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| author | Richard Kenner <kenner@vlsi1.ultra.nyu.edu> | 2004-02-12 20:48:21 +0000 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 2004-02-12 15:48:21 -0500 |
| commit | 8fbc67c07219646fae89ab556738fe89ec3a8cda (patch) | |
| tree | ae858341fd9a06eaed05e5227868eec8273bc89c /gcc/function.c | |
| parent | a90a16f329ef47c800e3627ca4c2a9d38b176bd0 (diff) | |
| download | gcc-8fbc67c07219646fae89ab556738fe89ec3a8cda.tar.gz | |
* function.c (update_epilogue_consts): Teach about binary operations.
From-SVN: r77727
Diffstat (limited to 'gcc/function.c')
| -rw-r--r-- | gcc/function.c | 30 |
1 files changed, 27 insertions, 3 deletions
diff --git a/gcc/function.c b/gcc/function.c index ca26cf82517..d51edde1a1a 100644 --- a/gcc/function.c +++ b/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. */ |