From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-488286-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 121444 invoked by alias); 7 Jun 2015 22:03:48 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
Received: (qmail 121410 invoked by uid 48); 7 Jun 2015 22:03:44 -0000
From: "vries at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/66444] [5/6 Regression] Miscompilation of Xen since r211078
Date: Sun, 07 Jun 2015 22:03:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: rtl-optimization
X-Bugzilla-Version: 5.1.1
X-Bugzilla-Keywords: wrong-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: vries at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution:
X-Bugzilla-Priority: P1
X-Bugzilla-Assigned-To: vries at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 5.2
X-Bugzilla-Flags:
X-Bugzilla-Changed-Fields: assigned_to
Message-ID: <bug-66444-4-L8rR2hmpzQ@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-66444-4@http.gcc.gnu.org/bugzilla/>
References: <bug-66444-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2015-06/txt/msg00618.txt.bz2

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66444

vries at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |vries at gcc dot gnu.org

--- Comment #1 from vries at gcc dot gnu.org ---
Tentative patch:
...
diff --git a/gcc/postreload.c b/gcc/postreload.c
index 7ecca15..1cc7b14 100644
--- a/gcc/postreload.c
+++ b/gcc/postreload.c
@@ -1352,9 +1352,12 @@ reload_combine (void)
       if (CALL_P (insn))
        {
          rtx link;
+         HARD_REG_SET used_regs;
+
+         get_call_reg_set_usage (insn, &used_regs, call_used_reg_set);

          for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
-           if (call_used_regs[r])
+           if (TEST_HARD_REG_BIT (used_regs, r))
              {
                reg_state[r].use_index = RELOAD_COMBINE_MAX_USES;
                reg_state[r].store_ruid = reload_combine_ruid;
...

Output with patch:
...
        movabsq $962072674304, %r8
        salq    $5, %rax
        addq    %rax, %r8
        movq    %r8, %rdi
        call    fn1
        movq    %r8, %rdi
        call    fn2
...