mmx: convert while (w) to if (w) when possible

gcc isn't able to see that w is no greater than 1, so it generates
unnecessary loop instructions with while (w).

Signed-off-by: Matt Turner <mattst88@gmail.com>

diff --git a/pixman/pixman-mmx.c b/pixman/pixman-mmx.c
index f835a14..c044593 100644 (file)
--- a/pixman/pixman-mmx.c
+++ b/pixman/pixman-mmx.c
@@ -1142,12 +1142,9 @@ mmx_composite_over_n_8888 (pixman_implementation_t *imp,
 
        CHECKPOINT ();
 
-       while (w)
+       if (w)
        {
            *dst = store8888 (over (vsrc, vsrca, load8888 (*dst)));
-
-           w--;
-           dst++;
        }
     }
 
@@ -1383,16 +1380,12 @@ mmx_composite_over_8888_n_8888 (pixman_implementation_t *imp,
            src += 2;
        }
 
-       while (w)
+       if (w)
        {
            __m64 s = load8888 (*src);
            __m64 d = load8888 (*dst);
 
            *dst = store8888 (in_over (s, expand_alpha (s), vmask, d));
-
-           w--;
-           dst++;
-           src++;
        }
     }
 
@@ -1758,7 +1751,7 @@ mmx_composite_over_n_8_8888 (pixman_implementation_t *imp,
 
        CHECKPOINT ();
 
-       while (w)
+       if (w)
        {
            uint64_t m = *mask;
 
@@ -1770,10 +1763,6 @@ mmx_composite_over_n_8_8888 (pixman_implementation_t *imp,
                    vsrc, vsrca, expand_alpha_rev (to_m64 (m)), vdest);
                *dst = store8888 (vdest);
            }
-
-           w--;
-           mask++;
-           dst++;
        }
     }
 
@@ -2026,7 +2015,7 @@ mmx_composite_src_n_8_8888 (pixman_implementation_t *imp,
 
        CHECKPOINT ();
 
-       while (w)
+       if (w)
        {
            uint64_t m = *mask;
 
@@ -2041,10 +2030,6 @@ mmx_composite_src_n_8_8888 (pixman_implementation_t *imp,
            {
                *dst = 0;
            }
-
-           w--;
-           mask++;
-           dst++;
        }
     }
 
@@ -2366,16 +2351,12 @@ mmx_composite_over_pixbuf_8888 (pixman_implementation_t *imp,
            src += 2;
        }
 
-       while (w)
+       if (w)
        {
            __m64 s = load8888 (*src);
            __m64 d = load8888 (*dst);
 
            *dst = store8888 (over_rev_non_pre (s, d));
-
-           w--;
-           dst++;
-           src++;
        }
     }