Hi experts, I have a small test case, it got different result when compile
with -O0 option and -O2 option. Is this a bug of gcc
?===============================test.c===============================#include
<stdio.h>void test(double a){ double b; b = a * 100000.00000000000; if(a<0)
printf("a<0\n"); else if(b == 19753086420000.0000000000) { a +=
0.000005; printf("a+=0.000005\n"); } printf("a=%f\n",a);}int main(){
double a=987654321/5.0;
test(a);}===========================================================result:=============================$
gcc -O0 test.c$ ./a.outa+=0.000005a=197530864.200005$ gcc -O2 test.c$
./a.outa=197530864.200000==========================================================
my gcc version:
=============================
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info
--enable-shared --enable-threads=posix --disable-checking --with-system-zlib
--enable-__cxa_atexit --disable-libunwind-exceptions --enable-java-awt=gtk
--host=i386-redhat-linux
Thread model: posix
gcc version 3.4.6 20060404
=============================
Regards,Jianhao Mo
_________________________________________________________________
MSN圣诞礼物火热登场，免费发放中，快来领取吧！
http://im.live.cn/emoticons/?ID=18
_______________________________________________
help-gplusplus mailing list
help-gplusplus@gnu.org
http://lists.gnu.org/mailman/listinfo/help-gplusplus
