Ian Lance Taylor <[EMAIL PROTECTED]> writes: | Gabriel Dos Reis <[EMAIL PROTECTED]> writes: | | > for this specific function (vrp_int_const_binop), I'm issuing a | > warning inside the else-if branch that tests for the overflowed | > result. I'm unclear why that is a false positive since the result is | > known to overflow. Could you elaborate? | | Within VRP, calculations are made on ranges. The upper and lower | limits of those ranges need not actually appear in the program. If | you warn whenever vrp_int_const_binop produces an overflow, you will | get an enormous number of false positives.
Thanks for this explanation. | I have a patch which issues warnings whenever gcc assumes that signed | overflow is undefined, except in loop IV calculations. I'm tweaking | it to see whether it is possible to bootstrap gcc with this patch. It | currently builds libcpp with no warnings, but falls over on this code | in decDivideOp in decNumber.c in libdecnumber: OK, I see; since today is a bit special I may not be able to get back to you as quickly as I would like. -- Gaby
