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Marcin Cieslak 775fb0f0f1 Don't break help with gcc -O2 ... libDtHelp is unable to read SDL help files with -ftree-store-ccp optimization which is enabled by -O2 on gcc 4.2.1. GifUtils.c and decompress.c didn't work properly with -ftree-store-ccp enabled. GifUtils.c was repaired by fixing those warnings: GifUtils.c: In function 'create_pixmap': GifUtils.c:1093: warning: return makes integer from pointer without a cast GifUtils.c:1110: warning: return makes integer from pointer without a cast GifUtils.c:1215: warning: return makes integer from pointer without a cast GifUtils.c: In function 'gif_to_pixmap': GifUtils.c:1242: warning: return makes integer from pointer without a cast decompress.c didn't generate warnings, but the only effect of the -ftree-store-cpp was to introduce this change: addq $1, %rax movq %rax, (%rbx) .L90: - cmpl $157, %edx + cmpl $-99, %edx jne .L86 movl 8(%rbx), %eax subl $1, %eax Which corresponds to this source code: bufioI.h 57 #define BufFileGet(f) ((f)->left-- ? *(f)->bufp++ : (*(f)->io) (f)) 42 int (*io)(/* BufFilePtr f */); decompress.c 53 #ifdef NO_UCHAR 54 typedef char char_type; 55 #else 56 typedef unsigned char char_type; 57 #endif /* UCHAR */ 58 59 static char_type magic_header[] = { "\037\235" }; /* 1F 9D */ 131 if ((BufFileGet(f) != (magic_header[0] & 0xFF)) || 132 (BufFileGet(f) != (magic_header[1] & 0xFF))) 133 { 134 return 0; 135 } BufFileGet() returns (int), so the (unsigned char) constants got promoted to (int) with sign extension; therefore constant 157 decimal (0x9D) became -99 decimal, sign extended (0xffffff9D), and the comparison was always false. Tested using: $ gcc -v Using built-in specs. Target: amd64-undermydesk-freebsd Configured with: FreeBSD/amd64 system compiler Thread model: posix gcc version 4.2.1 20070831 patched [FreeBSD] Running on: FreeBSD 10.0-CURRENT (r240948M) built Wed Sep 26 23:33:08 CEST 2012		2012-10-01 18:59:14 -06:00
cde	Don't break help with gcc -O2	2012-10-01 18:59:14 -06:00