Hi,
this patch fixes a few glitches in the post-reload compare elimination pass,
most notably the slightly disturbing opening comment:
This pass assumes:
[...]
(1) All comparison patterns are represented as
[(set (reg:CC) (compare:CC (reg) (immediate)))]
the mode mismatch in before_dom_children:
rtx x, flags = gen_rtx_REG (src_mode, targetm.flags_regnum);
/* Generate new comparison for substitution. */
x = gen_rtx_COMPARE (new_mode, XEXP (src, 0), XEXP (src, 1));
x = gen_rtx_SET (VOIDmode, flags, x);
and the direct tests on flag_non_call_exceptions:
if (flag_non_call_exceptions)
eh_note = find_reg_note (insn, REG_EH_REGION, NULL);
[...]
/* Take care that it's in the same EH region. */
if (flag_non_call_exceptions
&& !rtx_equal_p (eh_note, last_cmp->eh_note))
goto dont_delete;
It also factors out the comparison logic in before_dom_children to avoid the
series of gotos.
Tested on a private port we're about to submit, OK for the mainline?
2014-11-28 Eric Botcazou <ebotcazou@adacore.com>
* compare-elim.c: Fix head comment.
(conforming_compare): Remove redundant test.
(can_eliminate_compare): New function extracted from...
(before_dom_children): ...here. Use it, replace direct uses of
flag_non_call_exceptions and tidy up.
(maybe_select_cc_mode): Tidy up.