simple_idct_template: Fix strict aliasing violation

This fixes fate-wmv8-intrax8 in certain configurations, e.g.
gcc 4.4.
Signed-off-by: Martin Storsjö <martin@martin.st>

libavcodec/simple_idct_template.c

@@ -91,7 +91,7 @@ static inline void FUNC(idctRowCondDC)(int16_t *row, int extra_shift)
 
 #if HAVE_FAST_64BIT
 #define ROW0_MASK (0xffffLL << 48 * HAVE_BIGENDIAN)
-    if (((((uint64_t *)row)[0] & ~ROW0_MASK) | ((uint64_t *)row)[1]) == 0) {
+    if (((AV_RN64A(row) & ~ROW0_MASK) | AV_RN64A(row+4)) == 0) {
         uint64_t temp;
         if (DC_SHIFT - extra_shift > 0) {
             temp = (row[0] * (1 << (DC_SHIFT - extra_shift))) & 0xffff;
@@ -100,14 +100,14 @@ static inline void FUNC(idctRowCondDC)(int16_t *row, int extra_shift)
         }
         temp += temp * (1 << 16);
         temp += temp * ((uint64_t) 1 << 32);
-        ((uint64_t *)row)[0] = temp;
-        ((uint64_t *)row)[1] = temp;
+        AV_WN64A(row, temp);
+        AV_WN64A(row + 4, temp);
         return;
     }
 #else
-    if (!(((uint32_t*)row)[1] |
-          ((uint32_t*)row)[2] |
-          ((uint32_t*)row)[3] |
+    if (!(AV_RN32A(row+2) |
+          AV_RN32A(row+4) |
+          AV_RN32A(row+6) |
           row[1])) {
         uint32_t temp;
         if (DC_SHIFT - extra_shift > 0) {
@@ -116,8 +116,10 @@ static inline void FUNC(idctRowCondDC)(int16_t *row, int extra_shift)
             temp = (row[0] >> (extra_shift - DC_SHIFT)) & 0xffff;
         }
         temp += temp * (1 << 16);
-        ((uint32_t*)row)[0]=((uint32_t*)row)[1] =
-            ((uint32_t*)row)[2]=((uint32_t*)row)[3] = temp;
+        AV_WN32A(row, temp);
+        AV_WN32A(row+2, temp);
+        AV_WN32A(row+4, temp);
+        AV_WN32A(row+6, temp);
         return;
     }
 #endif