commit 64cd5d3e3333948b551bd8c08f225dfbc86a8919
Author: Brian Paul <brianp@vmware.com>
Date:   Tue Sep 4 10:02:20 2012 -0600

    mesa: fix DIFFERENT_SIGNS() function
    
    Looks like converting this to a macro, returning bool, caused us to
    lose the high (31st) bit result.  Fixes piglit fbo-1d test.  Strange
    that none of the other tests I ran caught this.
    
    Fixes https://bugs.freedesktop.org/show_bug.cgi?id=54365

diff --git a/src/mesa/main/macros.h b/src/mesa/main/macros.h
index fc6f2a2..04d59d7 100644
--- a/src/mesa/main/macros.h
+++ b/src/mesa/main/macros.h
@@ -711,7 +711,7 @@ DIFFERENT_SIGNS(GLfloat x, GLfloat y)
    fi_type xfi, yfi;
    xfi.f = x;
    yfi.f = y;
-   return (xfi.i ^ yfi.i) & (1u << 31);
+   return !!((xfi.i ^ yfi.i) & (1u << 31));
 #else
    /* Could just use (x*y<0) except for the flatshading requirements.
     * Maybe there's a better way?