On Sun, May 29, 2022 at 5:59 PM Di Zhao OS <diz...@os.amperecomputing.com> wrote: > > Hi, attached is a new version of the patch. The changes are: > - Skip using temporary equivalences for floating-point values, because > folding expressions can generate incorrect values. For example, > operations on 0.0 and -0.0 may have different results. > - Avoid inserting duplicated back-refs from value-number to predicates. > - Disable fre in testsuite/g++.dg/pr83541.C . > > Summary of the previous versions: > https://gcc.gnu.org/pipermail/gcc-patches/2021-December/587346.html > > Is the patch still considered?
Yes, sorry - I have to catch up after release work but will look again at this change after some vacation next week. Richard. > > Thanks, > Di Zhao > > --- > > Extend FRE with temporary equivalences. > > 2022-05-29 Di Zhao <diz...@os.amperecomputing.com> > > gcc/ChangeLog: > PR tree-optimization/101186 > * tree-ssa-sccvn.c (VN_INFO): remove assertions (there could be a > predicate already). > (dominated_by_p_w_unex): Moved upward. > (vn_nary_op_get_predicated_value): Moved upward. > (is_vn_valid_at_bb): Check if vn_pval is valid at BB. > (lookup_equiv_head): Lookup the "equivalence head" of given node. > (lookup_equiv_heads): Lookup the "equivalence head"s of given nodes. > (vn_tracking_edge): Extracted utility function. > (init_vn_nary_op_from_stmt): Insert and lookup by "equivalence head"s. > (vn_nary_op_insert_into): Insert new value at the front. > (vn_nary_op_insert_pieces_predicated_1): Insert as predicated values > from pieces. > (fold_const_from_equiv_heads): Fold N-ary expression of equiv-heads. > (push_new_nary_ref): Insert a back-reference to vn_nary_op_t. > (val_equiv_insert): Record temporary equivalence. > (vn_nary_op_insert_pieces_predicated): Record equivalences instead of > some predicates; insert back-refs. > (record_equiv_from_prev_phi_1): Record temporary equivalences > generated > by PHI nodes. > (record_equiv_from_prev_phi): Given an outgoing edge of a conditional > expression taken, record equivalences generated by PHI nodes. > (visit_nary_op): Add lookup previous results of N-ary operations by > equivalences. > (insert_related_predicates_on_edge): Some predicates can be computed > from equivalences, no need to insert them. > (process_bb): Add lookup predicated values by equivalences. > (struct unwind_state): Unwind state of back-refs to vn_nary_op_t. > (do_unwind): Unwind the back-refs to vn_nary_op_t. > (do_rpo_vn): Update back-reference unwind state. > * tree-ssa-sccvn.h (struct nary_ref): hold a lists of references to > the > nary map entries. > > gcc/testsuite/ChangeLog: > > * g++.dg/pr83541.C: Disable fre. > * gcc.dg/tree-ssa/pr68619-2.c: Disable fre. > * gcc.dg/tree-ssa/pr71947-1.c: Disable fre. > * gcc.dg/tree-ssa/pr71947-2.c: Disable fre. > * gcc.dg/tree-ssa/pr71947-3.c: Disable fre. > * gcc.dg/tree-ssa/pr71947-5.c: Disable fre. > * gcc.dg/tree-ssa/pr71947-7.c: Disable fre. > * gcc.dg/tree-ssa/pr71947-8.c: Disable fre. > * gcc.dg/tree-ssa/pr71947-9.c: Disable fre. > * gcc.dg/tree-ssa/vrp03.c: Disable fre. > * gcc.dg/tree-ssa/ssa-fre-100.c: New test. > * gcc.dg/tree-ssa/ssa-fre-101.c: New test. > * gcc.dg/tree-ssa/ssa-fre-102.c: New test. > * gcc.dg/tree-ssa/ssa-pre-34.c: New test.
