diff options
Diffstat (limited to 'gcc/reload1.c')
| -rw-r--r-- | gcc/reload1.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/gcc/reload1.c b/gcc/reload1.c index 54d163ee00c..83456130534 100644 --- a/gcc/reload1.c +++ b/gcc/reload1.c @@ -9094,6 +9094,9 @@ static int move2add_last_label_luid; && TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (OUTMODE), \ GET_MODE_BITSIZE (INMODE)))) +/* The source of the last set to cc0 we've seen. */ +static rtx move2add_last_cc0; + static void reload_cse_move2add (first) rtx first; @@ -9106,6 +9109,7 @@ reload_cse_move2add (first) move2add_last_label_luid = 0; move2add_luid = 2; + move2add_last_cc0 = NULL_RTX; for (insn = first; insn; insn = NEXT_INSN (insn), move2add_luid++) { rtx pat, note; @@ -9288,6 +9292,29 @@ reload_cse_move2add (first) } } note_stores (PATTERN (insn), move2add_note_store, NULL); + + /* If INSN is a conditional branch, we try to extract an + implicit set out of it. */ + if (any_condjump_p (insn) && onlyjump_p (insn)) + { + rtx cnd = get_condition (insn, NULL); + +#ifdef HAVE_cc0 + if (cnd != NULL_RTX && move2add_last_cc0 != NULL_RTX) + cnd = simplify_replace_rtx (cnd, cc0_rtx, move2add_last_cc0); +#endif + if (cnd != NULL_RTX + && GET_CODE (cnd) == NE + && GET_CODE (XEXP (cnd, 0)) == REG + && SCALAR_INT_MODE_P (GET_MODE (XEXP (cnd, 0))) + && GET_CODE (XEXP (cnd, 1)) == CONST_INT) + { + rtx implicit_set = + gen_rtx_SET (VOIDmode, SET_DEST (cnd), SET_SRC (cnd)); + move2add_note_store (SET_DEST (implicit_set), implicit_set, 0); + } + } + /* If this is a CALL_INSN, all call used registers are stored with unknown values. */ if (GET_CODE (insn) == CALL_INSN) @@ -9334,6 +9361,13 @@ move2add_note_store (dst, set, data) reg_set_luid[REGNO (XEXP (dst, 0))] = 0; return; } + /* Note a store into cc0 so that we can later find an implicit + set. */ + if (CC0_P (dst)) + { + move2add_last_cc0 = SET_SRC (set); + return; + } if (GET_CODE (dst) != REG) return; |