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Diffstat (limited to 'gcc/regcprop.c')
| -rw-r--r-- | gcc/regcprop.c | 1194 |
1 files changed, 1194 insertions, 0 deletions
diff --git a/gcc/regcprop.c b/gcc/regcprop.c new file mode 100644 index 000000000..0f0dfb3ce --- /dev/null +++ b/gcc/regcprop.c @@ -0,0 +1,1194 @@ +/* Copy propagation on hard registers for the GNU compiler. + Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, + 2010 Free Software Foundation, Inc. + + This file is part of GCC. + + GCC is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3, or (at your option) + any later version. + + GCC is distributed in the hope that it will be useful, but WITHOUT + ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public + License for more details. + + You should have received a copy of the GNU General Public License + along with GCC; see the file COPYING3. If not see + <http://www.gnu.org/licenses/>. */ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "tm.h" +#include "rtl.h" +#include "tm_p.h" +#include "insn-config.h" +#include "regs.h" +#include "addresses.h" +#include "hard-reg-set.h" +#include "basic-block.h" +#include "reload.h" +#include "output.h" +#include "function.h" +#include "recog.h" +#include "flags.h" +#include "diagnostic-core.h" +#include "obstack.h" +#include "timevar.h" +#include "tree-pass.h" +#include "df.h" + +/* The following code does forward propagation of hard register copies. + The object is to eliminate as many dependencies as possible, so that + we have the most scheduling freedom. As a side effect, we also clean + up some silly register allocation decisions made by reload. This + code may be obsoleted by a new register allocator. */ + +/* DEBUG_INSNs aren't changed right away, as doing so might extend the + lifetime of a register and get the DEBUG_INSN subsequently reset. + So they are queued instead, and updated only when the register is + used in some subsequent real insn before it is set. */ +struct queued_debug_insn_change +{ + struct queued_debug_insn_change *next; + rtx insn; + rtx *loc; + rtx new_rtx; +}; + +/* For each register, we have a list of registers that contain the same + value. The OLDEST_REGNO field points to the head of the list, and + the NEXT_REGNO field runs through the list. The MODE field indicates + what mode the data is known to be in; this field is VOIDmode when the + register is not known to contain valid data. */ + +struct value_data_entry +{ + enum machine_mode mode; + unsigned int oldest_regno; + unsigned int next_regno; + struct queued_debug_insn_change *debug_insn_changes; +}; + +struct value_data +{ + struct value_data_entry e[FIRST_PSEUDO_REGISTER]; + unsigned int max_value_regs; + unsigned int n_debug_insn_changes; +}; + +static alloc_pool debug_insn_changes_pool; + +static void kill_value_one_regno (unsigned, struct value_data *); +static void kill_value_regno (unsigned, unsigned, struct value_data *); +static void kill_value (rtx, struct value_data *); +static void set_value_regno (unsigned, enum machine_mode, struct value_data *); +static void init_value_data (struct value_data *); +static void kill_clobbered_value (rtx, const_rtx, void *); +static void kill_set_value (rtx, const_rtx, void *); +static int kill_autoinc_value (rtx *, void *); +static void copy_value (rtx, rtx, struct value_data *); +static bool mode_change_ok (enum machine_mode, enum machine_mode, + unsigned int); +static rtx maybe_mode_change (enum machine_mode, enum machine_mode, + enum machine_mode, unsigned int, unsigned int); +static rtx find_oldest_value_reg (enum reg_class, rtx, struct value_data *); +static bool replace_oldest_value_reg (rtx *, enum reg_class, rtx, + struct value_data *); +static bool replace_oldest_value_addr (rtx *, enum reg_class, + enum machine_mode, rtx, + struct value_data *); +static bool replace_oldest_value_mem (rtx, rtx, struct value_data *); +static bool copyprop_hardreg_forward_1 (basic_block, struct value_data *); +extern void debug_value_data (struct value_data *); +#ifdef ENABLE_CHECKING +static void validate_value_data (struct value_data *); +#endif + +/* Free all queued updates for DEBUG_INSNs that change some reg to + register REGNO. */ + +static void +free_debug_insn_changes (struct value_data *vd, unsigned int regno) +{ + struct queued_debug_insn_change *cur, *next; + for (cur = vd->e[regno].debug_insn_changes; cur; cur = next) + { + next = cur->next; + --vd->n_debug_insn_changes; + pool_free (debug_insn_changes_pool, cur); + } + vd->e[regno].debug_insn_changes = NULL; +} + +/* Kill register REGNO. This involves removing it from any value + lists, and resetting the value mode to VOIDmode. This is only a + helper function; it does not handle any hard registers overlapping + with REGNO. */ + +static void +kill_value_one_regno (unsigned int regno, struct value_data *vd) +{ + unsigned int i, next; + + if (vd->e[regno].oldest_regno != regno) + { + for (i = vd->e[regno].oldest_regno; + vd->e[i].next_regno != regno; + i = vd->e[i].next_regno) + continue; + vd->e[i].next_regno = vd->e[regno].next_regno; + } + else if ((next = vd->e[regno].next_regno) != INVALID_REGNUM) + { + for (i = next; i != INVALID_REGNUM; i = vd->e[i].next_regno) + vd->e[i].oldest_regno = next; + } + + vd->e[regno].mode = VOIDmode; + vd->e[regno].oldest_regno = regno; + vd->e[regno].next_regno = INVALID_REGNUM; + if (vd->e[regno].debug_insn_changes) + free_debug_insn_changes (vd, regno); + +#ifdef ENABLE_CHECKING + validate_value_data (vd); +#endif +} + +/* Kill the value in register REGNO for NREGS, and any other registers + whose values overlap. */ + +static void +kill_value_regno (unsigned int regno, unsigned int nregs, + struct value_data *vd) +{ + unsigned int j; + + /* Kill the value we're told to kill. */ + for (j = 0; j < nregs; ++j) + kill_value_one_regno (regno + j, vd); + + /* Kill everything that overlapped what we're told to kill. */ + if (regno < vd->max_value_regs) + j = 0; + else + j = regno - vd->max_value_regs; + for (; j < regno; ++j) + { + unsigned int i, n; + if (vd->e[j].mode == VOIDmode) + continue; + n = hard_regno_nregs[j][vd->e[j].mode]; + if (j + n > regno) + for (i = 0; i < n; ++i) + kill_value_one_regno (j + i, vd); + } +} + +/* Kill X. This is a convenience function wrapping kill_value_regno + so that we mind the mode the register is in. */ + +static void +kill_value (rtx x, struct value_data *vd) +{ + rtx orig_rtx = x; + + if (GET_CODE (x) == SUBREG) + { + x = simplify_subreg (GET_MODE (x), SUBREG_REG (x), + GET_MODE (SUBREG_REG (x)), SUBREG_BYTE (x)); + if (x == NULL_RTX) + x = SUBREG_REG (orig_rtx); + } + if (REG_P (x)) + { + unsigned int regno = REGNO (x); + unsigned int n = hard_regno_nregs[regno][GET_MODE (x)]; + + kill_value_regno (regno, n, vd); + } +} + +/* Remember that REGNO is valid in MODE. */ + +static void +set_value_regno (unsigned int regno, enum machine_mode mode, + struct value_data *vd) +{ + unsigned int nregs; + + vd->e[regno].mode = mode; + + nregs = hard_regno_nregs[regno][mode]; + if (nregs > vd->max_value_regs) + vd->max_value_regs = nregs; +} + +/* Initialize VD such that there are no known relationships between regs. */ + +static void +init_value_data (struct value_data *vd) +{ + int i; + for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i) + { + vd->e[i].mode = VOIDmode; + vd->e[i].oldest_regno = i; + vd->e[i].next_regno = INVALID_REGNUM; + vd->e[i].debug_insn_changes = NULL; + } + vd->max_value_regs = 0; + vd->n_debug_insn_changes = 0; +} + +/* Called through note_stores. If X is clobbered, kill its value. */ + +static void +kill_clobbered_value (rtx x, const_rtx set, void *data) +{ + struct value_data *const vd = (struct value_data *) data; + if (GET_CODE (set) == CLOBBER) + kill_value (x, vd); +} + +/* Called through note_stores. If X is set, not clobbered, kill its + current value and install it as the root of its own value list. */ + +static void +kill_set_value (rtx x, const_rtx set, void *data) +{ + struct value_data *const vd = (struct value_data *) data; + if (GET_CODE (set) != CLOBBER) + { + kill_value (x, vd); + if (REG_P (x)) + set_value_regno (REGNO (x), GET_MODE (x), vd); + } +} + +/* Called through for_each_rtx. Kill any register used as the base of an + auto-increment expression, and install that register as the root of its + own value list. */ + +static int +kill_autoinc_value (rtx *px, void *data) +{ + rtx x = *px; + struct value_data *const vd = (struct value_data *) data; + + if (GET_RTX_CLASS (GET_CODE (x)) == RTX_AUTOINC) + { + x = XEXP (x, 0); + kill_value (x, vd); + set_value_regno (REGNO (x), GET_MODE (x), vd); + return -1; + } + + return 0; +} + +/* Assert that SRC has been copied to DEST. Adjust the data structures + to reflect that SRC contains an older copy of the shared value. */ + +static void +copy_value (rtx dest, rtx src, struct value_data *vd) +{ + unsigned int dr = REGNO (dest); + unsigned int sr = REGNO (src); + unsigned int dn, sn; + unsigned int i; + + /* ??? At present, it's possible to see noop sets. It'd be nice if + this were cleaned up beforehand... */ + if (sr == dr) + return; + + /* Do not propagate copies to the stack pointer, as that can leave + memory accesses with no scheduling dependency on the stack update. */ + if (dr == STACK_POINTER_REGNUM) + return; + + /* Likewise with the frame pointer, if we're using one. */ + if (frame_pointer_needed && dr == HARD_FRAME_POINTER_REGNUM) + return; + + /* Do not propagate copies to fixed or global registers, patterns + can be relying to see particular fixed register or users can + expect the chosen global register in asm. */ + if (fixed_regs[dr] || global_regs[dr]) + return; + + /* If SRC and DEST overlap, don't record anything. */ + dn = hard_regno_nregs[dr][GET_MODE (dest)]; + sn = hard_regno_nregs[sr][GET_MODE (dest)]; + if ((dr > sr && dr < sr + sn) + || (sr > dr && sr < dr + dn)) + return; + + /* If SRC had no assigned mode (i.e. we didn't know it was live) + assign it now and assume the value came from an input argument + or somesuch. */ + if (vd->e[sr].mode == VOIDmode) + set_value_regno (sr, vd->e[dr].mode, vd); + + /* If we are narrowing the input to a smaller number of hard regs, + and it is in big endian, we are really extracting a high part. + Since we generally associate a low part of a value with the value itself, + we must not do the same for the high part. + Note we can still get low parts for the same mode combination through + a two-step copy involving differently sized hard regs. + Assume hard regs fr* are 32 bits bits each, while r* are 64 bits each: + (set (reg:DI r0) (reg:DI fr0)) + (set (reg:SI fr2) (reg:SI r0)) + loads the low part of (reg:DI fr0) - i.e. fr1 - into fr2, while: + (set (reg:SI fr2) (reg:SI fr0)) + loads the high part of (reg:DI fr0) into fr2. + + We can't properly represent the latter case in our tables, so don't + record anything then. */ + else if (sn < (unsigned int) hard_regno_nregs[sr][vd->e[sr].mode] + && (GET_MODE_SIZE (vd->e[sr].mode) > UNITS_PER_WORD + ? WORDS_BIG_ENDIAN : BYTES_BIG_ENDIAN)) + return; + + /* If SRC had been assigned a mode narrower than the copy, we can't + link DEST into the chain, because not all of the pieces of the + copy came from oldest_regno. */ + else if (sn > (unsigned int) hard_regno_nregs[sr][vd->e[sr].mode]) + return; + + /* Link DR at the end of the value chain used by SR. */ + + vd->e[dr].oldest_regno = vd->e[sr].oldest_regno; + + for (i = sr; vd->e[i].next_regno != INVALID_REGNUM; i = vd->e[i].next_regno) + continue; + vd->e[i].next_regno = dr; + +#ifdef ENABLE_CHECKING + validate_value_data (vd); +#endif +} + +/* Return true if a mode change from ORIG to NEW is allowed for REGNO. */ + +static bool +mode_change_ok (enum machine_mode orig_mode, enum machine_mode new_mode, + unsigned int regno ATTRIBUTE_UNUSED) +{ + if (GET_MODE_SIZE (orig_mode) < GET_MODE_SIZE (new_mode)) + return false; + +#ifdef CANNOT_CHANGE_MODE_CLASS + return !REG_CANNOT_CHANGE_MODE_P (regno, orig_mode, new_mode); +#endif + + return true; +} + +/* Register REGNO was originally set in ORIG_MODE. It - or a copy of it - + was copied in COPY_MODE to COPY_REGNO, and then COPY_REGNO was accessed + in NEW_MODE. + Return a NEW_MODE rtx for REGNO if that's OK, otherwise return NULL_RTX. */ + +static rtx +maybe_mode_change (enum machine_mode orig_mode, enum machine_mode copy_mode, + enum machine_mode new_mode, unsigned int regno, + unsigned int copy_regno ATTRIBUTE_UNUSED) +{ + if (GET_MODE_SIZE (copy_mode) < GET_MODE_SIZE (orig_mode) + && GET_MODE_SIZE (copy_mode) < GET_MODE_SIZE (new_mode)) + return NULL_RTX; + + if (orig_mode == new_mode) + return gen_rtx_raw_REG (new_mode, regno); + else if (mode_change_ok (orig_mode, new_mode, regno)) + { + int copy_nregs = hard_regno_nregs[copy_regno][copy_mode]; + int use_nregs = hard_regno_nregs[copy_regno][new_mode]; + int copy_offset + = GET_MODE_SIZE (copy_mode) / copy_nregs * (copy_nregs - use_nregs); + int offset + = GET_MODE_SIZE (orig_mode) - GET_MODE_SIZE (new_mode) - copy_offset; + int byteoffset = offset % UNITS_PER_WORD; + int wordoffset = offset - byteoffset; + + offset = ((WORDS_BIG_ENDIAN ? wordoffset : 0) + + (BYTES_BIG_ENDIAN ? byteoffset : 0)); + return gen_rtx_raw_REG (new_mode, + regno + subreg_regno_offset (regno, orig_mode, + offset, + new_mode)); + } + return NULL_RTX; +} + +/* Find the oldest copy of the value contained in REGNO that is in + register class CL and has mode MODE. If found, return an rtx + of that oldest register, otherwise return NULL. */ + +static rtx +find_oldest_value_reg (enum reg_class cl, rtx reg, struct value_data *vd) +{ + unsigned int regno = REGNO (reg); + enum machine_mode mode = GET_MODE (reg); + unsigned int i; + + /* If we are accessing REG in some mode other that what we set it in, + make sure that the replacement is valid. In particular, consider + (set (reg:DI r11) (...)) + (set (reg:SI r9) (reg:SI r11)) + (set (reg:SI r10) (...)) + (set (...) (reg:DI r9)) + Replacing r9 with r11 is invalid. */ + if (mode != vd->e[regno].mode) + { + if (hard_regno_nregs[regno][mode] + > hard_regno_nregs[regno][vd->e[regno].mode]) + return NULL_RTX; + } + + for (i = vd->e[regno].oldest_regno; i != regno; i = vd->e[i].next_regno) + { + enum machine_mode oldmode = vd->e[i].mode; + rtx new_rtx; + + if (!in_hard_reg_set_p (reg_class_contents[cl], mode, i)) + continue; + + new_rtx = maybe_mode_change (oldmode, vd->e[regno].mode, mode, i, regno); + if (new_rtx) + { + ORIGINAL_REGNO (new_rtx) = ORIGINAL_REGNO (reg); + REG_ATTRS (new_rtx) = REG_ATTRS (reg); + REG_POINTER (new_rtx) = REG_POINTER (reg); + return new_rtx; + } + } + + return NULL_RTX; +} + +/* If possible, replace the register at *LOC with the oldest register + in register class CL. Return true if successfully replaced. */ + +static bool +replace_oldest_value_reg (rtx *loc, enum reg_class cl, rtx insn, + struct value_data *vd) +{ + rtx new_rtx = find_oldest_value_reg (cl, *loc, vd); + if (new_rtx) + { + if (DEBUG_INSN_P (insn)) + { + struct queued_debug_insn_change *change; + + if (dump_file) + fprintf (dump_file, "debug_insn %u: queued replacing reg %u with %u\n", + INSN_UID (insn), REGNO (*loc), REGNO (new_rtx)); + + change = (struct queued_debug_insn_change *) + pool_alloc (debug_insn_changes_pool); + change->next = vd->e[REGNO (new_rtx)].debug_insn_changes; + change->insn = insn; + change->loc = loc; + change->new_rtx = new_rtx; + vd->e[REGNO (new_rtx)].debug_insn_changes = change; + ++vd->n_debug_insn_changes; + return true; + } + if (dump_file) + fprintf (dump_file, "insn %u: replaced reg %u with %u\n", + INSN_UID (insn), REGNO (*loc), REGNO (new_rtx)); + + validate_change (insn, loc, new_rtx, 1); + return true; + } + return false; +} + +/* Similar to replace_oldest_value_reg, but *LOC contains an address. + Adapted from find_reloads_address_1. CL is INDEX_REG_CLASS or + BASE_REG_CLASS depending on how the register is being considered. */ + +static bool +replace_oldest_value_addr (rtx *loc, enum reg_class cl, + enum machine_mode mode, rtx insn, + struct value_data *vd) +{ + rtx x = *loc; + RTX_CODE code = GET_CODE (x); + const char *fmt; + int i, j; + bool changed = false; + + switch (code) + { + case PLUS: + if (DEBUG_INSN_P (insn)) + break; + + { + rtx orig_op0 = XEXP (x, 0); + rtx orig_op1 = XEXP (x, 1); + RTX_CODE code0 = GET_CODE (orig_op0); + RTX_CODE code1 = GET_CODE (orig_op1); + rtx op0 = orig_op0; + rtx op1 = orig_op1; + rtx *locI = NULL; + rtx *locB = NULL; + enum rtx_code index_code = SCRATCH; + + if (GET_CODE (op0) == SUBREG) + { + op0 = SUBREG_REG (op0); + code0 = GET_CODE (op0); + } + + if (GET_CODE (op1) == SUBREG) + { + op1 = SUBREG_REG (op1); + code1 = GET_CODE (op1); + } + + if (code0 == MULT || code0 == SIGN_EXTEND || code0 == TRUNCATE + || code0 == ZERO_EXTEND || code1 == MEM) + { + locI = &XEXP (x, 0); + locB = &XEXP (x, 1); + index_code = GET_CODE (*locI); + } + else if (code1 == MULT || code1 == SIGN_EXTEND || code1 == TRUNCATE + || code1 == ZERO_EXTEND || code0 == MEM) + { + locI = &XEXP (x, 1); + locB = &XEXP (x, 0); + index_code = GET_CODE (*locI); + } + else if (code0 == CONST_INT || code0 == CONST + || code0 == SYMBOL_REF || code0 == LABEL_REF) + { + locB = &XEXP (x, 1); + index_code = GET_CODE (XEXP (x, 0)); + } + else if (code1 == CONST_INT || code1 == CONST + || code1 == SYMBOL_REF || code1 == LABEL_REF) + { + locB = &XEXP (x, 0); + index_code = GET_CODE (XEXP (x, 1)); + } + else if (code0 == REG && code1 == REG) + { + int index_op; + unsigned regno0 = REGNO (op0), regno1 = REGNO (op1); + + if (REGNO_OK_FOR_INDEX_P (regno1) + && regno_ok_for_base_p (regno0, mode, PLUS, REG)) + index_op = 1; + else if (REGNO_OK_FOR_INDEX_P (regno0) + && regno_ok_for_base_p (regno1, mode, PLUS, REG)) + index_op = 0; + else if (regno_ok_for_base_p (regno0, mode, PLUS, REG) + || REGNO_OK_FOR_INDEX_P (regno1)) + index_op = 1; + else if (regno_ok_for_base_p (regno1, mode, PLUS, REG)) + index_op = 0; + else + index_op = 1; + + locI = &XEXP (x, index_op); + locB = &XEXP (x, !index_op); + index_code = GET_CODE (*locI); + } + else if (code0 == REG) + { + locI = &XEXP (x, 0); + locB = &XEXP (x, 1); + index_code = GET_CODE (*locI); + } + else if (code1 == REG) + { + locI = &XEXP (x, 1); + locB = &XEXP (x, 0); + index_code = GET_CODE (*locI); + } + + if (locI) + changed |= replace_oldest_value_addr (locI, INDEX_REG_CLASS, mode, + insn, vd); + if (locB) + changed |= replace_oldest_value_addr (locB, + base_reg_class (mode, PLUS, + index_code), + mode, insn, vd); + return changed; + } + + case POST_INC: + case POST_DEC: + case POST_MODIFY: + case PRE_INC: + case PRE_DEC: + case PRE_MODIFY: + return false; + + case MEM: + return replace_oldest_value_mem (x, insn, vd); + + case REG: + return replace_oldest_value_reg (loc, cl, insn, vd); + + default: + break; + } + + fmt = GET_RTX_FORMAT (code); + for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) + { + if (fmt[i] == 'e') + changed |= replace_oldest_value_addr (&XEXP (x, i), cl, mode, + insn, vd); + else if (fmt[i] == 'E') + for (j = XVECLEN (x, i) - 1; j >= 0; j--) + changed |= replace_oldest_value_addr (&XVECEXP (x, i, j), cl, + mode, insn, vd); + } + + return changed; +} + +/* Similar to replace_oldest_value_reg, but X contains a memory. */ + +static bool +replace_oldest_value_mem (rtx x, rtx insn, struct value_data *vd) +{ + enum reg_class cl; + + if (DEBUG_INSN_P (insn)) + cl = ALL_REGS; + else + cl = base_reg_class (GET_MODE (x), MEM, SCRATCH); + + return replace_oldest_value_addr (&XEXP (x, 0), cl, + GET_MODE (x), insn, vd); +} + +/* Apply all queued updates for DEBUG_INSNs that change some reg to + register REGNO. */ + +static void +apply_debug_insn_changes (struct value_data *vd, unsigned int regno) +{ + struct queued_debug_insn_change *change; + rtx last_insn = vd->e[regno].debug_insn_changes->insn; + + for (change = vd->e[regno].debug_insn_changes; + change; + change = change->next) + { + if (last_insn != change->insn) + { + apply_change_group (); + last_insn = change->insn; + } + validate_change (change->insn, change->loc, change->new_rtx, 1); + } + apply_change_group (); +} + +/* Called via for_each_rtx, for all used registers in a real + insn apply DEBUG_INSN changes that change registers to the + used register. */ + +static int +cprop_find_used_regs_1 (rtx *loc, void *data) +{ + if (REG_P (*loc)) + { + struct value_data *vd = (struct value_data *) data; + if (vd->e[REGNO (*loc)].debug_insn_changes) + { + apply_debug_insn_changes (vd, REGNO (*loc)); + free_debug_insn_changes (vd, REGNO (*loc)); + } + } + return 0; +} + +/* Called via note_uses, for all used registers in a real insn + apply DEBUG_INSN changes that change registers to the used + registers. */ + +static void +cprop_find_used_regs (rtx *loc, void *vd) +{ + for_each_rtx (loc, cprop_find_used_regs_1, vd); +} + +/* Perform the forward copy propagation on basic block BB. */ + +static bool +copyprop_hardreg_forward_1 (basic_block bb, struct value_data *vd) +{ + bool anything_changed = false; + rtx insn; + + for (insn = BB_HEAD (bb); ; insn = NEXT_INSN (insn)) + { + int n_ops, i, alt, predicated; + bool is_asm, any_replacements; + rtx set; + bool replaced[MAX_RECOG_OPERANDS]; + bool changed = false; + + if (!NONDEBUG_INSN_P (insn)) + { + if (DEBUG_INSN_P (insn)) + { + rtx loc = INSN_VAR_LOCATION_LOC (insn); + if (!VAR_LOC_UNKNOWN_P (loc)) + replace_oldest_value_addr (&INSN_VAR_LOCATION_LOC (insn), + ALL_REGS, GET_MODE (loc), + insn, vd); + } + + if (insn == BB_END (bb)) + break; + else + continue; + } + + set = single_set (insn); + extract_insn (insn); + if (! constrain_operands (1)) + fatal_insn_not_found (insn); + preprocess_constraints (); + alt = which_alternative; + n_ops = recog_data.n_operands; + is_asm = asm_noperands (PATTERN (insn)) >= 0; + + /* Simplify the code below by rewriting things to reflect + matching constraints. Also promote OP_OUT to OP_INOUT + in predicated instructions. */ + + predicated = GET_CODE (PATTERN (insn)) == COND_EXEC; + for (i = 0; i < n_ops; ++i) + { + int matches = recog_op_alt[i][alt].matches; + if (matches >= 0) + recog_op_alt[i][alt].cl = recog_op_alt[matches][alt].cl; + if (matches >= 0 || recog_op_alt[i][alt].matched >= 0 + || (predicated && recog_data.operand_type[i] == OP_OUT)) + recog_data.operand_type[i] = OP_INOUT; + } + + /* Apply changes to earlier DEBUG_INSNs if possible. */ + if (vd->n_debug_insn_changes) + note_uses (&PATTERN (insn), cprop_find_used_regs, vd); + + /* For each earlyclobber operand, zap the value data. */ + for (i = 0; i < n_ops; i++) + if (recog_op_alt[i][alt].earlyclobber) + kill_value (recog_data.operand[i], vd); + + /* Within asms, a clobber cannot overlap inputs or outputs. + I wouldn't think this were true for regular insns, but + scan_rtx treats them like that... */ + note_stores (PATTERN (insn), kill_clobbered_value, vd); + + /* Kill all auto-incremented values. */ + /* ??? REG_INC is useless, since stack pushes aren't done that way. */ + for_each_rtx (&PATTERN (insn), kill_autoinc_value, vd); + + /* Kill all early-clobbered operands. */ + for (i = 0; i < n_ops; i++) + if (recog_op_alt[i][alt].earlyclobber) + kill_value (recog_data.operand[i], vd); + + /* Special-case plain move instructions, since we may well + be able to do the move from a different register class. */ + if (set && REG_P (SET_SRC (set))) + { + rtx src = SET_SRC (set); + unsigned int regno = REGNO (src); + enum machine_mode mode = GET_MODE (src); + unsigned int i; + rtx new_rtx; + + /* If we are accessing SRC in some mode other that what we + set it in, make sure that the replacement is valid. */ + if (mode != vd->e[regno].mode) + { + if (hard_regno_nregs[regno][mode] + > hard_regno_nregs[regno][vd->e[regno].mode]) + goto no_move_special_case; + } + + /* If the destination is also a register, try to find a source + register in the same class. */ + if (REG_P (SET_DEST (set))) + { + new_rtx = find_oldest_value_reg (REGNO_REG_CLASS (regno), src, vd); + if (new_rtx && validate_change (insn, &SET_SRC (set), new_rtx, 0)) + { + if (dump_file) + fprintf (dump_file, + "insn %u: replaced reg %u with %u\n", + INSN_UID (insn), regno, REGNO (new_rtx)); + changed = true; + goto did_replacement; + } + } + + /* Otherwise, try all valid registers and see if its valid. */ + for (i = vd->e[regno].oldest_regno; i != regno; + i = vd->e[i].next_regno) + { + new_rtx = maybe_mode_change (vd->e[i].mode, vd->e[regno].mode, + mode, i, regno); + if (new_rtx != NULL_RTX) + { + if (validate_change (insn, &SET_SRC (set), new_rtx, 0)) + { + ORIGINAL_REGNO (new_rtx) = ORIGINAL_REGNO (src); + REG_ATTRS (new_rtx) = REG_ATTRS (src); + REG_POINTER (new_rtx) = REG_POINTER (src); + if (dump_file) + fprintf (dump_file, + "insn %u: replaced reg %u with %u\n", + INSN_UID (insn), regno, REGNO (new_rtx)); + changed = true; + goto did_replacement; + } + } + } + } + no_move_special_case: + + any_replacements = false; + + /* For each input operand, replace a hard register with the + eldest live copy that's in an appropriate register class. */ + for (i = 0; i < n_ops; i++) + { + replaced[i] = false; + + /* Don't scan match_operand here, since we've no reg class + information to pass down. Any operands that we could + substitute in will be represented elsewhere. */ + if (recog_data.constraints[i][0] == '\0') + continue; + + /* Don't replace in asms intentionally referencing hard regs. */ + if (is_asm && REG_P (recog_data.operand[i]) + && (REGNO (recog_data.operand[i]) + == ORIGINAL_REGNO (recog_data.operand[i]))) + continue; + + if (recog_data.operand_type[i] == OP_IN) + { + if (recog_op_alt[i][alt].is_address) + replaced[i] + = replace_oldest_value_addr (recog_data.operand_loc[i], + recog_op_alt[i][alt].cl, + VOIDmode, insn, vd); + else if (REG_P (recog_data.operand[i])) + replaced[i] + = replace_oldest_value_reg (recog_data.operand_loc[i], + recog_op_alt[i][alt].cl, + insn, vd); + else if (MEM_P (recog_data.operand[i])) + replaced[i] = replace_oldest_value_mem (recog_data.operand[i], + insn, vd); + } + else if (MEM_P (recog_data.operand[i])) + replaced[i] = replace_oldest_value_mem (recog_data.operand[i], + insn, vd); + + /* If we performed any replacement, update match_dups. */ + if (replaced[i]) + { + int j; + rtx new_rtx; + + new_rtx = *recog_data.operand_loc[i]; + recog_data.operand[i] = new_rtx; + for (j = 0; j < recog_data.n_dups; j++) + if (recog_data.dup_num[j] == i) + validate_unshare_change (insn, recog_data.dup_loc[j], new_rtx, 1); + + any_replacements = true; + } + } + + if (any_replacements) + { + if (! apply_change_group ()) + { + for (i = 0; i < n_ops; i++) + if (replaced[i]) + { + rtx old = *recog_data.operand_loc[i]; + recog_data.operand[i] = old; + } + + if (dump_file) + fprintf (dump_file, + "insn %u: reg replacements not verified\n", + INSN_UID (insn)); + } + else + changed = true; + } + + did_replacement: + if (changed) + { + anything_changed = true; + + /* If something changed, perhaps further changes to earlier + DEBUG_INSNs can be applied. */ + if (vd->n_debug_insn_changes) + note_uses (&PATTERN (insn), cprop_find_used_regs, vd); + } + + /* Clobber call-clobbered registers. */ + if (CALL_P (insn)) + for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) + if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i)) + kill_value_regno (i, 1, vd); + + /* Notice stores. */ + note_stores (PATTERN (insn), kill_set_value, vd); + + /* Notice copies. */ + if (set && REG_P (SET_DEST (set)) && REG_P (SET_SRC (set))) + copy_value (SET_DEST (set), SET_SRC (set), vd); + + if (insn == BB_END (bb)) + break; + } + + return anything_changed; +} + +/* Main entry point for the forward copy propagation optimization. */ + +static unsigned int +copyprop_hardreg_forward (void) +{ + struct value_data *all_vd; + basic_block bb; + sbitmap visited; + bool analyze_called = false; + + all_vd = XNEWVEC (struct value_data, last_basic_block); + + visited = sbitmap_alloc (last_basic_block); + sbitmap_zero (visited); + + if (MAY_HAVE_DEBUG_STMTS) + debug_insn_changes_pool + = create_alloc_pool ("debug insn changes pool", + sizeof (struct queued_debug_insn_change), 256); + + FOR_EACH_BB (bb) + { + SET_BIT (visited, bb->index); + + /* If a block has a single predecessor, that we've already + processed, begin with the value data that was live at + the end of the predecessor block. */ + /* ??? Ought to use more intelligent queuing of blocks. */ + if (single_pred_p (bb) + && TEST_BIT (visited, single_pred (bb)->index) + && ! (single_pred_edge (bb)->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))) + { + all_vd[bb->index] = all_vd[single_pred (bb)->index]; + if (all_vd[bb->index].n_debug_insn_changes) + { + unsigned int regno; + + for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) + { + if (all_vd[bb->index].e[regno].debug_insn_changes) + { + all_vd[bb->index].e[regno].debug_insn_changes = NULL; + if (--all_vd[bb->index].n_debug_insn_changes == 0) + break; + } + } + } + } + else + init_value_data (all_vd + bb->index); + + copyprop_hardreg_forward_1 (bb, all_vd + bb->index); + } + + if (MAY_HAVE_DEBUG_STMTS) + { + FOR_EACH_BB (bb) + if (TEST_BIT (visited, bb->index) + && all_vd[bb->index].n_debug_insn_changes) + { + unsigned int regno; + bitmap live; + + if (!analyze_called) + { + df_analyze (); + analyze_called = true; + } + live = df_get_live_out (bb); + for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) + if (all_vd[bb->index].e[regno].debug_insn_changes) + { + if (REGNO_REG_SET_P (live, regno)) + apply_debug_insn_changes (all_vd + bb->index, regno); + if (all_vd[bb->index].n_debug_insn_changes == 0) + break; + } + } + + free_alloc_pool (debug_insn_changes_pool); + } + + sbitmap_free (visited); + free (all_vd); + return 0; +} + +/* Dump the value chain data to stderr. */ + +DEBUG_FUNCTION void +debug_value_data (struct value_data *vd) +{ + HARD_REG_SET set; + unsigned int i, j; + + CLEAR_HARD_REG_SET (set); + + for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i) + if (vd->e[i].oldest_regno == i) + { + if (vd->e[i].mode == VOIDmode) + { + if (vd->e[i].next_regno != INVALID_REGNUM) + fprintf (stderr, "[%u] Bad next_regno for empty chain (%u)\n", + i, vd->e[i].next_regno); + continue; + } + + SET_HARD_REG_BIT (set, i); + fprintf (stderr, "[%u %s] ", i, GET_MODE_NAME (vd->e[i].mode)); + + for (j = vd->e[i].next_regno; + j != INVALID_REGNUM; + j = vd->e[j].next_regno) + { + if (TEST_HARD_REG_BIT (set, j)) + { + fprintf (stderr, "[%u] Loop in regno chain\n", j); + return; + } + + if (vd->e[j].oldest_regno != i) + { + fprintf (stderr, "[%u] Bad oldest_regno (%u)\n", + j, vd->e[j].oldest_regno); + return; + } + SET_HARD_REG_BIT (set, j); + fprintf (stderr, "[%u %s] ", j, GET_MODE_NAME (vd->e[j].mode)); + } + fputc ('\n', stderr); + } + + for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i) + if (! TEST_HARD_REG_BIT (set, i) + && (vd->e[i].mode != VOIDmode + || vd->e[i].oldest_regno != i + || vd->e[i].next_regno != INVALID_REGNUM)) + fprintf (stderr, "[%u] Non-empty reg in chain (%s %u %i)\n", + i, GET_MODE_NAME (vd->e[i].mode), vd->e[i].oldest_regno, + vd->e[i].next_regno); +} + +#ifdef ENABLE_CHECKING +static void +validate_value_data (struct value_data *vd) +{ + HARD_REG_SET set; + unsigned int i, j; + + CLEAR_HARD_REG_SET (set); + + for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i) + if (vd->e[i].oldest_regno == i) + { + if (vd->e[i].mode == VOIDmode) + { + if (vd->e[i].next_regno != INVALID_REGNUM) + internal_error ("validate_value_data: [%u] Bad next_regno for empty chain (%u)", + i, vd->e[i].next_regno); + continue; + } + + SET_HARD_REG_BIT (set, i); + + for (j = vd->e[i].next_regno; + j != INVALID_REGNUM; + j = vd->e[j].next_regno) + { + if (TEST_HARD_REG_BIT (set, j)) + internal_error ("validate_value_data: Loop in regno chain (%u)", + j); + if (vd->e[j].oldest_regno != i) + internal_error ("validate_value_data: [%u] Bad oldest_regno (%u)", + j, vd->e[j].oldest_regno); + + SET_HARD_REG_BIT (set, j); + } + } + + for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i) + if (! TEST_HARD_REG_BIT (set, i) + && (vd->e[i].mode != VOIDmode + || vd->e[i].oldest_regno != i + || vd->e[i].next_regno != INVALID_REGNUM)) + internal_error ("validate_value_data: [%u] Non-empty reg in chain (%s %u %i)", + i, GET_MODE_NAME (vd->e[i].mode), vd->e[i].oldest_regno, + vd->e[i].next_regno); +} +#endif + +static bool +gate_handle_cprop (void) +{ + return (optimize > 0 && (flag_cprop_registers)); +} + + +struct rtl_opt_pass pass_cprop_hardreg = +{ + { + RTL_PASS, + "cprop_hardreg", /* name */ + gate_handle_cprop, /* gate */ + copyprop_hardreg_forward, /* execute */ + NULL, /* sub */ + NULL, /* next */ + 0, /* static_pass_number */ + TV_CPROP_REGISTERS, /* tv_id */ + 0, /* properties_required */ + 0, /* properties_provided */ + 0, /* properties_destroyed */ + 0, /* todo_flags_start */ + TODO_dump_func | TODO_df_finish + | TODO_verify_rtl_sharing /* todo_flags_finish */ + } +}; |