From patchwork Mon Nov 12 08:36:23 2012
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Subject: [RFA,middle-end] Fix PR target/41993
Date: Sun, 11 Nov 2012 22:36:23 -0000
From: Uros Bizjak <ubizjak@gmail.com>
X-Patchwork-Id: 198330
Message-Id: <CAFULd4bNJounwyhgT3DgAJzPZ_iH-yZG-Z-rbRoJytD4M0UJJQ@mail.gmail.com>
To: Eric Botcazou <ebotcazou@adacore.com>
Cc: Kaz Kojima <kkojima@rr.iij4u.or.jp>, gcc-patches@gcc.gnu.org

On Tue, Nov 6, 2012 at 9:12 AM, Eric Botcazou <ebotcazou@adacore.com> wrote:
>> 2012-11-05  Uros Bizjak  <ubizjak@gmail.com>
>>           Kaz Kojima  <kkojima@gcc.gnu.org>
>>
>>       PR target/41993
>>       * mode-switching.c (create_pre_exit): Set return_copy to
>>       last_insn when copy_start is a pseudo reg.

It looks to me, that we in fact want:

--cut here--
--cut here--

If we find an unrelated HARD register, we will fail in the same way as
described in the PR. This was found by post-reload vzeroupper
insertion pass that tripped on unrelated hard reg assignment. At this
point, we are interested only in hard registers that are also used for
function return value. Actually, even in pre-reload pass, there are no
other assignments to hard registers.

Uros.


Index: mode-switching.c
===================================================================
--- mode-switching.c    (revision 193407)
+++ mode-switching.c    (working copy)
@@ -330,7 +330,7 @@
                          short_block = 1;
                        break;
                      }
-                   if (copy_start >= FIRST_PSEUDO_REGISTER)
+                   if (!targetm.calls.function_value_regno_p (copy_start))
                      {
                        last_insn = return_copy;
                        continue;