diff --git a/jcdctmgr.c b/jcdctmgr.c
index 711f9dab..12f88725 100644
--- a/jcdctmgr.c
+++ b/jcdctmgr.c
@@ -182,7 +182,7 @@ compute_reciprocal (UINT16 divisor, DCTELEM * dtbl)
     /* fq will be one bit too large to fit in DCTELEM, so adjust */
     fq >>= 1;
     r--;
-  } else if (fr <= (divisor / 2)) { /* fractional part is < 0.5 */
+  } else if (fr <= (divisor / 2U)) { /* fractional part is < 0.5 */
     c++;
   } else { /* fractional part is > 0.5 */
     fq++;
diff --git a/simd/jsimd_arm.c b/simd/jsimd_arm.c
index 5a095f2a..af0c2c8a 100644
--- a/simd/jsimd_arm.c
+++ b/simd/jsimd_arm.c
@@ -104,7 +104,7 @@ init_simd (void)
   int bufsize = 1024; /* an initial guess for the line buffer size limit */
 #endif
 
-  if (simd_support != ~0)
+  if (simd_support != ~0U)
     return;
 
   simd_support = 0;
diff --git a/simd/jsimd_i386.c b/simd/jsimd_i386.c
index 120eb029..e96f5b8d 100644
--- a/simd/jsimd_i386.c
+++ b/simd/jsimd_i386.c
@@ -41,7 +41,7 @@ init_simd (void)
 {
   char *env = NULL;
 
-  if (simd_support != ~0)
+  if (simd_support != ~0U)
     return;
 
   simd_support = jpeg_simd_cpu_support();