diff options
Diffstat (limited to 'gcc/regmove.c')
| -rw-r--r-- | gcc/regmove.c | 19 |
1 files changed, 11 insertions, 8 deletions
diff --git a/gcc/regmove.c b/gcc/regmove.c index e685fc08eb5..11a5c704dd4 100644 --- a/gcc/regmove.c +++ b/gcc/regmove.c @@ -1642,7 +1642,7 @@ find_matches (insn, matchp) } /* Try to replace output operand DST in SET, with input operand SRC. SET is - the only set in INSN. INSN has just been recgnized and constrained. + the only set in INSN. INSN has just been recognized and constrained. SRC is operand number OPERAND_NUMBER in INSN. DST is operand number MATCH_NUMBER in INSN. If BACKWARD is nonzero, we have been called in a backward pass. @@ -1737,11 +1737,11 @@ fixup_match_1 (insn, set, src, src_subreg, dst, backward, operand_number, if ((dst_note = find_regno_note (p, REG_DEAD, REGNO (dst))) && (GET_MODE (XEXP (dst_note, 0)) == GET_MODE (dst))) { - /* If an optimization is done, the flags for P may be changed. - Check that P is not in or ending the shadow of a live flags - register. Note that the `ending' part (p is a flags user) - means that we have to check the _previous_ insn. */ - if (GET_MODE (PREV_INSN (p)) != VOIDmode) + /* If we would be moving INSN, check that we won't move it + into the shadow of a live a live flags register. */ + /* ??? We only try to move it in front of P, although + we could move it anywhere between OVERLAP and P. */ + if (overlap && GET_MODE (PREV_INSN (p)) != VOIDmode) break; if (! src_note) @@ -1851,8 +1851,11 @@ fixup_match_1 (insn, set, src, src_subreg, dst, backward, operand_number, break; if (! src_note && reg_overlap_mentioned_p (src, PATTERN (p))) { - /* INSN was already checked to be movable when - we found no REG_DEAD note for src on it. */ + /* INSN was already checked to be movable wrt. the registers that it + sets / uses when we found no REG_DEAD note for src on it, but it + still might clobber the flags register. We'll have to check that + we won't insert it into the shadow of a live flags register when + we finally know where we are to move it. */ overlap = p; src_note = find_reg_note (p, REG_DEAD, src); } |