#include "tree-pass.h"
#include "df.h"
#include "target.h"
+#include "emit-rtl.h"
+#include "regrename.h"
/* This file implements the RTL register renaming pass of the compiler. It is
a semi-local pass whose goal is to maximize the usage of the register file
1. Local def/use chains are built: within each basic block, chains are
opened and closed; if a chain isn't closed at the end of the block,
- it is dropped.
+ it is dropped. We pre-open chains if we have already examined a
+ predecessor block and found chains live at the end which match
+ live registers at the start of the new block.
- 2. For each chain, the set of possible renaming registers is computed.
+ 2. We try to combine the local chains across basic block boundaries by
+ comparing chains that were open at the start or end of a block to
+ those in successor/predecessor blocks.
+
+ 3. For each chain, the set of possible renaming registers is computed.
This takes into account the renaming of previously processed chains.
Optionally, a preferred class is computed for the renaming register.
- 3. The best renaming register is computed for the chain in the above set,
+ 4. The best renaming register is computed for the chain in the above set,
using a round-robin allocation. If a preferred class exists, then the
round-robin allocation is done within the class first, if possible.
The round-robin allocation of renaming registers itself is global.
- 4. If a renaming register has been found, it is substituted in the chain.
+ 5. If a renaming register has been found, it is substituted in the chain.
Targets can parameterize the pass by specifying a preferred class for the
renaming register for a given (super)class of registers to be renamed. */
#error "Use a different bitmap implementation for untracked_operands."
#endif
-/* We keep linked lists of DU_HEAD structures, each of which describes
- a chain of occurrences of a reg. */
-struct du_head
-{
- /* The next chain. */
- struct du_head *next_chain;
- /* The first and last elements of this chain. */
- struct du_chain *first, *last;
- /* Describes the register being tracked. */
- unsigned regno, nregs;
-
- /* A unique id to be used as an index into the conflicts bitmaps. */
- unsigned id;
- /* A bitmap to record conflicts with other chains. */
- bitmap_head conflicts;
- /* Conflicts with untracked hard registers. */
- HARD_REG_SET hard_conflicts;
-
- /* Nonzero if the chain crosses a call. */
- unsigned int need_caller_save_reg:1;
- /* Nonzero if the register is used in a way that prevents renaming,
- such as the SET_DEST of a CALL_INSN or an asm operand that used
- to be a hard register. */
- unsigned int cannot_rename:1;
-};
-
-/* This struct describes a single occurrence of a register. */
-struct du_chain
-{
- /* Links to the next occurrence of the register. */
- struct du_chain *next_use;
-
- /* The insn where the register appears. */
- rtx insn;
- /* The location inside the insn. */
- rtx *loc;
- /* The register class required by the insn at this location. */
- ENUM_BITFIELD(reg_class) cl : 16;
-};
-
enum scan_actions
{
terminate_write,
static struct obstack rename_obstack;
-static void do_replace (struct du_head *, int);
-static void scan_rtx_reg (rtx, rtx *, enum reg_class,
- enum scan_actions, enum op_type);
-static void scan_rtx_address (rtx, rtx *, enum reg_class,
- enum scan_actions, enum machine_mode);
+/* If nonnull, the code calling into the register renamer requested
+ information about insn operands, and we store it here. */
+VEC(insn_rr_info, heap) *insn_rr;
+
static void scan_rtx (rtx, rtx *, enum reg_class, enum scan_actions,
enum op_type);
-static struct du_head *build_def_use (basic_block);
-static void dump_def_use_chain (struct du_head *);
-
-typedef struct du_head *du_head_p;
-DEF_VEC_P (du_head_p);
-DEF_VEC_ALLOC_P (du_head_p, heap);
+static bool build_def_use (basic_block);
/* The id to be given to the next opened chain. */
static unsigned current_id;
/* A mapping of unique id numbers to chains. */
static VEC(du_head_p, heap) *id_to_chain;
-/* List of currently open chains, and closed chains that can be renamed. */
+/* List of currently open chains. */
static struct du_head *open_chains;
-static struct du_head *closed_chains;
/* Bitmap of open chains. The bits set always match the list found in
open_chains. */
between this and live_in_chains is empty. */
static HARD_REG_SET live_hard_regs;
-/* Dump all def/use chains in CHAINS to DUMP_FILE. */
+/* Set while scanning RTL if INSN_RR is nonnull, i.e. if the current analysis
+ is for a caller that requires operand data. Used in
+ record_operand_use. */
+static operand_rr_info *cur_operand;
+
+/* Return the chain corresponding to id number ID. Take into account that
+ chains may have been merged. */
+du_head_p
+regrename_chain_from_id (unsigned int id)
+{
+ du_head_p first_chain = VEC_index (du_head_p, id_to_chain, id);
+ du_head_p chain = first_chain;
+ while (chain->id != id)
+ {
+ id = chain->id;
+ chain = VEC_index (du_head_p, id_to_chain, id);
+ }
+ first_chain->id = id;
+ return chain;
+}
+
+/* Dump all def/use chains, starting at id FROM. */
static void
-dump_def_use_chain (struct du_head *head)
+dump_def_use_chain (int from)
{
- while (head)
+ du_head_p head;
+ int i;
+ FOR_EACH_VEC_ELT_FROM (du_head_p, id_to_chain, i, head, from)
{
struct du_chain *this_du = head->first;
+
fprintf (dump_file, "Register %s (%d):",
reg_names[head->regno], head->nregs);
while (this_du)
VEC_free (du_head_p, heap, id_to_chain);
}
+/* Walk all chains starting with CHAINS and record that they conflict with
+ another chain whose id is ID. */
+
+static void
+mark_conflict (struct du_head *chains, unsigned id)
+{
+ while (chains)
+ {
+ bitmap_set_bit (&chains->conflicts, id);
+ chains = chains->next_chain;
+ }
+}
+
+/* Examine cur_operand, and if it is nonnull, record information about the
+ use THIS_DU which is part of the chain HEAD. */
+
+static void
+record_operand_use (struct du_head *head, struct du_chain *this_du)
+{
+ if (cur_operand == NULL)
+ return;
+ gcc_assert (cur_operand->n_chains < MAX_REGS_PER_ADDRESS);
+ cur_operand->heads[cur_operand->n_chains] = head;
+ cur_operand->chains[cur_operand->n_chains++] = this_du;
+}
+
+/* Create a new chain for THIS_NREGS registers starting at THIS_REGNO,
+ and record its occurrence in *LOC, which is being written to in INSN.
+ This access requires a register of class CL. */
+
+static du_head_p
+create_new_chain (unsigned this_regno, unsigned this_nregs, rtx *loc,
+ rtx insn, enum reg_class cl)
+{
+ struct du_head *head = XOBNEW (&rename_obstack, struct du_head);
+ struct du_chain *this_du;
+ int nregs;
+
+ head->next_chain = open_chains;
+ head->regno = this_regno;
+ head->nregs = this_nregs;
+ head->need_caller_save_reg = 0;
+ head->cannot_rename = 0;
+
+ VEC_safe_push (du_head_p, heap, id_to_chain, head);
+ head->id = current_id++;
+
+ bitmap_initialize (&head->conflicts, &bitmap_default_obstack);
+ bitmap_copy (&head->conflicts, &open_chains_set);
+ mark_conflict (open_chains, head->id);
+
+ /* Since we're tracking this as a chain now, remove it from the
+ list of conflicting live hard registers and track it in
+ live_in_chains instead. */
+ nregs = head->nregs;
+ while (nregs-- > 0)
+ {
+ SET_HARD_REG_BIT (live_in_chains, head->regno + nregs);
+ CLEAR_HARD_REG_BIT (live_hard_regs, head->regno + nregs);
+ }
+
+ COPY_HARD_REG_SET (head->hard_conflicts, live_hard_regs);
+ bitmap_set_bit (&open_chains_set, head->id);
+
+ open_chains = head;
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "Creating chain %s (%d)",
+ reg_names[head->regno], head->id);
+ if (insn != NULL_RTX)
+ fprintf (dump_file, " at insn %d", INSN_UID (insn));
+ fprintf (dump_file, "\n");
+ }
+
+ if (insn == NULL_RTX)
+ {
+ head->first = head->last = NULL;
+ return head;
+ }
+
+ this_du = XOBNEW (&rename_obstack, struct du_chain);
+ head->first = head->last = this_du;
+
+ this_du->next_use = 0;
+ this_du->loc = loc;
+ this_du->insn = insn;
+ this_du->cl = cl;
+ record_operand_use (head, this_du);
+ return head;
+}
+
/* For a def-use chain HEAD, find which registers overlap its lifetime and
set the corresponding bits in *PSET. */
IOR_HARD_REG_SET (*pset, head->hard_conflicts);
EXECUTE_IF_SET_IN_BITMAP (&head->conflicts, 0, i, bi)
{
- du_head_p other = VEC_index (du_head_p, id_to_chain, i);
+ du_head_p other = regrename_chain_from_id (i);
unsigned j = other->nregs;
+ gcc_assert (other != head);
while (j-- > 0)
SET_HARD_REG_BIT (*pset, other->regno + j);
}
return true;
}
-/* Process the closed chains starting with ALL_CHAINS and rename
- registers if possible. */
+/* For the chain THIS_HEAD, compute and return the best register to
+ rename to. SUPER_CLASS is the superunion of register classes in
+ the chain. UNAVAILABLE is a set of registers that cannot be used.
+ OLD_REG is the register currently used for the chain. */
+
+int
+find_best_rename_reg (du_head_p this_head, enum reg_class super_class,
+ HARD_REG_SET *unavailable, int old_reg)
+{
+ bool has_preferred_class;
+ enum reg_class preferred_class;
+ int pass;
+ int best_new_reg = old_reg;
+
+ /* Further narrow the set of registers we can use for renaming.
+ If the chain needs a call-saved register, mark the call-used
+ registers as unavailable. */
+ if (this_head->need_caller_save_reg)
+ IOR_HARD_REG_SET (*unavailable, call_used_reg_set);
+
+ /* Mark registers that overlap this chain's lifetime as unavailable. */
+ merge_overlapping_regs (unavailable, this_head);
+
+ /* Compute preferred rename class of super union of all the classes
+ in the chain. */
+ preferred_class
+ = (enum reg_class) targetm.preferred_rename_class (super_class);
+
+ /* If PREFERRED_CLASS is not NO_REGS, we iterate in the first pass
+ over registers that belong to PREFERRED_CLASS and try to find the
+ best register within the class. If that failed, we iterate in
+ the second pass over registers that don't belong to the class.
+ If PREFERRED_CLASS is NO_REGS, we iterate over all registers in
+ ascending order without any preference. */
+ has_preferred_class = (preferred_class != NO_REGS);
+ for (pass = (has_preferred_class ? 0 : 1); pass < 2; pass++)
+ {
+ int new_reg;
+ for (new_reg = 0; new_reg < FIRST_PSEUDO_REGISTER; new_reg++)
+ {
+ if (has_preferred_class
+ && (pass == 0)
+ != TEST_HARD_REG_BIT (reg_class_contents[preferred_class],
+ new_reg))
+ continue;
+
+ /* In the first pass, we force the renaming of registers that
+ don't belong to PREFERRED_CLASS to registers that do, even
+ though the latters were used not very long ago. */
+ if (check_new_reg_p (old_reg, new_reg, this_head,
+ *unavailable)
+ && ((pass == 0
+ && !TEST_HARD_REG_BIT (reg_class_contents[preferred_class],
+ best_new_reg))
+ || tick[best_new_reg] > tick[new_reg]))
+ best_new_reg = new_reg;
+ }
+ if (pass == 0 && best_new_reg != old_reg)
+ break;
+ }
+ return best_new_reg;
+}
+
+/* Perform register renaming on the current function. */
static void
-rename_chains (du_head_p all_chains)
+rename_chains (void)
{
HARD_REG_SET unavailable;
+ du_head_p this_head;
+ int i;
+
+ memset (tick, 0, sizeof tick);
CLEAR_HARD_REG_SET (unavailable);
/* Don't clobber traceback for noreturn functions. */
#endif
}
- while (all_chains)
+ FOR_EACH_VEC_ELT (du_head_p, id_to_chain, i, this_head)
{
- int new_reg, best_new_reg, best_nregs;
+ int best_new_reg;
int n_uses;
- struct du_head *this_head = all_chains;
struct du_chain *tmp;
HARD_REG_SET this_unavailable;
int reg = this_head->regno;
- int pass;
enum reg_class super_class = NO_REGS;
- enum reg_class preferred_class;
- bool has_preferred_class;
-
- all_chains = this_head->next_chain;
if (this_head->cannot_rename)
continue;
- best_new_reg = reg;
- best_nregs = this_head->nregs;
-
if (fixed_regs[reg] || global_regs[reg]
#if !HARD_FRAME_POINTER_IS_FRAME_POINTER
|| (frame_pointer_needed && reg == HARD_FRAME_POINTER_REGNUM)
if (n_uses < 2)
continue;
- /* Further narrow the set of registers we can use for renaming.
- If the chain needs a call-saved register, mark the call-used
- registers as unavailable. */
- if (this_head->need_caller_save_reg)
- IOR_HARD_REG_SET (this_unavailable, call_used_reg_set);
-
- /* And mark registers that overlap its lifetime as unavailable. */
- merge_overlapping_regs (&this_unavailable, this_head);
-
- /* Compute preferred rename class of super union of all the classes
- in the chain. */
- preferred_class
- = (enum reg_class) targetm.preferred_rename_class (super_class);
-
- /* If PREFERRED_CLASS is not NO_REGS, we iterate in the first pass
- over registers that belong to PREFERRED_CLASS and try to find the
- best register within the class. If that failed, we iterate in
- the second pass over registers that don't belong to the class.
- If PREFERRED_CLASS is NO_REGS, we iterate over all registers in
- ascending order without any preference. */
- has_preferred_class = (preferred_class != NO_REGS);
- for (pass = (has_preferred_class ? 0 : 1); pass < 2; pass++)
- {
- for (new_reg = 0; new_reg < FIRST_PSEUDO_REGISTER; new_reg++)
- {
- if (has_preferred_class
- && ((pass == 0) != TEST_HARD_REG_BIT
- (reg_class_contents[preferred_class], new_reg)))
- continue;
-
- /* In the first pass, we force the renaming of registers that
- don't belong to PREFERRED_CLASS to registers that do, even
- though the latters were used not very long ago. */
- if (check_new_reg_p (reg, new_reg, this_head,
- this_unavailable)
- && ((pass == 0
- && (!TEST_HARD_REG_BIT
- (reg_class_contents[preferred_class],
- best_new_reg)))
- || tick[best_new_reg] > tick[new_reg]))
- {
- enum machine_mode mode
- = GET_MODE (*this_head->first->loc);
- best_new_reg = new_reg;
- best_nregs = hard_regno_nregs[new_reg][mode];
- }
- }
- if (pass == 0 && best_new_reg != reg)
- break;
- }
+ best_new_reg = find_best_rename_reg (this_head, super_class,
+ &this_unavailable, reg);
if (dump_file)
{
if (dump_file)
fprintf (dump_file, ", renamed as %s\n", reg_names[best_new_reg]);
- do_replace (this_head, best_new_reg);
- this_head->regno = best_new_reg;
- this_head->nregs = best_nregs;
+ regrename_do_replace (this_head, best_new_reg);
tick[best_new_reg] = ++this_tick;
df_set_regs_ever_live (best_new_reg, true);
}
}
-/* Perform register renaming on the current function. */
+/* A structure to record information for each hard register at the start of
+ a basic block. */
+struct incoming_reg_info {
+ /* Holds the number of registers used in the chain that gave us information
+ about this register. Zero means no information known yet, while a
+ negative value is used for something that is part of, but not the first
+ register in a multi-register value. */
+ int nregs;
+ /* Set to true if we have accesses that conflict in the number of registers
+ used. */
+ bool unusable;
+};
-static unsigned int
-regrename_optimize (void)
+/* A structure recording information about each basic block. It is saved
+ and restored around basic block boundaries.
+ A pointer to such a structure is stored in each basic block's aux field
+ during regrename_analyze, except for blocks we know can't be optimized
+ (such as entry and exit blocks). */
+struct bb_rename_info
{
+ /* The basic block corresponding to this structure. */
basic_block bb;
- char *first_obj;
+ /* Copies of the global information. */
+ bitmap_head open_chains_set;
+ bitmap_head incoming_open_chains_set;
+ struct incoming_reg_info incoming[FIRST_PSEUDO_REGISTER];
+};
- df_set_flags (DF_LR_RUN_DCE);
- df_note_add_problem ();
- df_analyze ();
- df_set_flags (DF_DEFER_INSN_RESCAN);
+/* Initialize a rename_info structure P for basic block BB, which starts a new
+ scan. */
+static void
+init_rename_info (struct bb_rename_info *p, basic_block bb)
+{
+ int i;
+ df_ref *def_rec;
+ HARD_REG_SET start_chains_set;
- memset (tick, 0, sizeof tick);
+ p->bb = bb;
+ bitmap_initialize (&p->open_chains_set, &bitmap_default_obstack);
+ bitmap_initialize (&p->incoming_open_chains_set, &bitmap_default_obstack);
- gcc_obstack_init (&rename_obstack);
- first_obj = XOBNEWVAR (&rename_obstack, char, 0);
+ open_chains = NULL;
+ bitmap_clear (&open_chains_set);
+ CLEAR_HARD_REG_SET (live_in_chains);
+ REG_SET_TO_HARD_REG_SET (live_hard_regs, df_get_live_in (bb));
+ for (def_rec = df_get_artificial_defs (bb->index); *def_rec; def_rec++)
+ {
+ df_ref def = *def_rec;
+ if (DF_REF_FLAGS (def) & DF_REF_AT_TOP)
+ SET_HARD_REG_BIT (live_hard_regs, DF_REF_REGNO (def));
+ }
+
+ /* Open chains based on information from (at least one) predecessor
+ block. This gives us a chance later on to combine chains across
+ basic block boundaries. Inconsistencies (in access sizes) will
+ be caught normally and dealt with conservatively by disabling the
+ chain for renaming, and there is no risk of losing optimization
+ opportunities by opening chains either: if we did not open the
+ chains, we'd have to track the live register as a hard reg, and
+ we'd be unable to rename it in any case. */
+ CLEAR_HARD_REG_SET (start_chains_set);
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ {
+ struct incoming_reg_info *iri = p->incoming + i;
+ if (iri->nregs > 0 && !iri->unusable
+ && range_in_hard_reg_set_p (live_hard_regs, i, iri->nregs))
+ {
+ SET_HARD_REG_BIT (start_chains_set, i);
+ remove_range_from_hard_reg_set (&live_hard_regs, i, iri->nregs);
+ }
+ }
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ {
+ struct incoming_reg_info *iri = p->incoming + i;
+ if (TEST_HARD_REG_BIT (start_chains_set, i))
+ {
+ du_head_p chain;
+ if (dump_file)
+ fprintf (dump_file, "opening incoming chain\n");
+ chain = create_new_chain (i, iri->nregs, NULL, NULL_RTX, NO_REGS);
+ bitmap_set_bit (&p->incoming_open_chains_set, chain->id);
+ }
+ }
+}
+
+/* Record in RI that the block corresponding to it has an incoming
+ live value, described by CHAIN. */
+static void
+set_incoming_from_chain (struct bb_rename_info *ri, du_head_p chain)
+{
+ int i;
+ int incoming_nregs = ri->incoming[chain->regno].nregs;
+ int nregs;
+
+ /* If we've recorded the same information before, everything is fine. */
+ if (incoming_nregs == chain->nregs)
+ {
+ if (dump_file)
+ fprintf (dump_file, "reg %d/%d already recorded\n",
+ chain->regno, chain->nregs);
+ return;
+ }
+
+ /* If we have no information for any of the involved registers, update
+ the incoming array. */
+ nregs = chain->nregs;
+ while (nregs-- > 0)
+ if (ri->incoming[chain->regno + nregs].nregs != 0
+ || ri->incoming[chain->regno + nregs].unusable)
+ break;
+ if (nregs < 0)
+ {
+ nregs = chain->nregs;
+ ri->incoming[chain->regno].nregs = nregs;
+ while (nregs-- > 1)
+ ri->incoming[chain->regno + nregs].nregs = -nregs;
+ if (dump_file)
+ fprintf (dump_file, "recorded reg %d/%d\n",
+ chain->regno, chain->nregs);
+ return;
+ }
+
+ /* There must be some kind of conflict. Prevent both the old and
+ new ranges from being used. */
+ if (incoming_nregs < 0)
+ ri->incoming[chain->regno + incoming_nregs].unusable = true;
+ for (i = 0; i < chain->nregs; i++)
+ ri->incoming[chain->regno + i].unusable = true;
+}
+
+/* Merge the two chains C1 and C2 so that all conflict information is
+ recorded and C1, and the id of C2 is changed to that of C1. */
+static void
+merge_chains (du_head_p c1, du_head_p c2)
+{
+ if (c1 == c2)
+ return;
+
+ if (c2->first != NULL)
+ {
+ if (c1->first == NULL)
+ c1->first = c2->first;
+ else
+ c1->last->next_use = c2->first;
+ c1->last = c2->last;
+ }
+
+ c2->first = c2->last = NULL;
+ c2->id = c1->id;
+
+ IOR_HARD_REG_SET (c1->hard_conflicts, c2->hard_conflicts);
+ bitmap_ior_into (&c1->conflicts, &c2->conflicts);
+
+ c1->need_caller_save_reg |= c2->need_caller_save_reg;
+ c1->cannot_rename |= c2->cannot_rename;
+}
+
+/* Analyze the current function and build chains for renaming. */
+
+void
+regrename_analyze (bitmap bb_mask)
+{
+ struct bb_rename_info *rename_info;
+ int i;
+ basic_block bb;
+ int n_bbs;
+ int *inverse_postorder;
+
+ inverse_postorder = XNEWVEC (int, last_basic_block);
+ n_bbs = pre_and_rev_post_order_compute (NULL, inverse_postorder, false);
+
+ /* Gather some information about the blocks in this function. */
+ rename_info = XCNEWVEC (struct bb_rename_info, n_basic_blocks);
+ i = 0;
FOR_EACH_BB (bb)
{
- struct du_head *all_chains = 0;
+ struct bb_rename_info *ri = rename_info + i;
+ ri->bb = bb;
+ if (bb_mask != NULL && !bitmap_bit_p (bb_mask, bb->index))
+ bb->aux = NULL;
+ else
+ bb->aux = ri;
+ i++;
+ }
+
+ current_id = 0;
+ id_to_chain = VEC_alloc (du_head_p, heap, 0);
+ bitmap_initialize (&open_chains_set, &bitmap_default_obstack);
- id_to_chain = VEC_alloc (du_head_p, heap, 0);
+ /* The order in which we visit blocks ensures that whenever
+ possible, we only process a block after at least one of its
+ predecessors, which provides a "seeding" effect to make the logic
+ in set_incoming_from_chain and init_rename_info useful. */
+
+ for (i = 0; i < n_bbs; i++)
+ {
+ basic_block bb1 = BASIC_BLOCK (inverse_postorder[i]);
+ struct bb_rename_info *this_info;
+ bool success;
+ edge e;
+ edge_iterator ei;
+ int old_length = VEC_length (du_head_p, id_to_chain);
+
+ this_info = (struct bb_rename_info *) bb1->aux;
+ if (this_info == NULL)
+ continue;
if (dump_file)
- fprintf (dump_file, "\nBasic block %d:\n", bb->index);
+ fprintf (dump_file, "\nprocessing block %d:\n", bb1->index);
- all_chains = build_def_use (bb);
+ init_rename_info (this_info, bb1);
+
+ success = build_def_use (bb1);
+ if (!success)
+ {
+ if (dump_file)
+ fprintf (dump_file, "failed\n");
+ bb1->aux = NULL;
+ VEC_truncate (du_head_p, id_to_chain, old_length);
+ current_id = old_length;
+ bitmap_clear (&this_info->incoming_open_chains_set);
+ open_chains = NULL;
+ if (insn_rr != NULL)
+ {
+ rtx insn;
+ FOR_BB_INSNS (bb1, insn)
+ {
+ insn_rr_info *p = VEC_index (insn_rr_info, insn_rr,
+ INSN_UID (insn));
+ p->op_info = NULL;
+ }
+ }
+ continue;
+ }
if (dump_file)
- dump_def_use_chain (all_chains);
+ dump_def_use_chain (old_length);
+ bitmap_copy (&this_info->open_chains_set, &open_chains_set);
+
+ /* Add successor blocks to the worklist if necessary, and record
+ data about our own open chains at the end of this block, which
+ will be used to pre-open chains when processing the successors. */
+ FOR_EACH_EDGE (e, ei, bb1->succs)
+ {
+ struct bb_rename_info *dest_ri;
+ struct du_head *chain;
- rename_chains (all_chains);
+ if (dump_file)
+ fprintf (dump_file, "successor block %d\n", e->dest->index);
- free_chain_data ();
- obstack_free (&rename_obstack, first_obj);
+ if (e->flags & (EDGE_EH | EDGE_ABNORMAL))
+ continue;
+ dest_ri = (struct bb_rename_info *)e->dest->aux;
+ if (dest_ri == NULL)
+ continue;
+ for (chain = open_chains; chain; chain = chain->next_chain)
+ set_incoming_from_chain (dest_ri, chain);
+ }
}
- obstack_free (&rename_obstack, NULL);
+ free (inverse_postorder);
- if (dump_file)
- fputc ('\n', dump_file);
+ /* Now, combine the chains data we have gathered across basic block
+ boundaries.
- return 0;
+ For every basic block, there may be chains open at the start, or at the
+ end. Rather than exclude them from renaming, we look for open chains
+ with matching registers at the other side of the CFG edge.
+
+ For a given chain using register R, open at the start of block B, we
+ must find an open chain using R on the other side of every edge leading
+ to B, if the register is live across this edge. In the code below,
+ N_PREDS_USED counts the number of edges where the register is live, and
+ N_PREDS_JOINED counts those where we found an appropriate chain for
+ joining.
+
+ We perform the analysis for both incoming and outgoing edges, but we
+ only need to merge once (in the second part, after verifying outgoing
+ edges). */
+ FOR_EACH_BB (bb)
+ {
+ struct bb_rename_info *bb_ri = (struct bb_rename_info *) bb->aux;
+ unsigned j;
+ bitmap_iterator bi;
+
+ if (bb_ri == NULL)
+ continue;
+
+ if (dump_file)
+ fprintf (dump_file, "processing bb %d in edges\n", bb->index);
+
+ EXECUTE_IF_SET_IN_BITMAP (&bb_ri->incoming_open_chains_set, 0, j, bi)
+ {
+ edge e;
+ edge_iterator ei;
+ struct du_head *chain = regrename_chain_from_id (j);
+ int n_preds_used = 0, n_preds_joined = 0;
+
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ {
+ struct bb_rename_info *src_ri;
+ unsigned k;
+ bitmap_iterator bi2;
+ HARD_REG_SET live;
+ bool success = false;
+
+ REG_SET_TO_HARD_REG_SET (live, df_get_live_out (e->src));
+ if (!range_overlaps_hard_reg_set_p (live, chain->regno,
+ chain->nregs))
+ continue;
+ n_preds_used++;
+
+ if (e->flags & (EDGE_EH | EDGE_ABNORMAL))
+ continue;
+
+ src_ri = (struct bb_rename_info *)e->src->aux;
+ if (src_ri == NULL)
+ continue;
+
+ EXECUTE_IF_SET_IN_BITMAP (&src_ri->open_chains_set,
+ 0, k, bi2)
+ {
+ struct du_head *outgoing_chain = regrename_chain_from_id (k);
+
+ if (outgoing_chain->regno == chain->regno
+ && outgoing_chain->nregs == chain->nregs)
+ {
+ n_preds_joined++;
+ success = true;
+ break;
+ }
+ }
+ if (!success && dump_file)
+ fprintf (dump_file, "failure to match with pred block %d\n",
+ e->src->index);
+ }
+ if (n_preds_joined < n_preds_used)
+ {
+ if (dump_file)
+ fprintf (dump_file, "cannot rename chain %d\n", j);
+ chain->cannot_rename = 1;
+ }
+ }
+ }
+ FOR_EACH_BB (bb)
+ {
+ struct bb_rename_info *bb_ri = (struct bb_rename_info *) bb->aux;
+ unsigned j;
+ bitmap_iterator bi;
+
+ if (bb_ri == NULL)
+ continue;
+
+ if (dump_file)
+ fprintf (dump_file, "processing bb %d out edges\n", bb->index);
+
+ EXECUTE_IF_SET_IN_BITMAP (&bb_ri->open_chains_set, 0, j, bi)
+ {
+ edge e;
+ edge_iterator ei;
+ struct du_head *chain = regrename_chain_from_id (j);
+ int n_succs_used = 0, n_succs_joined = 0;
+
+ FOR_EACH_EDGE (e, ei, bb->succs)
+ {
+ bool printed = false;
+ struct bb_rename_info *dest_ri;
+ unsigned k;
+ bitmap_iterator bi2;
+ HARD_REG_SET live;
+
+ REG_SET_TO_HARD_REG_SET (live, df_get_live_in (e->dest));
+ if (!range_overlaps_hard_reg_set_p (live, chain->regno,
+ chain->nregs))
+ continue;
+
+ n_succs_used++;
+
+ dest_ri = (struct bb_rename_info *)e->dest->aux;
+ if (dest_ri == NULL)
+ continue;
+
+ EXECUTE_IF_SET_IN_BITMAP (&dest_ri->incoming_open_chains_set,
+ 0, k, bi2)
+ {
+ struct du_head *incoming_chain = regrename_chain_from_id (k);
+
+ if (incoming_chain->regno == chain->regno
+ && incoming_chain->nregs == chain->nregs)
+ {
+ if (dump_file)
+ {
+ if (!printed)
+ fprintf (dump_file,
+ "merging blocks for edge %d -> %d\n",
+ e->src->index, e->dest->index);
+ printed = true;
+ fprintf (dump_file,
+ " merging chains %d (->%d) and %d (->%d) [%s]\n",
+ k, incoming_chain->id, j, chain->id,
+ reg_names[incoming_chain->regno]);
+ }
+
+ merge_chains (chain, incoming_chain);
+ n_succs_joined++;
+ break;
+ }
+ }
+ }
+ if (n_succs_joined < n_succs_used)
+ {
+ if (dump_file)
+ fprintf (dump_file, "cannot rename chain %d\n",
+ j);
+ chain->cannot_rename = 1;
+ }
+ }
+ }
+
+ free (rename_info);
+
+ FOR_EACH_BB (bb)
+ bb->aux = NULL;
}
-static void
-do_replace (struct du_head *head, int reg)
+void
+regrename_do_replace (struct du_head *head, int reg)
{
struct du_chain *chain;
unsigned int base_regno = head->regno;
-
- gcc_assert (! DEBUG_INSN_P (head->first->insn));
+ enum machine_mode mode;
for (chain = head->first; chain; chain = chain->next_use)
{
df_insn_rescan (chain->insn);
}
-}
-
-
-/* Walk all chains starting with CHAINS and record that they conflict with
- another chain whose id is ID. */
-static void
-mark_conflict (struct du_head *chains, unsigned id)
-{
- while (chains)
- {
- bitmap_set_bit (&chains->conflicts, id);
- chains = chains->next_chain;
- }
+ mode = GET_MODE (*head->first->loc);
+ head->regno = reg;
+ head->nregs = hard_regno_nregs[reg][mode];
}
+
/* True if we found a register with a size mismatch, which means that we
can't track its lifetime accurately. If so, we abort the current block
without renaming. */
add_to_hard_reg_set (&chain->hard_conflicts, GET_MODE (x), REGNO (x));
}
-/* Create a new chain for THIS_NREGS registers starting at THIS_REGNO,
- and record its occurrence in *LOC, which is being written to in INSN.
- This access requires a register of class CL. */
-
-static void
-create_new_chain (unsigned this_regno, unsigned this_nregs, rtx *loc,
- rtx insn, enum reg_class cl)
-{
- struct du_head *head = XOBNEW (&rename_obstack, struct du_head);
- struct du_chain *this_du;
- int nregs;
-
- head->next_chain = open_chains;
- open_chains = head;
- head->regno = this_regno;
- head->nregs = this_nregs;
- head->need_caller_save_reg = 0;
- head->cannot_rename = 0;
-
- VEC_safe_push (du_head_p, heap, id_to_chain, head);
- head->id = current_id++;
-
- bitmap_initialize (&head->conflicts, &bitmap_default_obstack);
- bitmap_copy (&head->conflicts, &open_chains_set);
- mark_conflict (open_chains, head->id);
-
- /* Since we're tracking this as a chain now, remove it from the
- list of conflicting live hard registers and track it in
- live_in_chains instead. */
- nregs = head->nregs;
- while (nregs-- > 0)
- {
- SET_HARD_REG_BIT (live_in_chains, head->regno + nregs);
- CLEAR_HARD_REG_BIT (live_hard_regs, head->regno + nregs);
- }
-
- COPY_HARD_REG_SET (head->hard_conflicts, live_hard_regs);
- bitmap_set_bit (&open_chains_set, head->id);
-
- open_chains = head;
-
- if (dump_file)
- {
- fprintf (dump_file, "Creating chain %s (%d)",
- reg_names[head->regno], head->id);
- if (insn != NULL_RTX)
- fprintf (dump_file, " at insn %d", INSN_UID (insn));
- fprintf (dump_file, "\n");
- }
-
- if (insn == NULL_RTX)
- {
- head->first = head->last = NULL;
- return;
- }
-
- this_du = XOBNEW (&rename_obstack, struct du_chain);
- head->first = head->last = this_du;
-
- this_du->next_use = 0;
- this_du->loc = loc;
- this_du->insn = insn;
- this_du->cl = cl;
-}
-
static void
scan_rtx_reg (rtx insn, rtx *loc, enum reg_class cl, enum scan_actions action,
enum op_type type)
rtx x = *loc;
enum machine_mode mode = GET_MODE (x);
unsigned this_regno = REGNO (x);
- unsigned this_nregs = hard_regno_nregs[this_regno][mode];
+ int this_nregs = hard_regno_nregs[this_regno][mode];
if (action == mark_write)
{
head->first = this_du;
else
head->last->next_use = this_du;
+ record_operand_use (head, this_du);
head->last = this_du;
}
/* Avoid adding the same location in a DEBUG_INSN multiple times,
if (subset && !superset)
head->cannot_rename = 1;
- head->next_chain = closed_chains;
- closed_chains = head;
bitmap_clear_bit (&open_chains_set, head->id);
nregs = head->nregs;
static void
scan_rtx_address (rtx insn, rtx *loc, enum reg_class cl,
- enum scan_actions action, enum machine_mode mode)
+ enum scan_actions action, enum machine_mode mode,
+ addr_space_t as)
{
rtx x = *loc;
RTX_CODE code = GET_CODE (x);
unsigned regno0 = REGNO (op0), regno1 = REGNO (op1);
if (REGNO_OK_FOR_INDEX_P (regno1)
- && regno_ok_for_base_p (regno0, mode, PLUS, REG))
+ && regno_ok_for_base_p (regno0, mode, as, PLUS, REG))
index_op = 1;
else if (REGNO_OK_FOR_INDEX_P (regno0)
- && regno_ok_for_base_p (regno1, mode, PLUS, REG))
+ && regno_ok_for_base_p (regno1, mode, as, PLUS, REG))
index_op = 0;
- else if (regno_ok_for_base_p (regno0, mode, PLUS, REG)
+ else if (regno_ok_for_base_p (regno0, mode, as, PLUS, REG)
|| REGNO_OK_FOR_INDEX_P (regno1))
index_op = 1;
- else if (regno_ok_for_base_p (regno1, mode, PLUS, REG))
+ else if (regno_ok_for_base_p (regno1, mode, as, PLUS, REG))
index_op = 0;
else
index_op = 1;
}
if (locI)
- scan_rtx_address (insn, locI, INDEX_REG_CLASS, action, mode);
+ scan_rtx_address (insn, locI, INDEX_REG_CLASS, action, mode, as);
if (locB)
- scan_rtx_address (insn, locB, base_reg_class (mode, PLUS, index_code),
- action, mode);
+ scan_rtx_address (insn, locB,
+ base_reg_class (mode, as, PLUS, index_code),
+ action, mode, as);
return;
}
case MEM:
scan_rtx_address (insn, &XEXP (x, 0),
- base_reg_class (GET_MODE (x), MEM, SCRATCH), action,
- GET_MODE (x));
+ base_reg_class (GET_MODE (x), MEM_ADDR_SPACE (x),
+ MEM, SCRATCH),
+ action, GET_MODE (x), MEM_ADDR_SPACE (x));
return;
case REG:
for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
{
if (fmt[i] == 'e')
- scan_rtx_address (insn, &XEXP (x, i), cl, action, mode);
+ scan_rtx_address (insn, &XEXP (x, i), cl, action, mode, as);
else if (fmt[i] == 'E')
for (j = XVECLEN (x, i) - 1; j >= 0; j--)
- scan_rtx_address (insn, &XVECEXP (x, i, j), cl, action, mode);
+ scan_rtx_address (insn, &XVECEXP (x, i, j), cl, action, mode, as);
}
}
case MEM:
scan_rtx_address (insn, &XEXP (x, 0),
- base_reg_class (GET_MODE (x), MEM, SCRATCH), action,
- GET_MODE (x));
+ base_reg_class (GET_MODE (x), MEM_ADDR_SPACE (x),
+ MEM, SCRATCH),
+ action, GET_MODE (x), MEM_ADDR_SPACE (x));
return;
case SET:
/* For each output operand of INSN, call scan_rtx to create a new
open chain. Do this only for normal or earlyclobber outputs,
- depending on EARLYCLOBBER. */
+ depending on EARLYCLOBBER. If INSN_INFO is nonnull, use it to
+ record information about the operands in the insn. */
static void
-record_out_operands (rtx insn, bool earlyclobber)
+record_out_operands (rtx insn, bool earlyclobber, insn_rr_info *insn_info)
{
int n_ops = recog_data.n_operands;
int alt = which_alternative;
|| recog_op_alt[opn][alt].earlyclobber != earlyclobber)
continue;
+ if (insn_info)
+ cur_operand = insn_info->op_info + i;
+
prev_open = open_chains;
scan_rtx (insn, loc, cl, mark_write, OP_OUT);
open_chains->cannot_rename = 1;
}
}
+ cur_operand = NULL;
}
/* Build def/use chain. */
-static struct du_head *
+static bool
build_def_use (basic_block bb)
{
rtx insn;
- df_ref *def_rec;
unsigned HOST_WIDE_INT untracked_operands;
- open_chains = closed_chains = NULL;
-
fail_current_block = false;
- current_id = 0;
- bitmap_initialize (&open_chains_set, &bitmap_default_obstack);
- CLEAR_HARD_REG_SET (live_in_chains);
- REG_SET_TO_HARD_REG_SET (live_hard_regs, df_get_live_in (bb));
- for (def_rec = df_get_artificial_defs (bb->index); *def_rec; def_rec++)
- {
- df_ref def = *def_rec;
- if (DF_REF_FLAGS (def) & DF_REF_AT_TOP)
- SET_HARD_REG_BIT (live_hard_regs, DF_REF_REGNO (def));
- }
-
for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn))
{
if (NONDEBUG_INSN_P (insn))
int predicated;
enum rtx_code set_code = SET;
enum rtx_code clobber_code = CLOBBER;
+ insn_rr_info *insn_info = NULL;
/* Process the insn, determining its effect on the def-use
chains and live hard registers. We perform the following
n_ops = recog_data.n_operands;
untracked_operands = 0;
+ if (insn_rr != NULL)
+ {
+ insn_info = VEC_index (insn_rr_info, insn_rr, INSN_UID (insn));
+ insn_info->op_info = XOBNEWVEC (&rename_obstack, operand_rr_info,
+ recog_data.n_operands);
+ memset (insn_info->op_info, 0,
+ sizeof (operand_rr_info) * recog_data.n_operands);
+ }
+
/* Simplify the code below by rewriting things to reflect
matching constraints. Also promote OP_OUT to OP_INOUT in
predicated instructions, but only for register operands
/* Step 1b: Begin new chains for earlyclobbered writes inside
operands. */
- record_out_operands (insn, true);
+ record_out_operands (insn, true, insn_info);
/* Step 2: Mark chains for which we have reads outside operands
as unrenamable.
|| untracked_operands & (1 << opn))
continue;
+ if (insn_info)
+ cur_operand = i == opn ? insn_info->op_info + i : NULL;
if (recog_op_alt[opn][alt].is_address)
- scan_rtx_address (insn, loc, cl, mark_read, VOIDmode);
+ scan_rtx_address (insn, loc, cl, mark_read,
+ VOIDmode, ADDR_SPACE_GENERIC);
else
scan_rtx (insn, loc, cl, mark_read, type);
}
+ cur_operand = NULL;
/* Step 3B: Record updates for regs in REG_INC notes, and
source regs in REG_FRAME_RELATED_EXPR notes. */
restore_operands (insn, n_ops, old_operands, old_dups);
/* Step 6b: Begin new chains for writes inside operands. */
- record_out_operands (insn, false);
+ record_out_operands (insn, false, insn_info);
/* Step 6c: Record destination regs in REG_FRAME_RELATED_EXPR
notes for update. */
break;
}
- bitmap_clear (&open_chains_set);
-
if (fail_current_block)
- return NULL;
+ return false;
- /* Since we close every chain when we find a REG_DEAD note, anything that
- is still open lives past the basic block, so it can't be renamed. */
- return closed_chains;
+ return true;
+}
+\f
+/* Initialize the register renamer. If INSN_INFO is true, ensure that
+ insn_rr is nonnull. */
+void
+regrename_init (bool insn_info)
+{
+ gcc_obstack_init (&rename_obstack);
+ insn_rr = NULL;
+ if (insn_info)
+ VEC_safe_grow_cleared (insn_rr_info, heap, insn_rr, get_max_uid ());
+}
+
+/* Free all global data used by the register renamer. */
+void
+regrename_finish (void)
+{
+ VEC_free (insn_rr_info, heap, insn_rr);
+ free_chain_data ();
+ obstack_free (&rename_obstack, NULL);
+}
+
+/* Perform register renaming on the current function. */
+
+static unsigned int
+regrename_optimize (void)
+{
+ df_set_flags (DF_LR_RUN_DCE);
+ df_note_add_problem ();
+ df_analyze ();
+ df_set_flags (DF_DEFER_INSN_RESCAN);
+
+ regrename_init (false);
+
+ regrename_analyze (NULL);
+
+ rename_chains ();
+
+ regrename_finish ();
+
+ return 0;
}
\f
static bool
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