[Pixman] [PATCH 08/13] pixman-combine32.c: Fix bugs related to integer promotion

[Søren Sandmann]

From: Søren Sandmann Pedersen <ssp at redhat.com>

In the component alpha part of the PDF_SEPARABLE_BLEND_MODE macro, the
expression ~RED_8 (m) is used. Because RED_8(m) gets promoted to int
before ~ is applied, the whole expression typically becomes some
negative value rather than (255 - RED_8(m)) as desired.

Fix this by using unsigned temporary variables.

This reduces the number of failures in pixel-test to 363.
---
 pixman/pixman-combine32.c | 11 ++++++++---
 test/blitters-test.c      |  2 +-
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/pixman/pixman-combine32.c b/pixman/pixman-combine32.c
index 977c057..01c2523 100644
--- a/pixman/pixman-combine32.c
+++ b/pixman/pixman-combine32.c
@@ -640,13 +640,18 @@ combine_multiply_ca (pixman_implementation_t *imp,
 	    uint8_t da = ALPHA_8 (d);					\
 	    uint8_t ida = ~da;						\
 	    int32_t ra, rr, rg, rb;					\
+	    uint8_t ira, iga, iba;					\
 	    								\
 	    combine_mask_ca (&s, &m);					\
 	    								\
+	    ira = ~RED_8 (m);						\
+	    iga = ~GREEN_8 (m);						\
+	    iba = ~BLUE_8 (m);						\
+									\
 	    ra = da * 0xff + ALPHA_8 (s) * 0xff - ALPHA_8 (s) * da;	\
-	    rr = (~RED_8 (m)) * RED_8 (d) + ida * RED_8 (s);		\
-	    rg = (~GREEN_8 (m)) * GREEN_8 (d) + ida * GREEN_8 (s);	\
-	    rb = (~BLUE_8 (m)) * BLUE_8 (d) + ida * BLUE_8 (s);		\
+	    rr = ira * RED_8 (d) + ida * RED_8 (s);			\
+	    rg = iga * GREEN_8 (d) + ida * GREEN_8 (s);			\
+	    rb = iba * BLUE_8 (d) + ida * BLUE_8 (s);			\
 									\
 	    rr += blend_ ## name (RED_8 (d), da, RED_8 (s), RED_8 (m));	\
 	    rg += blend_ ## name (GREEN_8 (d), da, GREEN_8 (s), GREEN_8 (m)); \
diff --git a/test/blitters-test.c b/test/blitters-test.c
index ac8901f..e2a2e7f 100644
--- a/test/blitters-test.c
+++ b/test/blitters-test.c
@@ -394,6 +394,6 @@ main (int argc, const char *argv[])
     }
 
     return fuzzer_test_main("blitters", 2000000,
-			    0x613BBD64,
+			    0xB1D1F40E,
 			    test_composite, argc, argv);
 }
-- 
1.8.3.1