diff --git a/libavutil/cpu.c b/libavutil/cpu.c
index a1d1547033..85bc2d6499 100644
--- a/libavutil/cpu.c
+++ b/libavutil/cpu.c
@@ -23,6 +23,24 @@
 static int flags, checked;
 
 void av_force_cpu_flags(int arg){
+    if (   (arg & ( AV_CPU_FLAG_3DNOW    |
+                    AV_CPU_FLAG_3DNOWEXT |
+                    AV_CPU_FLAG_SSE      |
+                    AV_CPU_FLAG_SSE2     |
+                    AV_CPU_FLAG_SSE2SLOW |
+                    AV_CPU_FLAG_SSE3     |
+                    AV_CPU_FLAG_SSE3SLOW |
+                    AV_CPU_FLAG_SSSE3    |
+                    AV_CPU_FLAG_SSE4     |
+                    AV_CPU_FLAG_SSE42    |
+                    AV_CPU_FLAG_AVX      |
+                    AV_CPU_FLAG_XOP      |
+                    AV_CPU_FLAG_FMA4     ))
+        && !(arg & AV_CPU_FLAG_MMX)) {
+        av_log(NULL, AV_LOG_WARNING, "MMX implied by specified flags\n");
+        arg |= AV_CPU_FLAG_MMX;
+    }
+
     flags   = arg;
     checked = arg != -1;
 }