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* function.c (update_epilogue_consts): Teach about binary operations.

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From-SVN: r77727
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Richard Kenner 2004-02-12 20:48:21 +00:00 committed by Richard Kenner
parent a90a16f329
commit 8fbc67c072
2 changed files with 29 additions and 3 deletions

2
gcc/ChangeLog

@ -30,6 +30,8 @@
2004-02-12 Richard Kenner <kenner@vlsi1.ultra.nyu.edu>
* function.c (update_epilogue_consts): Teach about binary operations.
* emit-rtl.c (set_mem_attributes_minus_bitpos): Don't kill
previous MEM_VOLATILE in REF.
* function.c (fixup_var_refs): Save volatile_ok and set to 1.

30
gcc/function.c

@ -7654,14 +7654,38 @@ static void
update_epilogue_consts (rtx dest, rtx x, void *data)
{
struct epi_info *p = (struct epi_info *) data;
rtx new;
if (GET_CODE (dest) != REG || REGNO (dest) >= FIRST_PSEUDO_REGISTER)
return;
else if (GET_CODE (x) == CLOBBER || ! rtx_equal_p (dest, SET_DEST (x))
|| GET_CODE (SET_SRC (x)) != CONST_INT)
/* If we are either clobbering a register or doing a partial set,
show we don't know the value. */
else if (GET_CODE (x) == CLOBBER || ! rtx_equal_p (dest, SET_DEST (x)))
p->const_equiv[REGNO (dest)] = 0;
else
/* If we are setting it to a constant, record that constant. */
else if (GET_CODE (SET_SRC (x)) == CONST_INT)
p->const_equiv[REGNO (dest)] = SET_SRC (x);
/* If this is a binary operation between a register we have been tracking
and a constant, see if we can compute a new constant value. */
else if ((GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == 'c'
|| GET_RTX_CLASS (GET_CODE (SET_SRC (x))) == '2')
&& GET_CODE (XEXP (SET_SRC (x), 0)) == REG
&& REGNO (XEXP (SET_SRC (x), 0)) < FIRST_PSEUDO_REGISTER
&& p->const_equiv[REGNO (XEXP (SET_SRC (x), 0))] != 0
&& GET_CODE (XEXP (SET_SRC (x), 1)) == CONST_INT
&& 0 != (new = simplify_binary_operation
(GET_CODE (SET_SRC (x)), GET_MODE (dest),
p->const_equiv[REGNO (XEXP (SET_SRC (x), 0))],
XEXP (SET_SRC (x), 1)))
&& GET_CODE (new) == CONST_INT)
p->const_equiv[REGNO (dest)] = new;
/* Otherwise, we can't do anything with this value. */
else
p->const_equiv[REGNO (dest)] = 0;
}
/* Emit an insn to do the load shown in p->equiv_reg_src, if needed. */