------- Comment #6 from rguenther at suse dot de 2009-01-22 09:29 ------- Subject: Re: ICE in set_value_range, at tree-vrp.c:398
On Thu, 22 Jan 2009, bonzini at gnu dot org wrote: > ------- Comment #4 from bonzini at gnu dot org 2009-01-22 09:00 ------- > In PRE there is a fold_convert_const_int_from_int call simplifying "(signed > char) 249" to -7, but setting the TREE_OVERFLOW flag in the meanwhile. I > don't think it makes sense to set the overflow flag on a NOP: > > * `The result of, or the signal raised by, converting an integer to a > signed integer type when the value cannot be represented in an > object of that type (C90 6.2.1.2, C99 6.3.1.3).' > > For conversion to a type of width N, the value is reduced modulo > 2^N to be within range of the type; no signal is raised. > > (Integers implementation, from the gcc manual). Correct. PRE should make sure to clear TREE_OVERFLOW, like CCP for example does. A more general solution unfortunately opens too many cans of worms. Richard. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38932
