diff --git a/clang/lib/Headers/emmintrin.h b/clang/lib/Headers/emmintrin.h
--- a/clang/lib/Headers/emmintrin.h
+++ b/clang/lib/Headers/emmintrin.h
@@ -4970,10 +4970,10 @@
 
 #define _MM_SHUFFLE2(x, y) (((x) << 1) | (y))
 
-#define _MM_DENORMALS_ZERO_ON   (0x0040)
-#define _MM_DENORMALS_ZERO_OFF  (0x0000)
+#define _MM_DENORMALS_ZERO_ON   (0x0040U)
+#define _MM_DENORMALS_ZERO_OFF  (0x0000U)
 
-#define _MM_DENORMALS_ZERO_MASK (0x0040)
+#define _MM_DENORMALS_ZERO_MASK (0x0040U)
 
 #define _MM_GET_DENORMALS_ZERO_MODE() (_mm_getcsr() & _MM_DENORMALS_ZERO_MASK)
 #define _MM_SET_DENORMALS_ZERO_MODE(x) (_mm_setcsr((_mm_getcsr() & ~_MM_DENORMALS_ZERO_MASK) | (x)))
diff --git a/clang/lib/Headers/xmmintrin.h b/clang/lib/Headers/xmmintrin.h
--- a/clang/lib/Headers/xmmintrin.h
+++ b/clang/lib/Headers/xmmintrin.h
@@ -2931,31 +2931,31 @@
 
 #define _MM_SHUFFLE(z, y, x, w) (((z) << 6) | ((y) << 4) | ((x) << 2) | (w))
 
-#define _MM_EXCEPT_INVALID    (0x0001)
-#define _MM_EXCEPT_DENORM     (0x0002)
-#define _MM_EXCEPT_DIV_ZERO   (0x0004)
-#define _MM_EXCEPT_OVERFLOW   (0x0008)
-#define _MM_EXCEPT_UNDERFLOW  (0x0010)
-#define _MM_EXCEPT_INEXACT    (0x0020)
-#define _MM_EXCEPT_MASK       (0x003f)
-
-#define _MM_MASK_INVALID      (0x0080)
-#define _MM_MASK_DENORM       (0x0100)
-#define _MM_MASK_DIV_ZERO     (0x0200)
-#define _MM_MASK_OVERFLOW     (0x0400)
-#define _MM_MASK_UNDERFLOW    (0x0800)
-#define _MM_MASK_INEXACT      (0x1000)
-#define _MM_MASK_MASK         (0x1f80)
-
-#define _MM_ROUND_NEAREST     (0x0000)
-#define _MM_ROUND_DOWN        (0x2000)
-#define _MM_ROUND_UP          (0x4000)
-#define _MM_ROUND_TOWARD_ZERO (0x6000)
-#define _MM_ROUND_MASK        (0x6000)
-
-#define _MM_FLUSH_ZERO_MASK   (0x8000)
-#define _MM_FLUSH_ZERO_ON     (0x8000)
-#define _MM_FLUSH_ZERO_OFF    (0x0000)
+#define _MM_EXCEPT_INVALID    (0x0001U)
+#define _MM_EXCEPT_DENORM     (0x0002U)
+#define _MM_EXCEPT_DIV_ZERO   (0x0004U)
+#define _MM_EXCEPT_OVERFLOW   (0x0008U)
+#define _MM_EXCEPT_UNDERFLOW  (0x0010U)
+#define _MM_EXCEPT_INEXACT    (0x0020U)
+#define _MM_EXCEPT_MASK       (0x003fU)
+
+#define _MM_MASK_INVALID      (0x0080U)
+#define _MM_MASK_DENORM       (0x0100U)
+#define _MM_MASK_DIV_ZERO     (0x0200U)
+#define _MM_MASK_OVERFLOW     (0x0400U)
+#define _MM_MASK_UNDERFLOW    (0x0800U)
+#define _MM_MASK_INEXACT      (0x1000U)
+#define _MM_MASK_MASK         (0x1f80U)
+
+#define _MM_ROUND_NEAREST     (0x0000U)
+#define _MM_ROUND_DOWN        (0x2000U)
+#define _MM_ROUND_UP          (0x4000U)
+#define _MM_ROUND_TOWARD_ZERO (0x6000U)
+#define _MM_ROUND_MASK        (0x6000U)
+
+#define _MM_FLUSH_ZERO_MASK   (0x8000U)
+#define _MM_FLUSH_ZERO_ON     (0x8000U)
+#define _MM_FLUSH_ZERO_OFF    (0x0000U)
 
 #define _MM_GET_EXCEPTION_MASK() (_mm_getcsr() & _MM_MASK_MASK)
 #define _MM_GET_EXCEPTION_STATE() (_mm_getcsr() & _MM_EXCEPT_MASK)
diff --git a/clang/test/Headers/x86-header-warnings.c b/clang/test/Headers/x86-header-warnings.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Headers/x86-header-warnings.c
@@ -0,0 +1,43 @@
+// Fix sign conversion warnings found by fsanitize=implicit-integer-sign-change
+// in intrinsic headers.
+// Preprocess file to workaround no warnings in system headers.
+// RUN: %clang_cc1 %s -triple x86_64-pc-linux-gnu -ffreestanding -E 2>&1 \
+// RUN:     | %clang_cc1 -x c - -triple x86_64-pc-linux-gnu -ffreestanding -Wsign-conversion -E -o - 2>&1 \
+// RUN:     | FileCheck --allow-empty %s
+// REQUIRES: x86-registered-target
+
+#include <x86intrin.h>
+
+void test0() {
+  // CHECK-LABEL: test0
+  // CHECK-NOT: warning:
+  _MM_SET_DENORMALS_ZERO_MODE(_MM_DENORMALS_ZERO_ON);
+  _MM_SET_DENORMALS_ZERO_MODE(_MM_DENORMALS_ZERO_OFF);
+  _MM_SET_DENORMALS_ZERO_MODE(_MM_DENORMALS_ZERO_MASK);
+
+  _MM_SET_EXCEPTION_STATE(_MM_EXCEPT_INVALID);
+  _MM_SET_EXCEPTION_STATE(_MM_EXCEPT_DENORM);
+  _MM_SET_EXCEPTION_STATE(_MM_EXCEPT_DIV_ZERO);
+  _MM_SET_EXCEPTION_STATE(_MM_EXCEPT_OVERFLOW);
+  _MM_SET_EXCEPTION_STATE(_MM_EXCEPT_UNDERFLOW);
+  _MM_SET_EXCEPTION_STATE(_MM_EXCEPT_INEXACT);
+  _MM_SET_EXCEPTION_STATE(_MM_EXCEPT_MASK);
+
+  _MM_SET_EXCEPTION_MASK(_MM_MASK_INVALID);
+  _MM_SET_EXCEPTION_MASK(_MM_MASK_DENORM);
+  _MM_SET_EXCEPTION_MASK(_MM_MASK_DIV_ZERO);
+  _MM_SET_EXCEPTION_MASK(_MM_MASK_OVERFLOW);
+  _MM_SET_EXCEPTION_MASK(_MM_MASK_UNDERFLOW);
+  _MM_SET_EXCEPTION_MASK(_MM_MASK_INEXACT);
+  _MM_SET_EXCEPTION_MASK(_MM_MASK_MASK);
+
+  _MM_SET_ROUNDING_MODE(_MM_ROUND_NEAREST);
+  _MM_SET_ROUNDING_MODE(_MM_ROUND_DOWN);
+  _MM_SET_ROUNDING_MODE(_MM_ROUND_UP);
+  _MM_SET_ROUNDING_MODE(_MM_ROUND_TOWARD_ZERO);
+  _MM_SET_ROUNDING_MODE(_MM_ROUND_MASK);
+
+  _MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_MASK);
+  _MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_ON);
+  _MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_OFF);
+}