Agreed. Thank you Martin! On Sat, Aug 25, 2018, 21:19 Jeff Law <l...@redhat.com> wrote:
> On 08/24/2018 10:50 AM, Aldy Hernandez wrote: > > As discussed in the PR, the MIN_EXPR being passed to VRP has > > incompatible signs. I expect MIN_EXPR to have the same type for all > > arguments plus the MIN_EXPR node itself, but this is not the case. > > > > The culprit on PPC is expand_builtin_strncmp, but fixing it there causes > > other problems on x86-64 (see PR). I believe Martin Sebor had some > > questions related to the x86 fallout > > (https://gcc.gnu.org/ml/gcc/2018-08/msg00164.html). > > > > Since it seems this has been broken for a while, and I'd like to unbreak > > PPC without having to take my patch out, I suggest (for now) just > > passing the sign of the first argument as VRP had been doing all along > > (through int_const_binop): > > > > int_const_binop(): > > ... > > tree type = TREE_TYPE (arg1); > > ... > > if (TREE_CODE (arg1) == INTEGER_CST && TREE_CODE (arg2) == INTEGER_CST) > > { > > wide_int warg1 = wi::to_wide (arg1), res; > > wide_int warg2 = wi::to_wide (arg2, TYPE_PRECISION (type)); > > success = wide_int_binop (res, code, warg1, warg2, sign, > &overflow); > > poly_res = res; > > } > > > > At some point later, if someone is sufficiently vexed by broken > > MIN_EXPR, we could fix it and the x86 fall out. > > > > OK pending tests? > I don't think we need this after fixing the strncmp code... > > Jeff > >
