On 03/26/2012 06:03 PM, Andreas Schwab wrote:
> Bernd Schmidt <ber...@codesourcery.com> writes:
>
>> Does 4.7 still have the failure at all?
>
> Yes, see PR52573.
Well, I still think having both REG_DEAD and REG_UNUSED for the same reg
is bogus, but fixing that causes trouble in reg-stack. It seems the path
of least resistance is to just cope with the situation in regrename.
The following seems to cure the problem with a 4.7 m68k cross. Also
bootstrapped and tested with -frename-registers enabled at -O2 on
x86_64-linux. Ok everywhere?
Bernd
PR rtl-optimization/52573
* regrename.c (build_def_use): Ignore REG_DEAD notes if there is a
REG_UNUSED for the same register.
Index: regrename.c
===================================================================
--- regrename.c (revision 189425)
+++ regrename.c (working copy)
@@ -1718,7 +1718,8 @@ build_def_use (basic_block bb)
/* Step 4: Close chains for registers that die here. */
for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
- if (REG_NOTE_KIND (note) == REG_DEAD)
+ if (REG_NOTE_KIND (note) == REG_DEAD
+ && !find_regno_note (insn, REG_UNUSED, REGNO (XEXP (note, 0))))
{
remove_from_hard_reg_set (&live_hard_regs,
GET_MODE (XEXP (note, 0)),
