reload.c (find_reloads_address_1): Handle PLUS expressions resulting from register elimination as PRE_MODIFY /...
* reload.c (find_reloads_address_1): Handle PLUS expressions resulting from register elimination as PRE_MODIFY / POST_MODIFY increments. Do not attempt to handle MEM inside auto-inc expressions. * reload1.c (eliminate_regs_1): Do not attempt to handle elimination of a register modified by an auto-inc expression. However, do handle elimination of a register used as PRE_MODIFY / POST_MODIFY increment. (elimination_effects): Prohibit elimination of a register modified by an auto-inc expression. Disable register elimination rules whose target register is modified by an auto-inc expression with variable increment. From-SVN: r122318
This commit is contained in:
Ulrich Weigand
Ulrich Weigand
parent
ae19c0415c
commit
b098aaf2ae
3 changed files with 63 additions and 47 deletions
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@ -1,3 +1,16 @@
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2007-02-25 Ulrich Weigand <uweigand@de.ibm.com>
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* reload.c (find_reloads_address_1): Handle PLUS expressions resulting
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from register elimination as PRE_MODIFY / POST_MODIFY increments.
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Do not attempt to handle MEM inside auto-inc expressions.
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* reload1.c (eliminate_regs_1): Do not attempt to handle elimination
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of a register modified by an auto-inc expression. However, do handle
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elimination of a register used as PRE_MODIFY / POST_MODIFY increment.
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(elimination_effects): Prohibit elimination of a register modified
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by an auto-inc expression. Disable register elimination rules whose
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target register is modified by an auto-inc expression with variable
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increment.
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2007-02-25 Zdenek Dvorak <dvorakz@suse.cz>
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* tree-ssa-loop-niter.c (compute_estimated_nb_iterations): Fix
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51
gcc/reload.c
51
gcc/reload.c
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@ -5543,16 +5543,20 @@ find_reloads_address_1 (enum machine_mode mode, rtx x, int context,
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auto-modify by a constant then we could try replacing a pseudo
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register with its equivalent constant where applicable.
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We also handle the case where the register was eliminated
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resulting in a PLUS subexpression.
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If we later decide to reload the whole PRE_MODIFY or
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POST_MODIFY, inc_for_reload might clobber the reload register
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before reading the index. The index register might therefore
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need to live longer than a TYPE reload normally would, so be
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conservative and class it as RELOAD_OTHER. */
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if (REG_P (XEXP (op1, 1)))
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if (!REGNO_OK_FOR_INDEX_P (REGNO (XEXP (op1, 1))))
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find_reloads_address_1 (mode, XEXP (op1, 1), 1, code, SCRATCH,
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&XEXP (op1, 1), opnum, RELOAD_OTHER,
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ind_levels, insn);
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if ((REG_P (XEXP (op1, 1))
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&& !REGNO_OK_FOR_INDEX_P (REGNO (XEXP (op1, 1))))
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|| GET_CODE (XEXP (op1, 1)) == PLUS)
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find_reloads_address_1 (mode, XEXP (op1, 1), 1, code, SCRATCH,
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&XEXP (op1, 1), opnum, RELOAD_OTHER,
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ind_levels, insn);
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gcc_assert (REG_P (XEXP (op1, 0)));
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@ -5733,43 +5737,6 @@ find_reloads_address_1 (enum machine_mode mode, rtx x, int context,
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}
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return value;
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}
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else if (MEM_P (XEXP (x, 0)))
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{
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/* This is probably the result of a substitution, by eliminate_regs,
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of an equivalent address for a pseudo that was not allocated to a
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hard register. Verify that the specified address is valid and
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reload it into a register. */
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/* Variable `tem' might or might not be used in FIND_REG_INC_NOTE. */
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rtx tem ATTRIBUTE_UNUSED = XEXP (x, 0);
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rtx link;
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int reloadnum;
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/* Since we know we are going to reload this item, don't decrement
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for the indirection level.
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Note that this is actually conservative: it would be slightly
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more efficient to use the value of SPILL_INDIRECT_LEVELS from
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reload1.c here. */
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/* We can't use ADDR_TYPE (type) here, because we need to
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write back the value after reading it, hence we actually
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need two registers. */
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find_reloads_address (GET_MODE (x), &XEXP (x, 0),
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XEXP (XEXP (x, 0), 0), &XEXP (XEXP (x, 0), 0),
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opnum, type, ind_levels, insn);
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reloadnum = push_reload (x, NULL_RTX, loc, (rtx*) 0,
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context_reg_class,
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GET_MODE (x), VOIDmode, 0, 0, opnum, type);
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rld[reloadnum].inc
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= find_inc_amount (PATTERN (this_insn), XEXP (x, 0));
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link = FIND_REG_INC_NOTE (this_insn, tem);
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if (link != 0)
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push_replacement (&XEXP (link, 0), reloadnum, VOIDmode);
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return 1;
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}
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return 0;
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case TRUNCATE:
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@ -2548,6 +2548,30 @@ eliminate_regs_1 (rtx x, enum machine_mode mem_mode, rtx insn,
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case POST_INC:
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case PRE_DEC:
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case POST_DEC:
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/* We do not support elimination of a register that is modified.
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elimination_effects has already make sure that this does not
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happen. */
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return x;
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case PRE_MODIFY:
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case POST_MODIFY:
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/* We do not support elimination of a register that is modified.
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elimination_effects has already make sure that this does not
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happen. The only remaining case we need to consider here is
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that the increment value may be an eliminable register. */
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if (GET_CODE (XEXP (x, 1)) == PLUS
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&& XEXP (XEXP (x, 1), 0) == XEXP (x, 0))
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{
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rtx new = eliminate_regs_1 (XEXP (XEXP (x, 1), 1), mem_mode,
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insn, true);
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if (new != XEXP (XEXP (x, 1), 1))
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return gen_rtx_fmt_ee (code, GET_MODE (x), XEXP (x, 0),
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gen_rtx_PLUS (GET_MODE (x),
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XEXP (x, 0), new));
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}
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return x;
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case STRICT_LOW_PART:
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case NEG: case NOT:
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case SIGN_EXTEND: case ZERO_EXTEND:
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@ -2743,6 +2767,14 @@ elimination_effects (rtx x, enum machine_mode mem_mode)
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case POST_DEC:
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case POST_MODIFY:
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case PRE_MODIFY:
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/* If we modify the source of an elimination rule, disable it. */
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for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
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if (ep->from_rtx == XEXP (x, 0))
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ep->can_eliminate = 0;
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/* If we modify the target of an elimination rule by adding a constant,
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update its offset. If we modify the target in any other way, we'll
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have to disable the rule as well. */
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for (ep = reg_eliminate; ep < ®_eliminate[NUM_ELIMINABLE_REGS]; ep++)
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if (ep->to_rtx == XEXP (x, 0))
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{
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@ -2757,11 +2789,15 @@ elimination_effects (rtx x, enum machine_mode mem_mode)
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ep->offset += size;
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else if (code == PRE_INC || code == POST_INC)
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ep->offset -= size;
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else if ((code == PRE_MODIFY || code == POST_MODIFY)
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&& GET_CODE (XEXP (x, 1)) == PLUS
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&& XEXP (x, 0) == XEXP (XEXP (x, 1), 0)
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&& CONSTANT_P (XEXP (XEXP (x, 1), 1)))
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ep->offset -= INTVAL (XEXP (XEXP (x, 1), 1));
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else if (code == PRE_MODIFY || code == POST_MODIFY)
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{
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if (GET_CODE (XEXP (x, 1)) == PLUS
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&& XEXP (x, 0) == XEXP (XEXP (x, 1), 0)
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&& CONST_INT_P (XEXP (XEXP (x, 1), 1)))
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ep->offset -= INTVAL (XEXP (XEXP (x, 1), 1));
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else
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ep->can_eliminate = 0;
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}
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}
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/* These two aren't unary operators. */
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