------- Additional Comments From rth at gcc dot gnu dot org 2005-02-01 06:36 ------- Subject: Re: [4.0 Regression] A side effect is missed in 0 % a++.
On Mon, Jan 31, 2005 at 08:45:34PM -0700, Jeffrey A Law wrote: > + /* X % 0, return X % 0 unchanged so that we can get the > + proper warnings and errors. */ > if (integer_zerop (arg1)) > return t; > > + /* 0 % X is always zero, but be sure to preserve any side > + effects in X. Place this after checking for X == 0. */ > + if (integer_zerop (arg0)) > + return omit_one_operand (type, integer_zero_node, arg1); Not ok yet. You have to *know* that arg1 is not zero. Otherwise you're still potentially removing a division-by-zero. The only check you have at this level for this is integer_nonzerop. r~ -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19723
