From: Richard Sandiford Date: Thu, 26 Oct 2017 16:12:09 +0000 (+0000) Subject: Make more use of df_read_modify_subreg_p X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=9eaf97d6d7f1511638fb9209b7acf30e8f26a060;p=gcc.git Make more use of df_read_modify_subreg_p This patch uses df_read_modify_subreg_p to check whether writing to a subreg would preserve some of the existing contents. This has the effect of putting more emphasis on the REGMODE_NATURAL_SIZE-based definition of whether something can be partially modified, instead of using UNITS_PER_WORD unconditionally. This becomes important for SVE, where UNITS_PER_WORD has no significance for subregs of multi-register LD2/ST2, LD3/ST3 and LD4/ST4 tuples. 2017-10-26 Richard Sandiford Alan Hayward David Sherwood gcc/ * caller-save.c (mark_referenced_regs): Use read_modify_subreg_p. * combine.c (find_single_use_1): Likewise. (expand_field_assignment): Likewise. (move_deaths): Likewise. * lra-constraints.c (simplify_operand_subreg): Likewise. (curr_insn_transform): Likewise. * lra.c (collect_non_operand_hard_regs): Likewise. (add_regs_to_insn_regno_info): Likewise. * rtlanal.c (reg_referenced_p): Likewise. (covers_regno_no_parallel_p): Likewise. Co-Authored-By: Alan Hayward Co-Authored-By: David Sherwood From-SVN: r254110 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 9cf528c4335..4d5c9d2c66a 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,18 @@ +2017-10-26 Richard Sandiford + Alan Hayward + David Sherwood + + * caller-save.c (mark_referenced_regs): Use read_modify_subreg_p. + * combine.c (find_single_use_1): Likewise. + (expand_field_assignment): Likewise. + (move_deaths): Likewise. + * lra-constraints.c (simplify_operand_subreg): Likewise. + (curr_insn_transform): Likewise. + * lra.c (collect_non_operand_hard_regs): Likewise. + (add_regs_to_insn_regno_info): Likewise. + * rtlanal.c (reg_referenced_p): Likewise. + (covers_regno_no_parallel_p): Likewise. + 2017-10-26 Richard Sandiford * wide-int-print.cc (print_hex): Loop based on extract_uhwi. diff --git a/gcc/caller-save.c b/gcc/caller-save.c index 7c787f75163..576a023b8a3 100644 --- a/gcc/caller-save.c +++ b/gcc/caller-save.c @@ -1034,10 +1034,7 @@ mark_referenced_regs (rtx *loc, refmarker_fn *mark, void *arg) /* If we're setting only part of a multi-word register, we shall mark it as referenced, because the words that are not being set should be restored. */ - && ((GET_MODE_SIZE (GET_MODE (*loc)) - >= GET_MODE_SIZE (GET_MODE (SUBREG_REG (*loc)))) - || (GET_MODE_SIZE (GET_MODE (SUBREG_REG (*loc))) - <= UNITS_PER_WORD)))) + && !read_modify_subreg_p (*loc))) return; } if (code == MEM || code == SUBREG) diff --git a/gcc/combine.c b/gcc/combine.c index d71e50fdefb..93adfc11be7 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -579,10 +579,7 @@ find_single_use_1 (rtx dest, rtx *loc) && !REG_P (SET_DEST (x)) && ! (GET_CODE (SET_DEST (x)) == SUBREG && REG_P (SUBREG_REG (SET_DEST (x))) - && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x)))) - + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD) - == ((GET_MODE_SIZE (GET_MODE (SET_DEST (x))) - + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD)))) + && !read_modify_subreg_p (SET_DEST (x)))) break; return find_single_use_1 (dest, &SET_SRC (x)); @@ -7361,15 +7358,12 @@ expand_field_assignment (const_rtx x) } } - /* A SUBREG between two modes that occupy the same numbers of words - can be done by moving the SUBREG to the source. */ + /* If the destination is a subreg that overwrites the whole of the inner + register, we can move the subreg to the source. */ else if (GET_CODE (SET_DEST (x)) == SUBREG /* We need SUBREGs to compute nonzero_bits properly. */ && nonzero_sign_valid - && (((GET_MODE_SIZE (GET_MODE (SET_DEST (x))) - + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD) - == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (x)))) - + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD))) + && !read_modify_subreg_p (SET_DEST (x))) { x = gen_rtx_SET (SUBREG_REG (SET_DEST (x)), gen_lowpart @@ -13993,10 +13987,7 @@ move_deaths (rtx x, rtx maybe_kill_insn, int from_luid, rtx_insn *to_insn, if (GET_CODE (dest) == ZERO_EXTRACT || GET_CODE (dest) == STRICT_LOW_PART || (GET_CODE (dest) == SUBREG - && (((GET_MODE_SIZE (GET_MODE (dest)) - + UNITS_PER_WORD - 1) / UNITS_PER_WORD) - == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))) - + UNITS_PER_WORD - 1) / UNITS_PER_WORD)))) + && !read_modify_subreg_p (dest))) { move_deaths (dest, maybe_kill_insn, from_luid, to_insn, pnotes); return; diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c index 6163d7d5056..c3bbfd7151f 100644 --- a/gcc/lra-constraints.c +++ b/gcc/lra-constraints.c @@ -1679,7 +1679,7 @@ simplify_operand_subreg (int nop, machine_mode reg_mode) bitmap_set_bit (&lra_subreg_reload_pseudos, REGNO (new_reg)); insert_before = (type != OP_OUT - || GET_MODE_SIZE (innermode) > GET_MODE_SIZE (mode)); + || read_modify_subreg_p (operand)); insert_after = (type != OP_IN); insert_move_for_subreg (insert_before ? &before : NULL, insert_after ? &after : NULL, @@ -4232,9 +4232,7 @@ curr_insn_transform (bool check_only_p) constraints. */ if (type == OP_OUT && (curr_static_id->operand[i].strict_low - || (GET_MODE_SIZE (GET_MODE (reg)) > UNITS_PER_WORD - && (GET_MODE_SIZE (mode) - < GET_MODE_SIZE (GET_MODE (reg)))))) + || read_modify_subreg_p (*loc))) type = OP_INOUT; loc = &SUBREG_REG (*loc); mode = GET_MODE (*loc); diff --git a/gcc/lra.c b/gcc/lra.c index 3122f2c2505..04acf884f1c 100644 --- a/gcc/lra.c +++ b/gcc/lra.c @@ -832,14 +832,12 @@ collect_non_operand_hard_regs (rtx *x, lra_insn_recog_data_t data, subreg_p = false; if (code == SUBREG) { + if (read_modify_subreg_p (op)) + subreg_p = true; op = SUBREG_REG (op); code = GET_CODE (op); if (GET_MODE_SIZE (mode) < GET_MODE_SIZE (GET_MODE (op))) - { - mode = GET_MODE (op); - if (GET_MODE_SIZE (mode) > REGMODE_NATURAL_SIZE (mode)) - subreg_p = true; - } + mode = GET_MODE (op); } if (REG_P (op)) { @@ -1427,14 +1425,12 @@ add_regs_to_insn_regno_info (lra_insn_recog_data_t data, rtx x, int uid, subreg_p = false; if (GET_CODE (x) == SUBREG) { + if (read_modify_subreg_p (x)) + subreg_p = true; x = SUBREG_REG (x); code = GET_CODE (x); if (GET_MODE_SIZE (mode) < GET_MODE_SIZE (GET_MODE (x))) - { - mode = GET_MODE (x); - if (GET_MODE_SIZE (mode) > REGMODE_NATURAL_SIZE (mode)) - subreg_p = true; - } + mode = GET_MODE (x); } if (REG_P (x)) { diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c index 560bfd43c1c..beb24ba573c 100644 --- a/gcc/rtlanal.c +++ b/gcc/rtlanal.c @@ -1124,10 +1124,7 @@ reg_referenced_p (const_rtx x, const_rtx body) && !REG_P (SET_DEST (body)) && ! (GET_CODE (SET_DEST (body)) == SUBREG && REG_P (SUBREG_REG (SET_DEST (body))) - && (((GET_MODE_SIZE (GET_MODE (SUBREG_REG (SET_DEST (body)))) - + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD) - == ((GET_MODE_SIZE (GET_MODE (SET_DEST (body))) - + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD))) + && !read_modify_subreg_p (SET_DEST (body))) && reg_overlap_mentioned_p (x, SET_DEST (body))) return 1; return 0; @@ -2017,20 +2014,16 @@ dead_or_set_p (const rtx_insn *insn, const_rtx x) return 1; } -/* Return TRUE iff DEST is a register or subreg of a register and - doesn't change the number of words of the inner register, and any - part of the register is TEST_REGNO. */ +/* Return TRUE iff DEST is a register or subreg of a register, is a + complete rather than read-modify-write destination, and contains + register TEST_REGNO. */ static bool covers_regno_no_parallel_p (const_rtx dest, unsigned int test_regno) { unsigned int regno, endregno; - if (GET_CODE (dest) == SUBREG - && (((GET_MODE_SIZE (GET_MODE (dest)) - + UNITS_PER_WORD - 1) / UNITS_PER_WORD) - == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest))) - + UNITS_PER_WORD - 1) / UNITS_PER_WORD))) + if (GET_CODE (dest) == SUBREG && !read_modify_subreg_p (dest)) dest = SUBREG_REG (dest); if (!REG_P (dest))