GCC Compiler Bug ---------------- Reference: http://boudicca.tux.org/hypermail/linux-kernel/2000week05/0983.html From: Johan Kullstam (kullstam@ne.mediaone.net) Date: Thu Jan 27 2000 - 18:00:28 EST Horst von Brand writes: > My question in this vein would be the -fno-strength-reduce. The gcc bug > that placed this in the kernel was in gcc-2.7.2, and was worked around in > 2.7.2.3 by just making this option unconditional. Both 2.2.15pre4 and > 2.3.41pre2 at least demand gcc-2.7.2.3 as minimal version. just when you thought it was safe to go into the water... strength-reduction is broken again in gcc-2.95.2 (aka the current release). i'm not sure about what versions actually do work. for fun, try this one out. cut and paste the program bug.c. $ gcc -O2 bug.c -o b0 $ gcc -O2 -fno-strength-reduce bug.c -o b1 run b1. notice it finish immediately. now run b0. notice how b0 never terminates (until you ^C it). -- bug.c ----------------------------------------- static void bug(int size, int tries) { int i; int num = 0; while (num < size) { for (i = 1; i < tries; i++) num++; } } int main() { bug(5, 10); return 0; } -- bug.c -----------------------------------------