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 (...) > + && SSA_NAME_RANGE_INFO (phi_result) && !SSA_NAME_RANGE_INFO (result) ? Why conditional on !gimple_seq_empty_p (seq)? 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? 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 >
