{invalid cpu feature string}}
   if (__builtin_cpu_supports(""))
     return 2;
-  // expected-error@+1 {{invalid cpu feature string}}
+  // expected-warning@+1 {{invalid cpu feature string}}
   if (__builtin_cpu_supports("pmull128"))
     return 3;
-  // expected-error@+1 {{invalid cpu feature string}}
+  // expected-warning@+1 {{invalid cpu feature string}}
   if (__builtin_cpu_supports("sve2,rpres"))
     return 4;
-  // expected-error@+1 {{invalid cpu feature string}}
+  // expected-warning@+1 {{invalid cpu feature string}}
   if (__builtin_cpu_supports("dgh+sve2-pmull"))
     return 5;
-  // expected-error@+1 {{invalid cpu feature string}}
+  // expected-warning@+1 {{invalid cpu feature string}}
   if (__builtin_cpu_supports("default"))
     return 6;
   if (__builtin_cpu_supports(" ssbs + bti "))
diff --git a/clang/test/Sema/builtin-cpu-supports.c b/clang/test/Sema/builtin-cpu-supports.c
index 733d797f3ff8f..51ee9661807f8 100644
--- a/clang/test/Sema/builtin-cpu-supports.c
+++ b/clang/test/Sema/builtin-cpu-supports.c
@@ -7,7 +7,7 @@ extern const char *str;
 
 int main(void) {
 #ifdef __x86_64__
-  if (__builtin_cpu_supports("ss")) // expected-error {{invalid cpu feature string}}
+  if (__builtin_cpu_supports("ss")) // expected-warning {{invalid cpu feature string}}
     a("sse4.2");
 
   if (__builtin_cpu_supports(str)) // expected-error {{expression is not a string literal}}
@@ -25,9 +25,9 @@ int main(void) {
   (void)__builtin_cpu_supports("x86-64-v2");
   (void)__builtin_cpu_supports("x86-64-v3");
   (void)__builtin_cpu_supports("x86-64-v4");
-  (void)__builtin_cpu_supports("x86-64-v5"); // expected-error {{invalid cpu feature string for builtin}}
+  (void)__builtin_cpu_supports("x86-64-v5"); // expected-warning {{invalid cpu feature string for builtin}}
 #else
-  if (__builtin_cpu_supports("neon")) // expected-error {{invalid cpu feature string for builtin}}
+  if (__builtin_cpu_supports("neon")) // expected-warning {{invalid cpu feature string for builtin}}
     a("vsx");
 
   if (__builtin_cpu_is("cortex-x3")) // expected-error {{builtin is not supported on this target}}