Sean Chittenden <[EMAIL PROTECTED]> writes: > Is there a place where -fno-fast-math > could be used as a CC option if the CC is gcc?
configure is what I had in mind ;-). I can't think of any part of the code where we'd really want this sort of optimization enabled. > After looking through gcc, using -O and -ffast-math will create broken > code, but -O2 -ffast-math _should_ be okay. At least in the gcc shipped with Red Hat 7.2, it doesn't seem to matter: you get the wrong answer regardless of -O level. Here's the test case I used: [tgl@rh1 tgl]$ cat bug.c #include <stdio.h> double d18000 = 18000.0; main() { int d = d18000 / 3600; printf("18000.0 / 3600 = %d\n", d); return 0; } [tgl@rh1 tgl]$ gcc bug.c [tgl@rh1 tgl]$ ./a.out 18000.0 / 3600 = 5 -- right [tgl@rh1 tgl]$ gcc -O2 -ffast-math bug.c [tgl@rh1 tgl]$ ./a.out 18000.0 / 3600 = 4 -- wrong -- I get 4 if -ffast-math, -O doesn't affect it [tgl@rh1 tgl]$ gcc -v Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/2.96/specs gcc version 2.96 20000731 (Red Hat Linux 7.1 2.96-98) regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly