From 178667d2fd4882d33d34fc66f9514a6fde418fe9 Mon Sep 17 00:00:00 2001 From: Segher Boessenkool Date: Mon, 4 Dec 2017 16:38:20 +0100 Subject: [PATCH] combine: Remove use_crosses_set_p This removes use_crosses_set_p, and uses modified_between_p instead everywhere it was used. This improves optimisation. * combine.c: Adjust comment. (use_crosses_set_p): Delete. (can_combine_p): Use modified_between_p instead of use_crosses_set_p. (try_combine): Ditto. From-SVN: r255384 --- gcc/ChangeLog | 7 ++++++ gcc/combine.c | 69 ++++++--------------------------------------------- 2 files changed, 14 insertions(+), 62 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index c73452a5f09..4b072b4ceec 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2017-12-04 Segher Boessenkool + + * combine.c: Adjust comment. + (use_crosses_set_p): Delete. + (can_combine_p): Use modified_between_p instead of use_crosses_set_p. + (try_combine): Ditto. + 2017-12-04 Richard Biener PR tree-optimization/83255 diff --git a/gcc/combine.c b/gcc/combine.c index 863abd7a282..34c89a129e1 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -39,7 +39,7 @@ along with GCC; see the file COPYING3. If not see insn as having a logical link to the preceding insn. The same is true for an insn explicitly using CC0. - We check (with use_crosses_set_p) to avoid combining in such a way + We check (with modified_between_p) to avoid combining in such a way as to move a computation to a place where its value would be different. Combination is done by mathematically substituting the previous @@ -482,7 +482,6 @@ static void record_dead_and_set_regs_1 (rtx, const_rtx, void *); static void record_dead_and_set_regs (rtx_insn *); static int get_last_value_validate (rtx *, rtx_insn *, int, int); static rtx get_last_value (const_rtx); -static int use_crosses_set_p (const_rtx, int); static void reg_dead_at_p_1 (rtx, const_rtx, void *); static int reg_dead_at_p (rtx, rtx_insn *); static void move_deaths (rtx, rtx, int, rtx_insn *, rtx *); @@ -2011,7 +2010,7 @@ can_combine_p (rtx_insn *insn, rtx_insn *i3, rtx_insn *pred ATTRIBUTE_UNUSED, || (! all_adjacent && (((!MEM_P (src) || ! find_reg_note (insn, REG_EQUIV, src)) - && use_crosses_set_p (src, DF_INSN_LUID (insn))) + && modified_between_p (src, insn, i3)) || (GET_CODE (src) == ASM_OPERANDS && MEM_VOLATILE_P (src)) || GET_CODE (src) == UNSPEC_VOLATILE)) /* Don't combine across a CALL_INSN, because that would possibly @@ -3699,7 +3698,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, } else if (m_split_insn && NEXT_INSN (NEXT_INSN (m_split_insn)) == NULL_RTX && (next_nonnote_nondebug_insn (i2) == i3 - || ! use_crosses_set_p (PATTERN (m_split_insn), DF_INSN_LUID (i2)))) + || !modified_between_p (PATTERN (m_split_insn), i2, i3))) { rtx i2set, i3set; rtx newi3pat = PATTERN (NEXT_INSN (m_split_insn)); @@ -3763,7 +3762,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, || can_change_dest_mode (i2dest, added_sets_2, GET_MODE (*split))) && (next_nonnote_nondebug_insn (i2) == i3 - || ! use_crosses_set_p (*split, DF_INSN_LUID (i2))) + || !modified_between_p (*split, i2, i3)) /* We can't overwrite I2DEST if its value is still used by NEWPAT. */ && ! reg_referenced_p (i2dest, newpat)) @@ -3954,8 +3953,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, && GET_CODE (XVECEXP (newpat, 0, 1)) == SET && rtx_equal_p (SET_SRC (XVECEXP (newpat, 0, 1)), XEXP (SET_SRC (XVECEXP (newpat, 0, 0)), 0)) - && ! use_crosses_set_p (SET_SRC (XVECEXP (newpat, 0, 1)), - DF_INSN_LUID (i2)) + && !modified_between_p (SET_SRC (XVECEXP (newpat, 0, 1)), i2, i3) && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != ZERO_EXTRACT && GET_CODE (SET_DEST (XVECEXP (newpat, 0, 1))) != STRICT_LOW_PART && ! (temp_expr = SET_DEST (XVECEXP (newpat, 0, 1)), @@ -4029,7 +4027,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, be first. The PARALLEL might also have been pre-existing in i3, so we need to make sure that we won't wrongly hoist a SET to i2 that would conflict with a death note present in there. */ - if (!use_crosses_set_p (SET_SRC (set1), DF_INSN_LUID (i2)) + if (!modified_between_p (SET_SRC (set1), i2, i3) && !(REG_P (SET_DEST (set1)) && find_reg_note (i2, REG_DEAD, SET_DEST (set1))) && !(GET_CODE (SET_DEST (set1)) == SUBREG @@ -4044,7 +4042,7 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0, newi2pat = set1; newpat = set0; } - else if (!use_crosses_set_p (SET_SRC (set0), DF_INSN_LUID (i2)) + else if (!modified_between_p (SET_SRC (set0), i2, i3) && !(REG_P (SET_DEST (set0)) && find_reg_note (i2, REG_DEAD, SET_DEST (set0))) && !(GET_CODE (SET_DEST (set0)) == SUBREG @@ -13661,59 +13659,6 @@ get_last_value (const_rtx x) return 0; } -/* Return nonzero if expression X refers to a REG or to memory - that is set in an instruction more recent than FROM_LUID. */ - -static int -use_crosses_set_p (const_rtx x, int from_luid) -{ - const char *fmt; - int i; - enum rtx_code code = GET_CODE (x); - - if (code == REG) - { - unsigned int regno = REGNO (x); - unsigned endreg = END_REGNO (x); - -#ifdef PUSH_ROUNDING - /* Don't allow uses of the stack pointer to be moved, - because we don't know whether the move crosses a push insn. */ - if (regno == STACK_POINTER_REGNUM && PUSH_ARGS) - return 1; -#endif - for (; regno < endreg; regno++) - { - reg_stat_type *rsp = ®_stat[regno]; - if (rsp->last_set - && rsp->last_set_label == label_tick - && DF_INSN_LUID (rsp->last_set) > from_luid) - return 1; - } - return 0; - } - - if (code == MEM && mem_last_set > from_luid) - return 1; - - fmt = GET_RTX_FORMAT (code); - - for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) - { - if (fmt[i] == 'E') - { - int j; - for (j = XVECLEN (x, i) - 1; j >= 0; j--) - if (use_crosses_set_p (XVECEXP (x, i, j), from_luid)) - return 1; - } - else if (fmt[i] == 'e' - && use_crosses_set_p (XEXP (x, i), from_luid)) - return 1; - } - return 0; -} - /* Define three variables used for communication between the following routines. */ -- 2.30.2