diff options
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 70 |
1 files changed, 40 insertions, 30 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index db828e8e416..c194d663ba3 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -425,7 +425,7 @@ static rtx gen_lowpart_for_combine (enum machine_mode, rtx); static enum rtx_code simplify_comparison (enum rtx_code, rtx *, rtx *); static void update_table_tick (rtx); static void record_value_for_reg (rtx, rtx, rtx); -static void check_conversions (rtx, rtx); +static void check_promoted_subreg (rtx, rtx); static void record_dead_and_set_regs_1 (rtx, const_rtx, void *); static void record_dead_and_set_regs (rtx); static int get_last_value_validate (rtx *, rtx, int, int); @@ -441,7 +441,8 @@ static void mark_used_regs_combine (rtx); static void record_promoted_value (rtx, rtx); static int unmentioned_reg_p_1 (rtx *, void *); static bool unmentioned_reg_p (rtx, rtx); -static void record_truncated_value (rtx); +static int record_truncated_value (rtx *, void *); +static void record_truncated_values (rtx *, void *); static bool reg_truncated_to_mode (enum machine_mode, const_rtx); static rtx gen_lowpart_or_truncate (enum machine_mode, rtx); @@ -1137,7 +1138,12 @@ combine_instructions (rtx f, unsigned int nregs) { /* See if we know about function return values before this insn based upon SUBREG flags. */ - check_conversions (insn, PATTERN (insn)); + check_promoted_subreg (insn, PATTERN (insn)); + + /* See if we can find hardregs and subreg of pseudos in + narrower modes. This could help turning TRUNCATEs + into SUBREGs. */ + note_uses (&PATTERN (insn), record_truncated_values, NULL); /* Try this insn with each insn it links back to. */ @@ -1653,7 +1659,7 @@ can_combine_p (rtx insn, rtx i3, rtx pred ATTRIBUTE_UNUSED, rtx succ, /* Don't eliminate a store in the stack pointer. */ if (dest == stack_pointer_rtx /* Don't combine with an insn that sets a register to itself if it has - a REG_EQUAL note. This may be part of a REG_NO_CONFLICT sequence. */ + a REG_EQUAL note. This may be part of a LIBCALL sequence. */ || (rtx_equal_p (src, dest) && find_reg_note (insn, REG_EQUAL, NULL_RTX)) /* Can't merge an ASM_OPERANDS. */ || GET_CODE (src) == ASM_OPERANDS @@ -1696,10 +1702,6 @@ can_combine_p (rtx insn, rtx i3, rtx pred ATTRIBUTE_UNUSED, rtx succ, && use_crosses_set_p (src, DF_INSN_LUID (insn))) || (GET_CODE (src) == ASM_OPERANDS && MEM_VOLATILE_P (src)) || GET_CODE (src) == UNSPEC_VOLATILE)) - /* If there is a REG_NO_CONFLICT note for DEST in I3 or SUCC, we get - better register allocation by not doing the combine. */ - || find_reg_note (i3, REG_NO_CONFLICT, dest) - || (succ && find_reg_note (succ, REG_NO_CONFLICT, dest)) /* Don't combine across a CALL_INSN, because that would possibly change whether the life span of some REGs crosses calls or not, and it is a pain to update that information. @@ -11614,13 +11616,15 @@ reg_truncated_to_mode (enum machine_mode mode, const_rtx x) return false; } -/* X is a REG or a SUBREG. If X is some sort of a truncation record - it. For non-TRULY_NOOP_TRUNCATION targets we might be able to turn - a truncate into a subreg using this information. */ +/* Callback for for_each_rtx. If *P is a hard reg or a subreg record the mode + that the register is accessed in. For non-TRULY_NOOP_TRUNCATION targets we + might be able to turn a truncate into a subreg using this information. + Return -1 if traversing *P is complete or 0 otherwise. */ -static void -record_truncated_value (rtx x) +static int +record_truncated_value (rtx *p, void *data ATTRIBUTE_UNUSED) { + rtx x = *p; enum machine_mode truncated_mode; reg_stat_type *rsp; @@ -11630,11 +11634,11 @@ record_truncated_value (rtx x) truncated_mode = GET_MODE (x); if (GET_MODE_SIZE (original_mode) <= GET_MODE_SIZE (truncated_mode)) - return; + return -1; if (TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (truncated_mode), GET_MODE_BITSIZE (original_mode))) - return; + return -1; x = SUBREG_REG (x); } @@ -11643,7 +11647,7 @@ record_truncated_value (rtx x) else if (REG_P (x) && REGNO (x) < FIRST_PSEUDO_REGISTER) truncated_mode = GET_MODE (x); else - return; + return 0; rsp = VEC_index (reg_stat_type, reg_stat, REGNO (x)); if (rsp->truncated_to_mode == 0 @@ -11654,23 +11658,30 @@ record_truncated_value (rtx x) rsp->truncated_to_mode = truncated_mode; rsp->truncation_label = label_tick; } + + return -1; } -/* Scan X for promoted SUBREGs and truncated REGs. For each one - found, note what it implies to the registers used in it. */ +/* Callback for note_uses. Find hardregs and subregs of pseudos and + the modes they are used in. This can help truning TRUNCATEs into + SUBREGs. */ static void -check_conversions (rtx insn, rtx x) +record_truncated_values (rtx *x, void *data ATTRIBUTE_UNUSED) { - if (GET_CODE (x) == SUBREG || REG_P (x)) - { - if (GET_CODE (x) == SUBREG - && SUBREG_PROMOTED_VAR_P (x) - && REG_P (SUBREG_REG (x))) - record_promoted_value (insn, x); + for_each_rtx (x, record_truncated_value, NULL); +} - record_truncated_value (x); - } +/* Scan X for promoted SUBREGs. For each one found, + note what it implies to the registers used in it. */ + +static void +check_promoted_subreg (rtx insn, rtx x) +{ + if (GET_CODE (x) == SUBREG + && SUBREG_PROMOTED_VAR_P (x) + && REG_P (SUBREG_REG (x))) + record_promoted_value (insn, x); else { const char *format = GET_RTX_FORMAT (GET_CODE (x)); @@ -11680,13 +11691,13 @@ check_conversions (rtx insn, rtx x) switch (format[i]) { case 'e': - check_conversions (insn, XEXP (x, i)); + check_promoted_subreg (insn, XEXP (x, i)); break; case 'V': case 'E': if (XVEC (x, i) != 0) for (j = 0; j < XVECLEN (x, i); j++) - check_conversions (insn, XVECEXP (x, i, j)); + check_promoted_subreg (insn, XVECEXP (x, i, j)); break; } } @@ -12460,7 +12471,6 @@ distribute_notes (rtx notes, rtx from_insn, rtx i3, rtx i2, rtx elim_i2, break; case REG_INC: - case REG_NO_CONFLICT: /* These notes say something about how a register is used. They must be present on any use of the register in I2 or I3. */ if (reg_mentioned_p (XEXP (note, 0), PATTERN (i3))) |