On Sun, Jun 20, 2021 at 11:50 PM Richard Biener via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > On Sat, Jun 19, 2021 at 9:49 PM apinski--- via Gcc-patches > <gcc-patches@gcc.gnu.org> wrote: > > > > From: Andrew Pinski <apin...@marvell.com> > > > > Since match_simplify_replacement uses gimple_simplify, there is a new > > ssa name created sometimes and then we go and replace the phi edge with > > this new ssa name, the range information on the phi is lost. > > I don't have a testcase right now where we lose the range information > > though but it does show up when enhancing match.pd to handle > > some min/max patterns and g++.dg/warn/Wstringop-overflow-1.C starts > > to fail. > > > > OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions. > > > > gcc/ChangeLog: > > > > * tree-ssa-phiopt.c (match_simplify_replacement): Duplicate range > > info if we're the only things setting the target PHI. > > --- > > gcc/tree-ssa-phiopt.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c > > index 24cbce9955a..feb8ca8d0d1 100644 > > --- a/gcc/tree-ssa-phiopt.c > > +++ b/gcc/tree-ssa-phiopt.c > > @@ -894,6 +894,14 @@ match_simplify_replacement (basic_block cond_bb, > > basic_block middle_bb, > > gsi_move_before (&gsi1, &gsi); > > reset_flow_sensitive_info (gimple_assign_lhs (stmt_to_move)); > > } > > + /* Duplicate range info if we're the only things setting the target PHI. > > */ > > + tree phi_result = PHI_RESULT (phi); > > + if (!gimple_seq_empty_p (seq) > > + && EDGE_COUNT (gimple_bb (phi)->preds) == 2 > > + && !POINTER_TYPE_P (TREE_TYPE (phi_result)) > > Please use INTEGRAL_TYPE_P (...)
Yes, using INTEGRAL_TYPE_P makes more sense here. Note I copied exactly what was already done in minmax_replacement. > > > + && SSA_NAME_RANGE_INFO (phi_result) > > && !SSA_NAME_RANGE_INFO (result) > > ? Why conditional on !gimple_seq_empty_p (seq)? The way I understand it is if !gimple_seq_empty_p (seq) is true then the result will be a new SSA name and therefore !SSA_NAME_RANGE_INFO (result) will also be true > It looks like we could do this trick (actually in both directions, > wherever the range > info is missing?) in replace_phi_edge_with_variable instead? Let me look into doing that. Thanks, Andrew > > Thanks, > Richard. > > ) > > + duplicate_ssa_name_range_info (result, SSA_NAME_RANGE_TYPE > > (phi_result), > > + SSA_NAME_RANGE_INFO (phi_result)); > > if (seq) > > gsi_insert_seq_before (&gsi, seq, GSI_SAME_STMT); > > > > -- > > 2.27.0 > >
