On Tue, Apr 5, 2011 at 3:59 PM, Nathan Froyd <froy...@codesourcery.com> wrote:
> On Mon, Apr 04, 2011 at 02:49:54PM -0400, Nathan Froyd wrote:
>> This patch does just what $SUBJECT suggests.
>
> v2, now with obstacks!
>
> Tested on x86_64-unknown-linux-gnu. OK to commit?
Ok.
Thanks,
Richard.
> -Nathan
>
> * combine.c: Include obstack.h
> (struct insn_link): Define.
> (uid_log_links): Adjust type.
> (FOR_EACH_LOG_LINK): New macro.
> (insn_link_obstack): Declare.
> (alloc_insn_link): Define.
> (create_log_links): Call it. Use FOR_EACH_LOG_LINK and adjust
> type of link variables.
> (find_single_use, insn_a_feeds_b, combine_instructions): Likewise.
> (try_combine, record_promoted_values, distribute_notes): Likewise.
> (distribute_links): Likewise. Tweak prototype.
> (clear_log_links): Delete.
> (adjust_for_new_dest): Call alloc_insn_link.
> * Makefile.in (combine.o): Depend on $(OBSTACK_H).
>
> diff --git a/gcc/Makefile.in b/gcc/Makefile.in
> index 16779bd..d47a69e 100644
> --- a/gcc/Makefile.in
> +++ b/gcc/Makefile.in
> @@ -3247,7 +3247,8 @@ combine.o : combine.c $(CONFIG_H) $(SYSTEM_H)
> coretypes.h $(TM_H) $(RTL_H) \
> $(FLAGS_H) $(FUNCTION_H) insn-config.h $(INSN_ATTR_H) $(REGS_H) $(EXPR_H) \
> rtlhooks-def.h $(BASIC_BLOCK_H) $(RECOG_H) hard-reg-set.h \
> $(DIAGNOSTIC_CORE_H) $(TM_P_H) $(TREE_H) $(TARGET_H) output.h $(PARAMS_H)
> $(OPTABS_H) \
> - insn-codes.h $(TIMEVAR_H) $(TREE_PASS_H) $(DF_H) vecprim.h $(CGRAPH_H)
> + insn-codes.h $(TIMEVAR_H) $(TREE_PASS_H) $(DF_H) vecprim.h $(CGRAPH_H) \
> + $(OBSTACK_H)
> reginfo.o : reginfo.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
> hard-reg-set.h $(FLAGS_H) $(BASIC_BLOCK_H) addresses.h $(REGS_H) \
> insn-config.h $(RECOG_H) reload.h $(DIAGNOSTIC_CORE_H) \
> diff --git a/gcc/combine.c b/gcc/combine.c
> index 37236cc..30b7fdd 100644
> --- a/gcc/combine.c
> +++ b/gcc/combine.c
> @@ -104,6 +104,7 @@ along with GCC; see the file COPYING3. If not see
> #include "tree-pass.h"
> #include "df.h"
> #include "cgraph.h"
> +#include "obstack.h"
>
> /* Number of attempts to combine instructions in this function. */
>
> @@ -309,13 +310,38 @@ static int max_uid_known;
> static int *uid_insn_cost;
>
> /* The following array records the LOG_LINKS for every insn in the
> - instruction stream as an INSN_LIST rtx. */
> + instruction stream as struct insn_link pointers. */
>
> -static rtx *uid_log_links;
> +struct insn_link {
> + rtx insn;
> + struct insn_link *next;
> +};
> +
> +static struct insn_link **uid_log_links;
>
> #define INSN_COST(INSN) (uid_insn_cost[INSN_UID (INSN)])
> #define LOG_LINKS(INSN) (uid_log_links[INSN_UID (INSN)])
>
> +#define FOR_EACH_LOG_LINK(L, INSN) \
> + for ((L) = LOG_LINKS (INSN); (L); (L) = (L)->next)
> +
> +/* Links for LOG_LINKS are allocated from this obstack. */
> +
> +static struct obstack insn_link_obstack;
> +
> +/* Allocate a link. */
> +
> +static inline struct insn_link *
> +alloc_insn_link (rtx insn, struct insn_link *next)
> +{
> + struct insn_link *l
> + = (struct insn_link *) obstack_alloc (&insn_link_obstack,
> + sizeof (struct insn_link));
> + l->insn = insn;
> + l->next = next;
> + return l;
> +}
> +
> /* Incremented for each basic block. */
>
> static int label_tick;
> @@ -438,7 +464,7 @@ static int reg_dead_at_p (rtx, rtx);
> static void move_deaths (rtx, rtx, int, rtx, rtx *);
> static int reg_bitfield_target_p (rtx, rtx);
> static void distribute_notes (rtx, rtx, rtx, rtx, rtx, rtx, rtx);
> -static void distribute_links (rtx);
> +static void distribute_links (struct insn_link *);
> static void mark_used_regs_combine (rtx);
> static void record_promoted_value (rtx, rtx);
> static int unmentioned_reg_p_1 (rtx *, void *);
> @@ -609,7 +635,7 @@ find_single_use (rtx dest, rtx insn, rtx *ploc)
> basic_block bb;
> rtx next;
> rtx *result;
> - rtx link;
> + struct insn_link *link;
>
> #ifdef HAVE_cc0
> if (dest == cc0_rtx)
> @@ -635,8 +661,8 @@ find_single_use (rtx dest, rtx insn, rtx *ploc)
> next = NEXT_INSN (next))
> if (INSN_P (next) && dead_or_set_p (next, dest))
> {
> - for (link = LOG_LINKS (next); link; link = XEXP (link, 1))
> - if (XEXP (link, 0) == insn)
> + FOR_EACH_LOG_LINK (link, next)
> + if (link->insn == insn)
> break;
>
> if (link)
> @@ -985,15 +1011,14 @@ create_log_links (void)
> || asm_noperands (PATTERN (use_insn)) < 0)
> {
> /* Don't add duplicate links between instructions. */
> - rtx links;
> - for (links = LOG_LINKS (use_insn); links;
> - links = XEXP (links, 1))
> - if (insn == XEXP (links, 0))
> + struct insn_link *links;
> + FOR_EACH_LOG_LINK (links, use_insn)
> + if (insn == links->insn)
> break;
>
> if (!links)
> - LOG_LINKS (use_insn) =
> - alloc_INSN_LIST (insn, LOG_LINKS (use_insn));
> + LOG_LINKS (use_insn)
> + = alloc_insn_link (insn, LOG_LINKS (use_insn));
> }
> }
> next_use[regno] = NULL_RTX;
> @@ -1017,18 +1042,6 @@ create_log_links (void)
> free (next_use);
> }
>
> -/* Clear LOG_LINKS fields of insns. */
> -
> -static void
> -clear_log_links (void)
> -{
> - rtx insn;
> -
> - for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
> - if (INSN_P (insn))
> - free_INSN_LIST_list (&LOG_LINKS (insn));
> -}
> -
> /* Walk the LOG_LINKS of insn B to see if we find a reference to A. Return
> true if we found a LOG_LINK that proves that A feeds B. This only works
> if there are no instructions between A and B which could have a link
> @@ -1039,9 +1052,9 @@ clear_log_links (void)
> static bool
> insn_a_feeds_b (rtx a, rtx b)
> {
> - rtx links;
> - for (links = LOG_LINKS (b); links; links = XEXP (links, 1))
> - if (XEXP (links, 0) == a)
> + struct insn_link *links;
> + FOR_EACH_LOG_LINK (links, b)
> + if (links->insn == a)
> return true;
> #ifdef HAVE_cc0
> if (sets_cc0_p (a))
> @@ -1062,7 +1075,7 @@ combine_instructions (rtx f, unsigned int nregs)
> #ifdef HAVE_cc0
> rtx prev;
> #endif
> - rtx links, nextlinks;
> + struct insn_link *links, *nextlinks;
> rtx first;
> basic_block last_bb;
>
> @@ -1086,8 +1099,9 @@ combine_instructions (rtx f, unsigned int nregs)
>
> /* Allocate array for insn info. */
> max_uid_known = get_max_uid ();
> - uid_log_links = XCNEWVEC (rtx, max_uid_known + 1);
> + uid_log_links = XCNEWVEC (struct insn_link *, max_uid_known + 1);
> uid_insn_cost = XCNEWVEC (int, max_uid_known + 1);
> + gcc_obstack_init (&insn_link_obstack);
>
> nonzero_bits_mode = mode_for_size (HOST_BITS_PER_WIDE_INT, MODE_INT, 0);
>
> @@ -1188,26 +1202,24 @@ combine_instructions (rtx f, unsigned int nregs)
>
> /* Try this insn with each insn it links back to. */
>
> - for (links = LOG_LINKS (insn); links; links = XEXP (links, 1))
> - if ((next = try_combine (insn, XEXP (links, 0), NULL_RTX,
> + FOR_EACH_LOG_LINK (links, insn)
> + if ((next = try_combine (insn, links->insn, NULL_RTX,
> NULL_RTX, &new_direct_jump_p)) != 0)
> goto retry;
>
> /* Try each sequence of three linked insns ending with this one.
> */
>
> - for (links = LOG_LINKS (insn); links; links = XEXP (links, 1))
> + FOR_EACH_LOG_LINK (links, insn)
> {
> - rtx link = XEXP (links, 0);
> + rtx link = links->insn;
>
> /* If the linked insn has been replaced by a note, then there
> is no point in pursuing this chain any further. */
> if (NOTE_P (link))
> continue;
>
> - for (nextlinks = LOG_LINKS (link);
> - nextlinks;
> - nextlinks = XEXP (nextlinks, 1))
> - if ((next = try_combine (insn, link, XEXP (nextlinks, 0),
> + FOR_EACH_LOG_LINK (nextlinks, link)
> + if ((next = try_combine (insn, link, nextlinks->insn,
> NULL_RTX,
> &new_direct_jump_p)) != 0)
> goto retry;
> @@ -1230,9 +1242,8 @@ combine_instructions (rtx f, unsigned int nregs)
> &new_direct_jump_p)) != 0)
> goto retry;
>
> - for (nextlinks = LOG_LINKS (prev); nextlinks;
> - nextlinks = XEXP (nextlinks, 1))
> - if ((next = try_combine (insn, prev, XEXP (nextlinks, 0),
> + FOR_EACH_LOG_LINK (nextlinks, prev)
> + if ((next = try_combine (insn, prev, nextlinks->insn,
> NULL_RTX,
> &new_direct_jump_p)) != 0)
> goto retry;
> @@ -1250,9 +1261,8 @@ combine_instructions (rtx f, unsigned int nregs)
> &new_direct_jump_p)) != 0)
> goto retry;
>
> - for (nextlinks = LOG_LINKS (prev); nextlinks;
> - nextlinks = XEXP (nextlinks, 1))
> - if ((next = try_combine (insn, prev, XEXP (nextlinks, 0),
> + FOR_EACH_LOG_LINK (nextlinks, prev)
> + if ((next = try_combine (insn, prev, nextlinks->insn,
> NULL_RTX,
> &new_direct_jump_p)) != 0)
> goto retry;
> @@ -1261,14 +1271,14 @@ combine_instructions (rtx f, unsigned int nregs)
> /* Finally, see if any of the insns that this insn links to
> explicitly references CC0. If so, try this insn, that insn,
> and its predecessor if it sets CC0. */
> - for (links = LOG_LINKS (insn); links; links = XEXP (links, 1))
> - if (NONJUMP_INSN_P (XEXP (links, 0))
> - && GET_CODE (PATTERN (XEXP (links, 0))) == SET
> - && reg_mentioned_p (cc0_rtx, SET_SRC (PATTERN (XEXP
> (links, 0))))
> - && (prev = prev_nonnote_insn (XEXP (links, 0))) != 0
> + FOR_EACH_LOG_LINK (links, insn)
> + if (NONJUMP_INSN_P (links->insn)
> + && GET_CODE (PATTERN (links->insn)) == SET
> + && reg_mentioned_p (cc0_rtx, SET_SRC (PATTERN
> (links->insn)))
> + && (prev = prev_nonnote_insn (links->insn)) != 0
> && NONJUMP_INSN_P (prev)
> && sets_cc0_p (PATTERN (prev))
> - && (next = try_combine (insn, XEXP (links, 0),
> + && (next = try_combine (insn, links->insn,
> prev, NULL_RTX,
> &new_direct_jump_p)) != 0)
> goto retry;
> @@ -1276,73 +1286,70 @@ combine_instructions (rtx f, unsigned int nregs)
>
> /* Try combining an insn with two different insns whose results
> it
> uses. */
> - for (links = LOG_LINKS (insn); links; links = XEXP (links, 1))
> - for (nextlinks = XEXP (links, 1); nextlinks;
> - nextlinks = XEXP (nextlinks, 1))
> - if ((next = try_combine (insn, XEXP (links, 0),
> - XEXP (nextlinks, 0), NULL_RTX,
> + FOR_EACH_LOG_LINK (links, insn)
> + for (nextlinks = links->next; nextlinks;
> + nextlinks = nextlinks->next)
> + if ((next = try_combine (insn, links->insn,
> + nextlinks->insn, NULL_RTX,
> &new_direct_jump_p)) != 0)
> goto retry;
>
> /* Try four-instruction combinations. */
> - for (links = LOG_LINKS (insn); links; links = XEXP (links, 1))
> + FOR_EACH_LOG_LINK (links, insn)
> {
> - rtx next1;
> - rtx link = XEXP (links, 0);
> + struct insn_link *next1;
> + rtx link = links->insn;
>
> /* If the linked insn has been replaced by a note, then there
> is no point in pursuing this chain any further. */
> if (NOTE_P (link))
> continue;
>
> - for (next1 = LOG_LINKS (link); next1; next1 = XEXP (next1,
> 1))
> + FOR_EACH_LOG_LINK (next1, link)
> {
> - rtx link1 = XEXP (next1, 0);
> + rtx link1 = next1->insn;
> if (NOTE_P (link1))
> continue;
> /* I0 -> I1 -> I2 -> I3. */
> - for (nextlinks = LOG_LINKS (link1); nextlinks;
> - nextlinks = XEXP (nextlinks, 1))
> + FOR_EACH_LOG_LINK (nextlinks, link1)
> if ((next = try_combine (insn, link, link1,
> - XEXP (nextlinks, 0),
> + nextlinks->insn,
> &new_direct_jump_p)) != 0)
> goto retry;
> /* I0, I1 -> I2, I2 -> I3. */
> - for (nextlinks = XEXP (next1, 1); nextlinks;
> - nextlinks = XEXP (nextlinks, 1))
> + for (nextlinks = next1->next; nextlinks;
> + nextlinks = nextlinks->next)
> if ((next = try_combine (insn, link, link1,
> - XEXP (nextlinks, 0),
> + nextlinks->insn,
> &new_direct_jump_p)) != 0)
> goto retry;
> }
>
> - for (next1 = XEXP (links, 1); next1; next1 = XEXP (next1,
> 1))
> + for (next1 = links->next; next1; next1 = next1->next)
> {
> - rtx link1 = XEXP (next1, 0);
> + rtx link1 = next1->insn;
> if (NOTE_P (link1))
> continue;
> /* I0 -> I2; I1, I2 -> I3. */
> - for (nextlinks = LOG_LINKS (link); nextlinks;
> - nextlinks = XEXP (nextlinks, 1))
> + FOR_EACH_LOG_LINK (nextlinks, link)
> if ((next = try_combine (insn, link, link1,
> - XEXP (nextlinks, 0),
> + nextlinks->insn,
> &new_direct_jump_p)) != 0)
> goto retry;
> /* I0 -> I1; I1, I2 -> I3. */
> - for (nextlinks = LOG_LINKS (link1); nextlinks;
> - nextlinks = XEXP (nextlinks, 1))
> + FOR_EACH_LOG_LINK (nextlinks, link1)
> if ((next = try_combine (insn, link, link1,
> - XEXP (nextlinks, 0),
> + nextlinks->insn,
> &new_direct_jump_p)) != 0)
> goto retry;
> }
> }
>
> /* Try this insn with each REG_EQUAL note it links back to. */
> - for (links = LOG_LINKS (insn); links; links = XEXP (links, 1))
> + FOR_EACH_LOG_LINK (links, insn)
> {
> rtx set, note;
> - rtx temp = XEXP (links, 0);
> + rtx temp = links->insn;
> if ((set = single_set (temp)) != 0
> && (note = find_reg_equal_equiv_note (temp)) != 0
> && (note = XEXP (note, 0), GET_CODE (note)) != EXPR_LIST
> @@ -1380,12 +1387,12 @@ combine_instructions (rtx f, unsigned int nregs)
> }
>
> default_rtl_profile ();
> - clear_log_links ();
> clear_bb_flags ();
> new_direct_jump_p |= purge_all_dead_edges ();
> delete_noop_moves ();
>
> /* Clean up. */
> + obstack_free (&insn_link_obstack, NULL);
> free (uid_log_links);
> free (uid_insn_cost);
> VEC_free (reg_stat_type, heap, reg_stat);
> @@ -1556,13 +1563,11 @@ set_nonzero_bits_and_sign_copies (rtx x, const_rtx
> set, void *data)
> && !REGNO_REG_SET_P (DF_LR_IN (BLOCK_FOR_INSN (insn)),
> REGNO (x)))
> {
> - rtx link;
> + struct insn_link *link;
>
> - for (link = LOG_LINKS (insn); link; link = XEXP (link, 1))
> - {
> - if (dead_or_set_p (XEXP (link, 0), x))
> - break;
> - }
> + FOR_EACH_LOG_LINK (link, insn)
> + if (dead_or_set_p (link->insn, x))
> + break;
> if (!link)
> {
> rsp->nonzero_bits = GET_MODE_MASK (GET_MODE (x));
> @@ -2248,7 +2253,7 @@ adjust_for_new_dest (rtx insn)
> /* The new insn will have a destination that was previously the destination
> of an insn just above it. Call distribute_links to make a LOG_LINK from
> the next use of that destination. */
> - distribute_links (gen_rtx_INSN_LIST (VOIDmode, insn, NULL_RTX));
> + distribute_links (alloc_insn_link (insn, NULL));
>
> df_insn_rescan (insn);
> }
> @@ -2547,7 +2552,7 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
> *new_direct_jump_p)
>
> int maxreg;
> rtx temp;
> - rtx link;
> + struct insn_link *link;
> rtx other_pat = 0;
> rtx new_other_notes;
> int i;
> @@ -3929,7 +3934,7 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
> *new_direct_jump_p)
> if (swap_i2i3)
> {
> rtx insn;
> - rtx link;
> + struct insn_link *link;
> rtx ni2dest;
>
> /* I3 now uses what used to be its destination and which is now
> @@ -3959,10 +3964,9 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
> *new_direct_jump_p)
> {
> if (INSN_P (insn) && reg_referenced_p (ni2dest, PATTERN (insn)))
> {
> - for (link = LOG_LINKS (insn); link;
> - link = XEXP (link, 1))
> - if (XEXP (link, 0) == i3)
> - XEXP (link, 0) = i1;
> + FOR_EACH_LOG_LINK (link, insn)
> + if (link->insn == i3)
> + link->insn = i1;
>
> break;
> }
> @@ -3971,7 +3975,7 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
> *new_direct_jump_p)
>
> {
> rtx i3notes, i2notes, i1notes = 0, i0notes = 0;
> - rtx i3links, i2links, i1links = 0, i0links = 0;
> + struct insn_link *i3links, *i2links, *i1links = 0, *i0links = 0;
> rtx midnotes = 0;
> int from_luid;
> /* Compute which registers we expect to eliminate. newi2pat may be
> setting
> @@ -4074,9 +4078,9 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
> *new_direct_jump_p)
> || BB_HEAD (this_basic_block) != temp);
> temp = NEXT_INSN (temp))
> if (temp != i3 && INSN_P (temp))
> - for (link = LOG_LINKS (temp); link; link = XEXP (link, 1))
> - if (XEXP (link, 0) == i2)
> - XEXP (link, 0) = i3;
> + FOR_EACH_LOG_LINK (link, temp)
> + if (link->insn == i2)
> + link->insn = i3;
>
> if (i3notes)
> {
> @@ -4090,9 +4094,9 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
> *new_direct_jump_p)
> i2notes = 0;
> }
>
> - LOG_LINKS (i3) = 0;
> + LOG_LINKS (i3) = NULL;
> REG_NOTES (i3) = 0;
> - LOG_LINKS (i2) = 0;
> + LOG_LINKS (i2) = NULL;
> REG_NOTES (i2) = 0;
>
> if (newi2pat)
> @@ -4111,7 +4115,7 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
> *new_direct_jump_p)
>
> if (i1)
> {
> - LOG_LINKS (i1) = 0;
> + LOG_LINKS (i1) = NULL;
> REG_NOTES (i1) = 0;
> if (MAY_HAVE_DEBUG_INSNS)
> propagate_for_debug (i1, i3, i1dest, i1src);
> @@ -4120,7 +4124,7 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
> *new_direct_jump_p)
>
> if (i0)
> {
> - LOG_LINKS (i0) = 0;
> + LOG_LINKS (i0) = NULL;
> REG_NOTES (i0) = 0;
> if (MAY_HAVE_DEBUG_INSNS)
> propagate_for_debug (i0, i3, i0dest, i0src);
> @@ -4231,7 +4235,8 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
> *new_direct_jump_p)
>
> if (REG_P (i2dest))
> {
> - rtx link, i2_insn = 0, i2_val = 0, set;
> + struct insn_link *link;
> + rtx i2_insn = 0, i2_val = 0, set;
>
> /* The insn that used to set this register doesn't exist, and
> this life of the register may not exist either. See if one of
> @@ -4240,10 +4245,10 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
> *new_direct_jump_p)
> this and I2 set the register to a value that depended on its old
> contents, we will get confused. If this insn is used, thing
> will be set correctly in combine_instructions. */
> - for (link = LOG_LINKS (i3); link; link = XEXP (link, 1))
> - if ((set = single_set (XEXP (link, 0))) != 0
> + FOR_EACH_LOG_LINK (link, i3)
> + if ((set = single_set (link->insn)) != 0
> && rtx_equal_p (i2dest, SET_DEST (set)))
> - i2_insn = XEXP (link, 0), i2_val = SET_SRC (set);
> + i2_insn = link->insn, i2_val = SET_SRC (set);
>
> record_value_for_reg (i2dest, i2_insn, i2_val);
>
> @@ -4257,12 +4262,13 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
> *new_direct_jump_p)
>
> if (i1 && REG_P (i1dest))
> {
> - rtx link, i1_insn = 0, i1_val = 0, set;
> + struct insn_link *link;
> + rtx i1_insn = 0, i1_val = 0, set;
>
> - for (link = LOG_LINKS (i3); link; link = XEXP (link, 1))
> - if ((set = single_set (XEXP (link, 0))) != 0
> + FOR_EACH_LOG_LINK (link, i3)
> + if ((set = single_set (link->insn)) != 0
> && rtx_equal_p (i1dest, SET_DEST (set)))
> - i1_insn = XEXP (link, 0), i1_val = SET_SRC (set);
> + i1_insn = link->insn, i1_val = SET_SRC (set);
>
> record_value_for_reg (i1dest, i1_insn, i1_val);
>
> @@ -4272,12 +4278,13 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
> *new_direct_jump_p)
>
> if (i0 && REG_P (i0dest))
> {
> - rtx link, i0_insn = 0, i0_val = 0, set;
> + struct insn_link *link;
> + rtx i0_insn = 0, i0_val = 0, set;
>
> - for (link = LOG_LINKS (i3); link; link = XEXP (link, 1))
> - if ((set = single_set (XEXP (link, 0))) != 0
> + FOR_EACH_LOG_LINK (link, i3)
> + if ((set = single_set (link->insn)) != 0
> && rtx_equal_p (i0dest, SET_DEST (set)))
> - i0_insn = XEXP (link, 0), i0_val = SET_SRC (set);
> + i0_insn = link->insn, i0_val = SET_SRC (set);
>
> record_value_for_reg (i0dest, i0_insn, i0_val);
>
> @@ -12349,7 +12356,8 @@ record_dead_and_set_regs (rtx insn)
> static void
> record_promoted_value (rtx insn, rtx subreg)
> {
> - rtx links, set;
> + struct insn_link *links;
> + rtx set;
> unsigned int regno = REGNO (SUBREG_REG (subreg));
> enum machine_mode mode = GET_MODE (subreg);
>
> @@ -12360,14 +12368,14 @@ record_promoted_value (rtx insn, rtx subreg)
> {
> reg_stat_type *rsp;
>
> - insn = XEXP (links, 0);
> + insn = links->insn;
> set = single_set (insn);
>
> if (! set || !REG_P (SET_DEST (set))
> || REGNO (SET_DEST (set)) != regno
> || GET_MODE (SET_DEST (set)) != GET_MODE (SUBREG_REG (subreg)))
> {
> - links = XEXP (links, 1);
> + links = links->next;
> continue;
> }
>
> @@ -13500,8 +13508,8 @@ distribute_notes (rtx notes, rtx from_insn, rtx i3,
> rtx i2, rtx elim_i2,
> && DF_INSN_LUID (from_insn) > DF_INSN_LUID (i2)
> && reg_referenced_p (XEXP (note, 0), PATTERN (i2)))
> {
> - rtx links = LOG_LINKS (place);
> - LOG_LINKS (place) = 0;
> + struct insn_link *links = LOG_LINKS (place);
> + LOG_LINKS (place) = NULL;
> distribute_links (links);
> }
> break;
> @@ -13632,9 +13640,9 @@ distribute_notes (rtx notes, rtx from_insn, rtx i3,
> rtx i2, rtx elim_i2,
> pointing at I3 when I3's destination is changed. */
>
> static void
> -distribute_links (rtx links)
> +distribute_links (struct insn_link *links)
> {
> - rtx link, next_link;
> + struct insn_link *link, *next_link;
>
> for (link = links; link; link = next_link)
> {
> @@ -13642,7 +13650,7 @@ distribute_links (rtx links)
> rtx insn;
> rtx set, reg;
>
> - next_link = XEXP (link, 1);
> + next_link = link->next;
>
> /* If the insn that this link points to is a NOTE or isn't a single
> set, ignore it. In the latter case, it isn't clear what we
> @@ -13655,8 +13663,8 @@ distribute_links (rtx links)
> replace I3, I2, and I1 by I3 and I2. But in that case the
> destination of I2 also remains unchanged. */
>
> - if (NOTE_P (XEXP (link, 0))
> - || (set = single_set (XEXP (link, 0))) == 0)
> + if (NOTE_P (link->insn)
> + || (set = single_set (link->insn)) == 0)
> continue;
>
> reg = SET_DEST (set);
> @@ -13673,7 +13681,7 @@ distribute_links (rtx links)
> I3 to I2. Also note that not much searching is typically done here
> since most links don't point very far away. */
>
> - for (insn = NEXT_INSN (XEXP (link, 0));
> + for (insn = NEXT_INSN (link->insn);
> (insn && (this_basic_block->next_bb == EXIT_BLOCK_PTR
> || BB_HEAD (this_basic_block->next_bb) != insn));
> insn = NEXT_INSN (insn))
> @@ -13699,15 +13707,15 @@ distribute_links (rtx links)
>
> if (place)
> {
> - rtx link2;
> + struct insn_link *link2;
>
> - for (link2 = LOG_LINKS (place); link2; link2 = XEXP (link2, 1))
> - if (XEXP (link2, 0) == XEXP (link, 0))
> + FOR_EACH_LOG_LINK (link2, place)
> + if (link2->insn == link->insn)
> break;
>
> - if (link2 == 0)
> + if (link2 == NULL)
> {
> - XEXP (link, 1) = LOG_LINKS (place);
> + link->next = LOG_LINKS (place);
> LOG_LINKS (place) = link;
>
> /* Set added_links_insn to the earliest insn we added a
>
