diff options
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/ira.c | 81 |
2 files changed, 58 insertions, 30 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 629b9d6..9daedf3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,12 @@ 2016-04-30 Alan Modra <amodra@gmail.com> + * ira.c (enum valid_equiv): New. + (validate_equiv_mem): Return enum. + (update_equiv_mem): Create replacement in more cases. + (add_store_equivs): Update validate_equiv_mem call. + +2016-04-30 Alan Modra <amodra@gmail.com> + * ira.c (combine_and_move_insns): Rather than scanning insns, use DF infrastucture to find use and def insns. @@ -2951,43 +2951,56 @@ validate_equiv_mem_from_store (rtx dest, const_rtx set ATTRIBUTE_UNUSED, info->equiv_mem_modified = true; } +enum valid_equiv { valid_none, valid_combine, valid_reload }; + /* Verify that no store between START and the death of REG invalidates MEMREF. MEMREF is invalidated by modifying a register used in MEMREF, by storing into an overlapping memory location, or with a non-const CALL_INSN. - Return 1 if MEMREF remains valid. */ -static int + Return VALID_RELOAD if MEMREF remains valid for both reload and + combine_and_move insns, VALID_COMBINE if only valid for + combine_and_move_insns, and VALID_NONE otherwise. */ +static enum valid_equiv validate_equiv_mem (rtx_insn *start, rtx reg, rtx memref) { rtx_insn *insn; rtx note; struct equiv_mem_data info = { memref, false }; + enum valid_equiv ret = valid_reload; /* If the memory reference has side effects or is volatile, it isn't a valid equivalence. */ if (side_effects_p (memref)) - return 0; + return valid_none; for (insn = start; insn; insn = NEXT_INSN (insn)) { - if (! INSN_P (insn)) + if (!INSN_P (insn)) continue; if (find_reg_note (insn, REG_DEAD, reg)) - return 1; + return ret; - /* This used to ignore readonly memory and const/pure calls. The problem - is the equivalent form may reference a pseudo which gets assigned a - call clobbered hard reg. When we later replace REG with its - equivalent form, the value in the call-clobbered reg has been - changed and all hell breaks loose. */ if (CALL_P (insn)) - return 0; + { + /* We can combine a reg def from one insn into a reg use in + another over a call if the memory is readonly or the call + const/pure. However, we can't set reg_equiv notes up for + reload over any call. The problem is the equivalent form + may reference a pseudo which gets assigned a call + clobbered hard reg. When we later replace REG with its + equivalent form, the value in the call-clobbered reg has + been changed and all hell breaks loose. */ + ret = valid_combine; + if (!MEM_READONLY_P (memref) + && !RTL_CONST_OR_PURE_CALL_P (insn)) + return valid_none; + } note_stores (PATTERN (insn), validate_equiv_mem_from_store, &info); if (info.equiv_mem_modified) - return 0; + return valid_none; /* If a register mentioned in MEMREF is modified via an auto-increment, we lose the equivalence. Do the same if one @@ -2999,10 +3012,10 @@ validate_equiv_mem (rtx_insn *start, rtx reg, rtx memref) || REG_NOTE_KIND (note) == REG_DEAD) && REG_P (XEXP (note, 0)) && reg_overlap_mentioned_p (XEXP (note, 0), memref)) - return 0; + return valid_none; } - return 0; + return valid_none; } /* Returns zero if X is known to be invariant. */ @@ -3510,24 +3523,32 @@ update_equiv_regs (void) note. */ note = find_reg_note (insn, REG_EQUIV, NULL_RTX); - if (note == NULL_RTX && REG_BASIC_BLOCK (regno) >= NUM_FIXED_BLOCKS - && MEM_P (SET_SRC (set)) - && validate_equiv_mem (insn, dest, SET_SRC (set))) - note = set_unique_reg_note (insn, REG_EQUIV, copy_rtx (SET_SRC (set))); - + rtx replacement = NULL_RTX; if (note) + replacement = XEXP (note, 0); + else if (REG_BASIC_BLOCK (regno) >= NUM_FIXED_BLOCKS + && MEM_P (SET_SRC (set))) { - int regno = REGNO (dest); - rtx x = XEXP (note, 0); + enum valid_equiv validity; + validity = validate_equiv_mem (insn, dest, SET_SRC (set)); + if (validity != valid_none) + { + replacement = copy_rtx (SET_SRC (set)); + if (validity == valid_reload) + note = set_unique_reg_note (insn, REG_EQUIV, replacement); + } + } - /* If we haven't done so, record for reload that this is an - equivalencing insn. */ - if (!reg_equiv[regno].is_arg_equivalence) - ira_reg_equiv[regno].init_insns - = gen_rtx_INSN_LIST (VOIDmode, insn, - ira_reg_equiv[regno].init_insns); + /* If we haven't done so, record for reload that this is an + equivalencing insn. */ + if (note && !reg_equiv[regno].is_arg_equivalence) + ira_reg_equiv[regno].init_insns + = gen_rtx_INSN_LIST (VOIDmode, insn, + ira_reg_equiv[regno].init_insns); - reg_equiv[regno].replacement = x; + if (replacement) + { + reg_equiv[regno].replacement = replacement; reg_equiv[regno].src_p = &SET_SRC (set); reg_equiv[regno].loop_depth = (short) loop_depth; @@ -3548,7 +3569,7 @@ update_equiv_regs (void) calls. */ if (REG_N_REFS (regno) == 2 - && (rtx_equal_p (x, src) + && (rtx_equal_p (replacement, src) || ! equiv_init_varies_p (src)) && NONJUMP_INSN_P (insn) && equiv_init_movable_p (PATTERN (insn), regno)) @@ -3599,7 +3620,7 @@ add_store_equivs (void) && (init_insn = reg_equiv[regno].init_insns->insn ()) != 0 && bitmap_bit_p (&seen_insns, INSN_UID (init_insn)) && ! find_reg_note (init_insn, REG_EQUIV, NULL_RTX) - && validate_equiv_mem (init_insn, src, dest) + && validate_equiv_mem (init_insn, src, dest) == valid_reload && ! memref_used_between_p (dest, init_insn, insn) /* Attaching a REG_EQUIV note will fail if INIT_INSN has multiple sets. */ |