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reg-stack.c (subst_stack_regs): Pop the stack register for a computed goto which sets the same stack register.

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* reg-stack.c (subst_stack_regs): Pop the stack register for a
        computed goto which sets the same stack register.

        * reg-stack.c (compare_for_stack_reg): Swap only if the source and
        destination are both on the regstack.
        (subst_stack_regs_pat): Put the destination at the top of the regstack.
Bring over regstack bugfixes from the FSF.

From-SVN: r15096
This commit is contained in:
Stan Cox 1997-09-05 05:14:46 +00:00 committed by Jeff Law
parent d5d1738a3a
commit 914ec131d6
2 changed files with 59 additions and 9 deletions
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9
gcc/ChangeLog
View File

@ -1,3 +1,12 @@
Thu Sep 4 23:14:27 1997 Stan Cox (coxs@dg-rtp.dg.com)
* reg-stack.c (subst_stack_regs): Pop the stack register for a
computed goto which sets the same stack register.
* reg-stack.c (compare_for_stack_reg): Swap only if the source and
destination are both on the regstack.
(subst_stack_regs_pat): Put the destination at the top of the regstack.
Thu Sep 4 15:02:27 1997 Jim Wilson <wilson@cygnus.com>
* mips.md (nonlocal_goto_receiver): Define.

59
gcc/reg-stack.c
View File

@ -1,5 +1,5 @@
/* Register to Stack convert for GNU compiler.
Copyright (C) 1992, 1993, 1994, 1995, 1996 Free Software Foundation, Inc.
Copyright (C) 1992, 93, 94, 95, 96, 1997 Free Software Foundation, Inc.
This file is part of GNU CC.
@ -2018,6 +2018,7 @@ compare_for_stack_reg (insn, regstack, pat)
rtx *src1, *src2;
rtx src1_note, src2_note;
rtx cc0_user;
int have_cmove;
src1 = get_true_reg (&XEXP (SET_SRC (pat), 0));
src2 = get_true_reg (&XEXP (SET_SRC (pat), 1));
@ -2032,11 +2033,16 @@ compare_for_stack_reg (insn, regstack, pat)
rtx *dest, src_note;
dest = get_true_reg (&SET_DEST (PATTERN (cc0_user)));
if (REGNO (*dest) != regstack->reg[regstack->top])
have_cmove = 1;
if (get_hard_regnum (regstack, *dest) >= FIRST_STACK_REG
&& REGNO (*dest) != regstack->reg[regstack->top])
{
emit_swap_insn (insn, regstack, *dest);
}
}
else
have_cmove = 0;
/* ??? If fxch turns out to be cheaper than fstp, give priority to
registers that die in this insn - move those to stack top first. */
@ -2071,7 +2077,8 @@ compare_for_stack_reg (insn, regstack, pat)
else
src2_note = NULL_RTX;
emit_swap_insn (insn, regstack, *src1);
if (! have_cmove)
emit_swap_insn (insn, regstack, *src1);
replace_reg (src1, FIRST_STACK_REG);
@ -2378,8 +2385,6 @@ subst_stack_regs_pat (insn, regstack, pat)
for (i = 1; i <= 2; i++)
if (src_note [i])
{
int regno = get_hard_regnum (regstack, XEXP (src_note [i], 0));
/* If the register that dies is not at the top of stack, then
move the top of stack to the dead reg */
if (REGNO (XEXP (src_note[i], 0))
@ -2397,13 +2402,15 @@ subst_stack_regs_pat (insn, regstack, pat)
replace_reg (&XEXP (src_note[i], 0), FIRST_STACK_REG);
regstack->top--;
}
}
SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
replace_reg (dest, FIRST_STACK_REG);
}
/* Make dest the top of stack. Add dest to regstack if not present. */
if (get_hard_regnum (regstack, *dest) < FIRST_STACK_REG)
regstack->reg[++regstack->top] = REGNO (*dest);
SET_HARD_REG_BIT (regstack->reg_set, REGNO (*dest));
replace_reg (dest, FIRST_STACK_REG);
break;
default:
@ -2719,6 +2726,7 @@ subst_stack_regs (insn, regstack)
{
register rtx *note_link, note;
register int i;
rtx head, jump, pat, cipat;
int n_operands;
if (GET_CODE (insn) == CALL_INSN)
@ -2790,6 +2798,39 @@ subst_stack_regs (insn, regstack)
if (GET_CODE (insn) == NOTE)
return;
/* If we are reached by a computed goto which sets this same stack register,
then pop this stack register, but maintain regstack. */
pat = single_set (insn);
if (pat != 0
&& INSN_UID (insn) <= max_uid
&& GET_CODE (block_begin[BLOCK_NUM(insn)]) == CODE_LABEL
&& GET_CODE (pat) == SET && STACK_REG_P (SET_DEST (pat)))
for (head = block_begin[BLOCK_NUM(insn)], jump = LABEL_REFS (head);
jump != head;
jump = LABEL_NEXTREF (jump))
{
cipat = single_set (CONTAINING_INSN (jump));
if (cipat != 0
&& GET_CODE (cipat) == SET
&& SET_DEST (cipat) == pc_rtx
&& uses_reg_or_mem (SET_SRC (cipat))
&& INSN_UID (CONTAINING_INSN (jump)) <= max_uid)
{
int from_block = BLOCK_NUM (CONTAINING_INSN (jump));
if (TEST_HARD_REG_BIT (block_out_reg_set[from_block],
REGNO (SET_DEST (pat))))
{
struct stack_def old;
bcopy (regstack->reg, old.reg, sizeof (old.reg));
emit_pop_insn (insn, regstack, SET_DEST (pat), emit_insn_before);
regstack->top += 1;
bcopy (old.reg, regstack->reg, sizeof (old.reg));
SET_HARD_REG_BIT (regstack->reg_set, REGNO (SET_DEST (pat)));
}
}
}
/* If there is a REG_UNUSED note on a stack register on this insn,
the indicated reg must be popped. The REG_UNUSED note is removed,
since the form of the newly emitted pop insn references the reg,