From c8e90f4053f0e366630c5147d28d4d9c56e56668 Mon Sep 17 00:00:00 2001 From: Eric Botcazou Date: Wed, 9 Nov 2005 21:34:31 +0000 Subject: ifcvt.c (noce_get_alt_condition): Use prev_nonnote_insn. * ifcvt.c (noce_get_alt_condition): Use prev_nonnote_insn. (noce_try_abs): Negate if the comparison is reversed. Look only one instruction backwards for a REG_EQUAL note. From-SVN: r106706 --- gcc/ifcvt.c | 37 ++++++++++++++++++++++--------------- 1 file changed, 22 insertions(+), 15 deletions(-) (limited to 'gcc/ifcvt.c') diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c index da32ab4..e7eec87 100644 --- a/gcc/ifcvt.c +++ b/gcc/ifcvt.c @@ -1485,7 +1485,7 @@ noce_get_alt_condition (struct noce_if_info *if_info, rtx target, rtx prev_insn; /* First, look to see if we put a constant in a register. */ - prev_insn = PREV_INSN (if_info->cond_earliest); + prev_insn = prev_nonnote_insn (if_info->cond_earliest); if (prev_insn && INSN_P (prev_insn) && GET_CODE (PATTERN (prev_insn)) == SET) @@ -1697,7 +1697,9 @@ noce_try_abs (struct noce_if_info *if_info) if (no_new_pseudos) return FALSE; - /* Recognize A and B as constituting an ABS or NABS. */ + /* Recognize A and B as constituting an ABS or NABS. The canonical + form is a branch around the negation, taken when the object is the + first operand of a comparison against 0 that evaluates to true. */ a = if_info->a; b = if_info->b; if (GET_CODE (a) == NEG && rtx_equal_p (XEXP (a, 0), b)) @@ -1718,25 +1720,30 @@ noce_try_abs (struct noce_if_info *if_info) if (rtx_equal_p (XEXP (cond, 0), b)) c = XEXP (cond, 1); else if (rtx_equal_p (XEXP (cond, 1), b)) - c = XEXP (cond, 0); + { + c = XEXP (cond, 0); + negate = !negate; + } else return FALSE; - /* Verify that C is zero. Search backward through the block for - a REG_EQUAL note if necessary. */ + /* Verify that C is zero. Search one step backward for a + REG_EQUAL note or a simple source if necessary. */ if (REG_P (c)) { - rtx insn, note = NULL; - for (insn = earliest; - insn != BB_HEAD (if_info->test_bb); - insn = PREV_INSN (insn)) - if (INSN_P (insn) - && ((note = find_reg_note (insn, REG_EQUAL, c)) - || (note = find_reg_note (insn, REG_EQUIV, c)))) - break; - if (! note) + rtx set, insn = prev_nonnote_insn (earliest); + if (insn + && (set = single_set (insn)) + && rtx_equal_p (SET_DEST (set), c)) + { + rtx note = find_reg_equal_equiv_note (insn); + if (note) + c = XEXP (note, 0); + else + c = SET_SRC (set); + } + else return FALSE; - c = XEXP (note, 0); } if (MEM_P (c) && GET_CODE (XEXP (c, 0)) == SYMBOL_REF -- cgit v1.1