diff --git a/clang/lib/Lex/LiteralSupport.cpp b/clang/lib/Lex/LiteralSupport.cpp
index c1be3b2a97e5..e695b2ba3765 100644
--- a/clang/lib/Lex/LiteralSupport.cpp
+++ b/clang/lib/Lex/LiteralSupport.cpp
@@ -572,10 +572,12 @@ NumericLiteralParser::NumericLiteralParser(StringRef TokSpelling,
   checkSeparator(TokLoc, s, CSK_AfterDigits);
 
   // Initial scan to lookahead for fixed point suffix.
-  for (const char *c = s; c != ThisTokEnd; ++c) {
-    if (*c == 'r' || *c == 'k' || *c == 'R' || *c == 'K') {
-      saw_fixed_point_suffix = true;
-      break;
+  if (PP.getLangOpts().FixedPoint) {
+    for (const char *c = s; c != ThisTokEnd; ++c) {
+      if (*c == 'r' || *c == 'k' || *c == 'R' || *c == 'K') {
+        saw_fixed_point_suffix = true;
+        break;
+      }
     }
   }
 
@@ -589,12 +591,16 @@ NumericLiteralParser::NumericLiteralParser(StringRef TokSpelling,
     switch (*s) {
     case 'R':
     case 'r':
+      if (!PP.getLangOpts().FixedPoint) break;
       if (isFract || isAccum) break;
+      if (!(saw_period || saw_exponent)) break;
       isFract = true;
       continue;
     case 'K':
     case 'k':
+      if (!PP.getLangOpts().FixedPoint) break;
       if (isFract || isAccum) break;
+      if (!(saw_period || saw_exponent)) break;
       isAccum = true;
       continue;
     case 'h':      // FP Suffix for "half".
@@ -734,7 +740,6 @@ NumericLiteralParser::NumericLiteralParser(StringRef TokSpelling,
 
   if (!hadError && saw_fixed_point_suffix) {
     assert(isFract || isAccum);
-    //assert(radix == 16 || radix == 10);
   }
 }
 
diff --git a/clang/test/Frontend/fixed_point_errors.c b/clang/test/Frontend/fixed_point_errors.c
index f55fc82f917f..41427e343154 100644
--- a/clang/test/Frontend/fixed_point_errors.c
+++ b/clang/test/Frontend/fixed_point_errors.c
@@ -148,3 +148,87 @@ _Accum dec_with_hex_exp1 = 0.1p10k;    // expected-error{{invalid suffix 'p10k'
 _Accum dec_with_hex_exp2 = 0.1P10k;    // expected-error{{invalid suffix 'P10k' on integer constant}}
 _Accum hex_with_dex_exp1 = 0x0.1e10k;  // expected-error{{hexadecimal floating constant requires an exponent}}
 _Accum hex_with_dex_exp2 = 0x0.1E10k;  // expected-error{{hexadecimal floating constant requires an exponent}}
+
+void CheckSuffixOnIntegerLiterals() {
+  _Accum short_acc_int;
+  _Accum acc_int;
+  _Accum long_acc_int;
+
+  _Accum u_short_acc_int;
+  _Accum u_acc_int;
+  _Accum u_long_acc_int;
+
+  _Fract short_fract_int;
+  _Fract fract_int;
+  _Fract long_fract_int;
+
+  _Fract u_short_fract_int;
+  _Fract u_fract_int;
+  _Fract u_long_fract_int;
+
+  // Decimal integer literals (non-zero)
+  short_acc_int = 10hk; // expected-error{{invalid suffix 'hk' on integer constant}}
+  acc_int = 10k;        // expected-error{{invalid suffix 'k' on integer constant}}
+  long_acc_int = 10lk;  // expected-error{{invalid suffix 'lk' on integer constant}}
+
+  u_short_acc_int = 10uhk; // expected-error{{invalid suffix 'uhk' on integer constant}}
+  u_acc_int = 10uk;        // expected-error{{invalid suffix 'uk' on integer constant}}
+  u_long_acc_int = 10ulk;  // expected-error{{invalid suffix 'ulk' on integer constant}}
+
+  short_fract_int = 10hr; // expected-error{{invalid suffix 'hr' on integer constant}}
+  fract_int = 10r;        // expected-error{{invalid suffix 'r' on integer constant}}
+  long_fract_int = 10lr;  // expected-error{{invalid suffix 'lr' on integer constant}}
+
+  u_short_fract_int = 10uhr; // expected-error{{invalid suffix 'uhr' on integer constant}}
+  u_fract_int = 10ur;        // expected-error{{invalid suffix 'ur' on integer constant}}
+  u_long_fract_int = 10ulr;  // expected-error{{invalid suffix 'ulr' on integer constant}}
+
+  // Decimal integer literals (0)
+  short_acc_int = 0hk; // expected-error{{invalid suffix 'hk' on integer constant}}
+  acc_int = 0k;        // expected-error{{invalid suffix 'k' on integer constant}}
+  long_acc_int = 0lk;  // expected-error{{invalid suffix 'lk' on integer constant}}
+
+  // Decimal integer literals (large number)
+  acc_int = 999999999999999999k;   // expected-error{{invalid suffix 'k' on integer constant}}
+  fract_int = 999999999999999999r; // expected-error{{invalid suffix 'r' on integer constant}}
+
+  // Octal integer literals
+  short_acc_int = 010hk; // expected-error{{invalid suffix 'hk' on integer constant}}
+  acc_int = 010k;        // expected-error{{invalid suffix 'k' on integer constant}}
+  long_acc_int = 010lk;  // expected-error{{invalid suffix 'lk' on integer constant}}
+
+  u_short_acc_int = 010uhk; // expected-error{{invalid suffix 'uhk' on integer constant}}
+  u_acc_int = 010uk;        // expected-error{{invalid suffix 'uk' on integer constant}}
+  u_long_acc_int = 010ulk;  // expected-error{{invalid suffix 'ulk' on integer constant}}
+
+  short_fract_int = 010hr; // expected-error{{invalid suffix 'hr' on integer constant}}
+  fract_int = 010r;        // expected-error{{invalid suffix 'r' on integer constant}}
+  long_fract_int = 010lr;  // expected-error{{invalid suffix 'lr' on integer constant}}
+
+  u_short_fract_int = 010uhr; // expected-error{{invalid suffix 'uhr' on integer constant}}
+  u_fract_int = 010ur;        // expected-error{{invalid suffix 'ur' on integer constant}}
+  u_long_fract_int = 010ulr;  // expected-error{{invalid suffix 'ulr' on integer constant}}
+
+  // Hexadecimal integer literals
+  short_acc_int = 0x10hk; // expected-error{{invalid suffix 'hk' on integer constant}}
+  acc_int = 0x10k;        // expected-error{{invalid suffix 'k' on integer constant}}
+  long_acc_int = 0x10lk;  // expected-error{{invalid suffix 'lk' on integer constant}}
+
+  u_short_acc_int = 0x10uhk; // expected-error{{invalid suffix 'uhk' on integer constant}}
+  u_acc_int = 0x10uk;        // expected-error{{invalid suffix 'uk' on integer constant}}
+  u_long_acc_int = 0x10ulk;  // expected-error{{invalid suffix 'ulk' on integer constant}}
+
+  short_fract_int = 0x10hr; // expected-error{{invalid suffix 'hr' on integer constant}}
+  fract_int = 0x10r;        // expected-error{{invalid suffix 'r' on integer constant}}
+  long_fract_int = 0x10lr;  // expected-error{{invalid suffix 'lr' on integer constant}}
+
+  u_short_fract_int = 0x10uhr; // expected-error{{invalid suffix 'uhr' on integer constant}}
+  u_fract_int = 0x10ur;        // expected-error{{invalid suffix 'ur' on integer constant}}
+  u_long_fract_int = 0x10ulr;  // expected-error{{invalid suffix 'ulr' on integer constant}}
+
+  // Using auto
+  auto auto_fract = 0r;  // expected-error{{invalid suffix 'r' on integer constant}}
+                         // expected-warning@-1{{type specifier missing, defaults to 'int'}}
+  auto auto_accum = 0k;  // expected-error{{invalid suffix 'k' on integer constant}}
+                         // expected-warning@-1{{type specifier missing, defaults to 'int'}}
+}
diff --git a/clang/test/Frontend/fixed_point_errors.cpp b/clang/test/Frontend/fixed_point_errors.cpp
index 37027b4ef05d..cdd90ceb7548 100644
--- a/clang/test/Frontend/fixed_point_errors.cpp
+++ b/clang/test/Frontend/fixed_point_errors.cpp
@@ -7,3 +7,8 @@ _Accum accum;                           // expected-error{{unknown type name '_A
 _Fract fract;                           // expected-error{{unknown type name '_Fract'}}
 _Sat _Accum sat_accum;                  // expected-error{{unknown type name '_Sat'}}
                                         // expected-error@-1{{expected ';' after top level declarator}}
+
+int accum_int = 10k;     // expected-error{{invalid suffix 'k' on integer constant}}
+int fract_int = 10r;     // expected-error{{invalid suffix 'r' on integer constant}}
+float accum_flt = 10.0k; // expected-error{{invalid suffix 'k' on floating constant}}
+float fract_flt = 10.0r; // expected-error{{invalid suffix 'r' on floating constant}}
diff --git a/clang/test/Frontend/fixed_point_not_enabled.c b/clang/test/Frontend/fixed_point_not_enabled.c
index e5c82f54b62f..e7522213f98d 100644
--- a/clang/test/Frontend/fixed_point_not_enabled.c
+++ b/clang/test/Frontend/fixed_point_not_enabled.c
@@ -13,3 +13,9 @@ short _Accum short_accum;             // expected-error{{compile with '-ffixed-p
 _Accum accum;                         // expected-error{{compile with '-ffixed-point' to enable fixed point types}}
                                       // expected-warning@-1{{type specifier missing, defaults to 'int'}}
 long _Accum long_accum;               // expected-error{{compile with '-ffixed-point' to enable fixed point types}}
+
+// Cannot use fixed point suffixes
+int accum_int = 10k;     // expected-error{{invalid suffix 'k' on integer constant}}
+int fract_int = 10r;     // expected-error{{invalid suffix 'r' on integer constant}}
+float accum_flt = 10.0k; // expected-error{{invalid suffix 'k' on floating constant}}
+float fract_flt = 10.0r; // expected-error{{invalid suffix 'r' on floating constant}}