diff options
Diffstat (limited to 'gcc/regmove.c')
| -rw-r--r-- | gcc/regmove.c | 450 |
1 files changed, 6 insertions, 444 deletions
diff --git a/gcc/regmove.c b/gcc/regmove.c index 06272e5..d874695 100644 --- a/gcc/regmove.c +++ b/gcc/regmove.c @@ -623,12 +623,11 @@ optimize_reg_copy_2 (rtx insn, rtx dest, rtx src) if (reg_mentioned_p (dest, PATTERN (q))) PATTERN (q) = replace_rtx (PATTERN (q), dest, src); - - if (CALL_P (q)) - { - REG_N_CALLS_CROSSED (dregno)--; - REG_N_CALLS_CROSSED (sregno)++; - } + if (CALL_P (q)) + { + REG_N_CALLS_CROSSED (dregno)--; + REG_N_CALLS_CROSSED (sregno)++; + } } remove_note (p, find_reg_note (p, REG_DEAD, dest)); @@ -644,6 +643,7 @@ optimize_reg_copy_2 (rtx insn, rtx dest, rtx src) break; } } + /* INSN is a ZERO_EXTEND or SIGN_EXTEND of SRC to DEST. Look if SRC dies there, and if it is only set once, by loading it from memory. If so, try to incorporate the zero/sign extension @@ -2083,408 +2083,13 @@ stable_and_no_regs_but_for_p (rtx x, rtx src, rtx dst) } } -/* Track stack adjustments and stack memory references. Attempt to - reduce the number of stack adjustments by back-propagating across - the memory references. - - This is intended primarily for use with targets that do not define - ACCUMULATE_OUTGOING_ARGS. It is of significantly more value to - targets that define PREFERRED_STACK_BOUNDARY more aligned than - STACK_BOUNDARY (e.g. x86), or if not all registers can be pushed - (e.g. x86 fp regs) which would ordinarily have to be implemented - as a sub/mov pair due to restrictions in calls.c. - - Propagation stops when any of the insns that need adjusting are - (a) no longer valid because we've exceeded their range, (b) a - non-trivial push instruction, or (c) a call instruction. - - Restriction B is based on the assumption that push instructions - are smaller or faster. If a port really wants to remove all - pushes, it should have defined ACCUMULATE_OUTGOING_ARGS. The - one exception that is made is for an add immediately followed - by a push. */ - -/* This structure records stack memory references between stack adjusting - instructions. */ - -struct csa_memlist -{ - HOST_WIDE_INT sp_offset; - rtx insn, *mem; - struct csa_memlist *next; -}; - -static int stack_memref_p (rtx); -static rtx single_set_for_csa (rtx); -static void free_csa_memlist (struct csa_memlist *); -static struct csa_memlist *record_one_stack_memref (rtx, rtx *, - struct csa_memlist *); -static int try_apply_stack_adjustment (rtx, struct csa_memlist *, - HOST_WIDE_INT, HOST_WIDE_INT); -static void combine_stack_adjustments_for_block (basic_block); -static int record_stack_memrefs (rtx *, void *); - - -/* Main entry point for stack adjustment combination. */ - -static void -combine_stack_adjustments (void) -{ - basic_block bb; - - FOR_EACH_BB (bb) - combine_stack_adjustments_for_block (bb); -} - -/* Recognize a MEM of the form (sp) or (plus sp const). */ - -static int -stack_memref_p (rtx x) -{ - if (!MEM_P (x)) - return 0; - x = XEXP (x, 0); - - if (x == stack_pointer_rtx) - return 1; - if (GET_CODE (x) == PLUS - && XEXP (x, 0) == stack_pointer_rtx - && GET_CODE (XEXP (x, 1)) == CONST_INT) - return 1; - - return 0; -} - -/* Recognize either normal single_set or the hack in i386.md for - tying fp and sp adjustments. */ - -static rtx -single_set_for_csa (rtx insn) -{ - int i; - rtx tmp = single_set (insn); - if (tmp) - return tmp; - - if (!NONJUMP_INSN_P (insn) - || GET_CODE (PATTERN (insn)) != PARALLEL) - return NULL_RTX; - - tmp = PATTERN (insn); - if (GET_CODE (XVECEXP (tmp, 0, 0)) != SET) - return NULL_RTX; - - for (i = 1; i < XVECLEN (tmp, 0); ++i) - { - rtx this = XVECEXP (tmp, 0, i); - - /* The special case is allowing a no-op set. */ - if (GET_CODE (this) == SET - && SET_SRC (this) == SET_DEST (this)) - ; - else if (GET_CODE (this) != CLOBBER - && GET_CODE (this) != USE) - return NULL_RTX; - } - return XVECEXP (tmp, 0, 0); -} - -/* Free the list of csa_memlist nodes. */ - -static void -free_csa_memlist (struct csa_memlist *memlist) -{ - struct csa_memlist *next; - for (; memlist ; memlist = next) - { - next = memlist->next; - free (memlist); - } -} - -/* Create a new csa_memlist node from the given memory reference. - It is already known that the memory is stack_memref_p. */ - -static struct csa_memlist * -record_one_stack_memref (rtx insn, rtx *mem, struct csa_memlist *next_memlist) -{ - struct csa_memlist *ml; - - ml = XNEW (struct csa_memlist); - - if (XEXP (*mem, 0) == stack_pointer_rtx) - ml->sp_offset = 0; - else - ml->sp_offset = INTVAL (XEXP (XEXP (*mem, 0), 1)); - - ml->insn = insn; - ml->mem = mem; - ml->next = next_memlist; - - return ml; -} - -/* Attempt to apply ADJUST to the stack adjusting insn INSN, as well - as each of the memories in MEMLIST. Return true on success. */ - -static int -try_apply_stack_adjustment (rtx insn, struct csa_memlist *memlist, HOST_WIDE_INT new_adjust, - HOST_WIDE_INT delta) -{ - struct csa_memlist *ml; - rtx set; - - set = single_set_for_csa (insn); - validate_change (insn, &XEXP (SET_SRC (set), 1), GEN_INT (new_adjust), 1); - - for (ml = memlist; ml ; ml = ml->next) - validate_change - (ml->insn, ml->mem, - replace_equiv_address_nv (*ml->mem, - plus_constant (stack_pointer_rtx, - ml->sp_offset - delta)), 1); - - if (apply_change_group ()) - { - /* Succeeded. Update our knowledge of the memory references. */ - for (ml = memlist; ml ; ml = ml->next) - ml->sp_offset -= delta; - - return 1; - } - else - return 0; -} - -/* Called via for_each_rtx and used to record all stack memory references in - the insn and discard all other stack pointer references. */ -struct record_stack_memrefs_data -{ - rtx insn; - struct csa_memlist *memlist; -}; - -static int -record_stack_memrefs (rtx *xp, void *data) -{ - rtx x = *xp; - struct record_stack_memrefs_data *d = - (struct record_stack_memrefs_data *) data; - if (!x) - return 0; - switch (GET_CODE (x)) - { - case MEM: - if (!reg_mentioned_p (stack_pointer_rtx, x)) - return -1; - /* We are not able to handle correctly all possible memrefs containing - stack pointer, so this check is necessary. */ - if (stack_memref_p (x)) - { - d->memlist = record_one_stack_memref (d->insn, xp, d->memlist); - return -1; - } - return 1; - case REG: - /* ??? We want be able to handle non-memory stack pointer - references later. For now just discard all insns referring to - stack pointer outside mem expressions. We would probably - want to teach validate_replace to simplify expressions first. - - We can't just compare with STACK_POINTER_RTX because the - reference to the stack pointer might be in some other mode. - In particular, an explicit clobber in an asm statement will - result in a QImode clobber. */ - if (REGNO (x) == STACK_POINTER_REGNUM) - return 1; - break; - default: - break; - } - return 0; -} - -/* Subroutine of combine_stack_adjustments, called for each basic block. */ - -static void -combine_stack_adjustments_for_block (basic_block bb) -{ - HOST_WIDE_INT last_sp_adjust = 0; - rtx last_sp_set = NULL_RTX; - struct csa_memlist *memlist = NULL; - rtx insn, next, set; - struct record_stack_memrefs_data data; - bool end_of_block = false; - - for (insn = BB_HEAD (bb); !end_of_block ; insn = next) - { - end_of_block = insn == BB_END (bb); - next = NEXT_INSN (insn); - - if (! INSN_P (insn)) - continue; - - set = single_set_for_csa (insn); - if (set) - { - rtx dest = SET_DEST (set); - rtx src = SET_SRC (set); - - /* Find constant additions to the stack pointer. */ - if (dest == stack_pointer_rtx - && GET_CODE (src) == PLUS - && XEXP (src, 0) == stack_pointer_rtx - && GET_CODE (XEXP (src, 1)) == CONST_INT) - { - HOST_WIDE_INT this_adjust = INTVAL (XEXP (src, 1)); - - /* If we've not seen an adjustment previously, record - it now and continue. */ - if (! last_sp_set) - { - last_sp_set = insn; - last_sp_adjust = this_adjust; - continue; - } - - /* If not all recorded memrefs can be adjusted, or the - adjustment is now too large for a constant addition, - we cannot merge the two stack adjustments. - - Also we need to be careful to not move stack pointer - such that we create stack accesses outside the allocated - area. We can combine an allocation into the first insn, - or a deallocation into the second insn. We can not - combine an allocation followed by a deallocation. - - The only somewhat frequent occurrence of the later is when - a function allocates a stack frame but does not use it. - For this case, we would need to analyze rtl stream to be - sure that allocated area is really unused. This means not - only checking the memory references, but also all registers - or global memory references possibly containing a stack - frame address. - - Perhaps the best way to address this problem is to teach - gcc not to allocate stack for objects never used. */ - - /* Combine an allocation into the first instruction. */ - if (STACK_GROWS_DOWNWARD ? this_adjust <= 0 : this_adjust >= 0) - { - if (try_apply_stack_adjustment (last_sp_set, memlist, - last_sp_adjust + this_adjust, - this_adjust)) - { - /* It worked! */ - delete_insn (insn); - last_sp_adjust += this_adjust; - continue; - } - } - - /* Otherwise we have a deallocation. Do not combine with - a previous allocation. Combine into the second insn. */ - else if (STACK_GROWS_DOWNWARD - ? last_sp_adjust >= 0 : last_sp_adjust <= 0) - { - if (try_apply_stack_adjustment (insn, memlist, - last_sp_adjust + this_adjust, - -last_sp_adjust)) - { - /* It worked! */ - delete_insn (last_sp_set); - last_sp_set = insn; - last_sp_adjust += this_adjust; - free_csa_memlist (memlist); - memlist = NULL; - continue; - } - } - - /* Combination failed. Restart processing from here. If - deallocation+allocation conspired to cancel, we can - delete the old deallocation insn. */ - if (last_sp_set && last_sp_adjust == 0) - delete_insn (insn); - free_csa_memlist (memlist); - memlist = NULL; - last_sp_set = insn; - last_sp_adjust = this_adjust; - continue; - } - - /* Find a predecrement of exactly the previous adjustment and - turn it into a direct store. Obviously we can't do this if - there were any intervening uses of the stack pointer. */ - if (memlist == NULL - && MEM_P (dest) - && ((GET_CODE (XEXP (dest, 0)) == PRE_DEC - && (last_sp_adjust - == (HOST_WIDE_INT) GET_MODE_SIZE (GET_MODE (dest)))) - || (GET_CODE (XEXP (dest, 0)) == PRE_MODIFY - && GET_CODE (XEXP (XEXP (dest, 0), 1)) == PLUS - && XEXP (XEXP (XEXP (dest, 0), 1), 0) == stack_pointer_rtx - && (GET_CODE (XEXP (XEXP (XEXP (dest, 0), 1), 1)) - == CONST_INT) - && (INTVAL (XEXP (XEXP (XEXP (dest, 0), 1), 1)) - == -last_sp_adjust))) - && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx - && ! reg_mentioned_p (stack_pointer_rtx, src) - && memory_address_p (GET_MODE (dest), stack_pointer_rtx) - && validate_change (insn, &SET_DEST (set), - replace_equiv_address (dest, - stack_pointer_rtx), - 0)) - { - delete_insn (last_sp_set); - free_csa_memlist (memlist); - memlist = NULL; - last_sp_set = NULL_RTX; - last_sp_adjust = 0; - continue; - } - } - - data.insn = insn; - data.memlist = memlist; - if (!CALL_P (insn) && last_sp_set - && !for_each_rtx (&PATTERN (insn), record_stack_memrefs, &data)) - { - memlist = data.memlist; - continue; - } - memlist = data.memlist; - - /* Otherwise, we were not able to process the instruction. - Do not continue collecting data across such a one. */ - if (last_sp_set - && (CALL_P (insn) - || reg_mentioned_p (stack_pointer_rtx, PATTERN (insn)))) - { - if (last_sp_set && last_sp_adjust == 0) - delete_insn (last_sp_set); - free_csa_memlist (memlist); - memlist = NULL; - last_sp_set = NULL_RTX; - last_sp_adjust = 0; - } - } - - if (last_sp_set && last_sp_adjust == 0) - delete_insn (last_sp_set); - - if (memlist) - free_csa_memlist (memlist); -} - static bool gate_handle_regmove (void) { return (optimize > 0 && flag_regmove); } - /* Register allocation pre-pass, to reduce number of moves necessary for two-address machines. */ static unsigned int @@ -2513,46 +2118,3 @@ struct tree_opt_pass pass_regmove = 'N' /* letter */ }; - -static bool -gate_handle_stack_adjustments (void) -{ - return (optimize > 0); -} - -static unsigned int -rest_of_handle_stack_adjustments (void) -{ - life_analysis (PROP_POSTRELOAD); - cleanup_cfg (CLEANUP_EXPENSIVE | CLEANUP_UPDATE_LIFE - | (flag_crossjumping ? CLEANUP_CROSSJUMP : 0)); - - /* This is kind of a heuristic. We need to run combine_stack_adjustments - even for machines with possibly nonzero RETURN_POPS_ARGS - and ACCUMULATE_OUTGOING_ARGS. We expect that only ports having - push instructions will have popping returns. */ -#ifndef PUSH_ROUNDING - if (!ACCUMULATE_OUTGOING_ARGS) -#endif - combine_stack_adjustments (); - return 0; -} - -struct tree_opt_pass pass_stack_adjustments = -{ - "csa", /* name */ - gate_handle_stack_adjustments, /* gate */ - rest_of_handle_stack_adjustments, /* execute */ - NULL, /* sub */ - NULL, /* next */ - 0, /* static_pass_number */ - 0, /* tv_id */ - 0, /* properties_required */ - 0, /* properties_provided */ - 0, /* properties_destroyed */ - 0, /* todo_flags_start */ - TODO_dump_func | - TODO_ggc_collect, /* todo_flags_finish */ - 0 /* letter */ -}; - |