Re: [PATCH] Fix extract_muldiv (PR tree-optimization/56899)

2013-04-10 Thread Jeff Law
On 04/10/2013 09:31 AM, Jakub Jelinek wrote: Hi! As f1 in the testcase shows, applying distributive law in extract_muldiv_1 isn't safe if overflow behavior isn't defined, if we have (op0 + c1) * c2 and the type is signed, we can't just try to fold that to op0 * c2 + (c1 * c2) even when we know t

[PATCH] Fix extract_muldiv (PR tree-optimization/56899)

2013-04-10 Thread Jakub Jelinek
Hi! As f1 in the testcase shows, applying distributive law in extract_muldiv_1 isn't safe if overflow behavior isn't defined, if we have (op0 + c1) * c2 and the type is signed, we can't just try to fold that to op0 * c2 + (c1 * c2) even when we know that c1*c2 doesn't overflow, because op0 * c2 mi