Bootstrapped and regtested on x86_64-redhat-linux, ppc64le-redhat-linux and s390x-redhat-linux. Ok for master?
Commit efb6bc55a93a ("fwprop: Allow (subreg (mem)) simplifications") introduced a check that was supposed to look at the propagated def's number of uses. It uses insn_info::num_uses (), which in reality returns the number of uses def's insn has. The whole change therefore works only by accident. Fix by looking at def_info's uses instead of insn_info's uses. This requires passing around def_info instead of insn_info. gcc/ChangeLog: 2021-03-02 Ilya Leoshkevich <i...@linux.ibm.com> * fwprop.c (def_has_single_use_p): New function. (fwprop_propagation::fwprop_propagation): Look at def_info's uses. (try_fwprop_subst_note): Use def_info instead of insn_info. (try_fwprop_subst_pattern): Likewise. (try_fwprop_subst_notes): Likewise. (try_fwprop_subst): Likewise. (forward_propagate_subreg): Likewise. (forward_propagate_and_simplify): Likewise. (forward_propagate_into): Likewise. * iterator-utils.h (single_element_p): New function. --- gcc/fwprop.c | 89 ++++++++++++++++++++++++++------------------ gcc/iterator-utils.h | 10 +++++ 2 files changed, 62 insertions(+), 37 deletions(-) diff --git a/gcc/fwprop.c b/gcc/fwprop.c index 4b8a554e823..478dcdd96cc 100644 --- a/gcc/fwprop.c +++ b/gcc/fwprop.c @@ -175,7 +175,7 @@ namespace static const uint16_t CONSTANT = FIRST_SPARE_RESULT << 1; static const uint16_t PROFITABLE = FIRST_SPARE_RESULT << 2; - fwprop_propagation (insn_info *, insn_info *, rtx, rtx); + fwprop_propagation (insn_info *, def_info *, rtx, rtx); bool changed_mem_p () const { return result_flags & CHANGED_MEM; } bool folded_to_constants_p () const; @@ -191,13 +191,27 @@ namespace }; } -/* Prepare to replace FROM with TO in INSN. */ +/* Return true if DEF has a single non-debug non-phi use. */ + +static bool +def_has_single_use_p (def_info *def) +{ + if (!is_a<set_info *> (def)) + return false; + + set_info *set = as_a<set_info *> (def); + + return single_element_p (set->nondebug_insn_uses ()) + && !set->has_phi_uses (); +} + +/* Prepare to replace FROM with TO in USE_INSN. */ fwprop_propagation::fwprop_propagation (insn_info *use_insn, - insn_info *def_insn, rtx from, rtx to) + def_info *def, rtx from, rtx to) : insn_propagation (use_insn->rtl (), from, to), - single_use_p (def_insn->num_uses () == 1), - single_ebb_p (use_insn->ebb () == def_insn->ebb ()) + single_use_p (def_has_single_use_p (def)), + single_ebb_p (use_insn->ebb () == def->insn ()->ebb ()) { should_check_mems = true; should_note_simplifications = true; @@ -368,9 +382,9 @@ contains_paradoxical_subreg_p (rtx x) return false; } -/* Try to substitute (set DEST SRC) from DEF_INSN into note NOTE of USE_INSN. - Return the number of substitutions on success, otherwise return -1 and - leave USE_INSN unchanged. +/* Try to substitute (set DEST SRC), which defines DEF, into note NOTE of + USE_INSN. Return the number of substitutions on success, otherwise return + -1 and leave USE_INSN unchanged. If REQUIRE_CONSTANT is true, require all substituted occurences of SRC to fold to a constant, so that the note does not use any more registers @@ -379,13 +393,14 @@ contains_paradoxical_subreg_p (rtx x) instruction pattern. */ static int -try_fwprop_subst_note (insn_info *use_insn, insn_info *def_insn, +try_fwprop_subst_note (insn_info *use_insn, def_info *def, rtx note, rtx dest, rtx src, bool require_constant) { rtx_insn *use_rtl = use_insn->rtl (); + insn_info *def_insn = def->insn (); insn_change_watermark watermark; - fwprop_propagation prop (use_insn, def_insn, dest, src); + fwprop_propagation prop (use_insn, def, dest, src); if (!prop.apply_to_rvalue (&XEXP (note, 0))) { if (dump_file && (dump_flags & TDF_DETAILS)) @@ -436,19 +451,20 @@ try_fwprop_subst_note (insn_info *use_insn, insn_info *def_insn, return prop.num_replacements; } -/* Try to substitute (set DEST SRC) from DEF_INSN into location LOC of +/* Try to substitute (set DEST SRC), which defines DEF, into location LOC of USE_INSN's pattern. Return true on success, otherwise leave USE_INSN unchanged. */ static bool try_fwprop_subst_pattern (obstack_watermark &attempt, insn_change &use_change, - insn_info *def_insn, rtx *loc, rtx dest, rtx src) + def_info *def, rtx *loc, rtx dest, rtx src) { insn_info *use_insn = use_change.insn (); rtx_insn *use_rtl = use_insn->rtl (); + insn_info *def_insn = def->insn (); insn_change_watermark watermark; - fwprop_propagation prop (use_insn, def_insn, dest, src); + fwprop_propagation prop (use_insn, def, dest, src); if (!prop.apply_to_pattern (loc)) { if (dump_file && (dump_flags & TDF_DETAILS)) @@ -538,7 +554,7 @@ try_fwprop_subst_pattern (obstack_watermark &attempt, insn_change &use_change, { if ((REG_NOTE_KIND (note) == REG_EQUAL || REG_NOTE_KIND (note) == REG_EQUIV) - && try_fwprop_subst_note (use_insn, def_insn, note, + && try_fwprop_subst_note (use_insn, def, note, dest, src, false) < 0) { *note_ptr = XEXP (note, 1); @@ -554,19 +570,19 @@ try_fwprop_subst_pattern (obstack_watermark &attempt, insn_change &use_change, return true; } -/* Try to substitute (set DEST SRC) from DEF_INSN into USE_INSN's notes, +/* Try to substitute (set DEST SRC), which defines DEF, into USE_INSN's notes, given that it was not possible to do this for USE_INSN's main pattern. Return true on success, otherwise leave USE_INSN unchanged. */ static bool -try_fwprop_subst_notes (insn_info *use_insn, insn_info *def_insn, +try_fwprop_subst_notes (insn_info *use_insn, def_info *def, rtx dest, rtx src) { rtx_insn *use_rtl = use_insn->rtl (); for (rtx note = REG_NOTES (use_rtl); note; note = XEXP (note, 1)) if ((REG_NOTE_KIND (note) == REG_EQUAL || REG_NOTE_KIND (note) == REG_EQUIV) - && try_fwprop_subst_note (use_insn, def_insn, note, + && try_fwprop_subst_note (use_insn, def, note, dest, src, true) > 0) { confirm_change_group (); @@ -576,7 +592,7 @@ try_fwprop_subst_notes (insn_info *use_insn, insn_info *def_insn, return false; } -/* Check whether we could validly substitute (set DEST SRC) from DEF_INSN +/* Check whether we could validly substitute (set DEST SRC), which defines DEF, into USE. If so, first try performing the substitution in location LOC of USE->insn ()'s pattern. If that fails, try instead to substitute into the notes. @@ -584,10 +600,11 @@ try_fwprop_subst_notes (insn_info *use_insn, insn_info *def_insn, Return true on success, otherwise leave USE_INSN unchanged. */ static bool -try_fwprop_subst (use_info *use, insn_info *def_insn, +try_fwprop_subst (use_info *use, def_info *def, rtx *loc, rtx dest, rtx src) { insn_info *use_insn = use->insn (); + insn_info *def_insn = def->insn (); auto attempt = crtl->ssa->new_change_attempt (); use_array src_uses = remove_note_accesses (attempt, def_insn->uses ()); @@ -622,9 +639,8 @@ try_fwprop_subst (use_info *use, insn_info *def_insn, if (!restrict_movement (use_change)) return false; - return (try_fwprop_subst_pattern (attempt, use_change, def_insn, - loc, dest, src) - || try_fwprop_subst_notes (use_insn, def_insn, dest, src)); + return (try_fwprop_subst_pattern (attempt, use_change, def, loc, dest, src) + || try_fwprop_subst_notes (use_insn, def, dest, src)); } /* For the given single_set INSN, containing SRC known to be a @@ -671,7 +687,7 @@ free_load_extend (rtx src, insn_info *insn) in REF. The other parameters are the same. */ static bool -forward_propagate_subreg (use_info *use, insn_info *def_insn, +forward_propagate_subreg (use_info *use, def_info *def, rtx dest, rtx src, df_ref ref) { scalar_int_mode int_use_mode, src_mode; @@ -697,8 +713,7 @@ forward_propagate_subreg (use_info *use, insn_info *def_insn, && REGNO (SUBREG_REG (src)) >= FIRST_PSEUDO_REGISTER && GET_MODE (SUBREG_REG (src)) == use_mode && subreg_lowpart_p (src)) - return try_fwprop_subst (use, def_insn, loc, - use_reg, SUBREG_REG (src)); + return try_fwprop_subst (use, def, loc, use_reg, SUBREG_REG (src)); } /* If this is a SUBREG of a ZERO_EXTEND or SIGN_EXTEND, and the SUBREG @@ -725,22 +740,21 @@ forward_propagate_subreg (use_info *use, insn_info *def_insn, && REG_P (XEXP (src, 0)) && REGNO (XEXP (src, 0)) >= FIRST_PSEUDO_REGISTER && GET_MODE (XEXP (src, 0)) == use_mode - && !free_load_extend (src, def_insn) + && !free_load_extend (src, def->insn ()) && (targetm.mode_rep_extended (int_use_mode, src_mode) != (int) GET_CODE (src))) - return try_fwprop_subst (use, def_insn, loc, use_reg, XEXP (src, 0)); + return try_fwprop_subst (use, def, loc, use_reg, XEXP (src, 0)); } return false; } -/* Try to substitute (set DEST SRC) from DEF_INSN into USE and simplify +/* Try to substitute (set DEST SRC), which defines DEF, into USE and simplify the result, handling cases where DEST is used in a subreg and where applying that subreg to SRC results in a useful simplification. */ static bool -forward_propagate_subreg (use_info *use, insn_info *def_insn, - rtx dest, rtx src) +forward_propagate_subreg (use_info *use, def_info *def, rtx dest, rtx src) { if (!use->includes_subregs () || !REG_P (dest)) return false; @@ -755,26 +769,27 @@ forward_propagate_subreg (use_info *use, insn_info *def_insn, FOR_EACH_INSN_USE (ref, use_rtl) if (DF_REF_REGNO (ref) == use->regno () - && forward_propagate_subreg (use, def_insn, dest, src, ref)) + && forward_propagate_subreg (use, def, dest, src, ref)) return true; FOR_EACH_INSN_EQ_USE (ref, use_rtl) if (DF_REF_REGNO (ref) == use->regno () - && forward_propagate_subreg (use, def_insn, dest, src, ref)) + && forward_propagate_subreg (use, def, dest, src, ref)) return true; return false; } -/* Try to substitute (set DEST SRC) from DEF_INSN into USE and +/* Try to substitute (set DEST SRC), which defines DEF, into USE and simplify the result. */ static bool -forward_propagate_and_simplify (use_info *use, insn_info *def_insn, +forward_propagate_and_simplify (use_info *use, def_info *def, rtx dest, rtx src) { insn_info *use_insn = use->insn (); rtx_insn *use_rtl = use_insn->rtl (); + insn_info *def_insn = def->insn (); /* ??? This check seems unnecessary. We should be able to propagate into any kind of instruction, regardless of whether it's a single set. @@ -820,7 +835,7 @@ forward_propagate_and_simplify (use_info *use, insn_info *def_insn, /* ??? Unconditionally propagating into PATTERN would work better for instructions that have match_dups. */ rtx *loc = need_single_set ? &use_set : &PATTERN (use_rtl); - return try_fwprop_subst (use, def_insn, loc, dest, src); + return try_fwprop_subst (use, def, loc, dest, src); } /* Given a use USE of an insn, if it has a single reaching @@ -880,8 +895,8 @@ forward_propagate_into (use_info *use, bool reg_prop_only = false) && find_reg_note (use_rtl, REG_NON_LOCAL_GOTO, NULL_RTX)) return false; - if (forward_propagate_and_simplify (use, def_insn, dest, src) - || forward_propagate_subreg (use, def_insn, dest, src)) + if (forward_propagate_and_simplify (use, def, dest, src) + || forward_propagate_subreg (use, def, dest, src)) return true; return false; diff --git a/gcc/iterator-utils.h b/gcc/iterator-utils.h index a02dfcc3c8f..01a7d5c947e 100644 --- a/gcc/iterator-utils.h +++ b/gcc/iterator-utils.h @@ -200,4 +200,14 @@ list_iterator<T, Next>::operator++ (int) return ret; } +// Return true if CONTAINER has precisely one element. +template <typename T> +bool +single_element_p (const T &container) +{ + auto it = container.begin (); + auto end = container.end (); + return it != end && ++it == end; +} + #endif -- 2.29.2