From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-404301-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 21997 invoked by alias); 22 Oct 2012 14:39:26 -0000
Received: (qmail 21922 invoked by uid 48); 22 Oct 2012 14:39:09 -0000
From: "mans at mansr dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/55023] New: hppa: wrong code generated with tail call optimisation
Date: Mon, 22 Oct 2012 14:39:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: target
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: mans at mansr dot com
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Changed-Fields:
Message-ID: <bug-55023-4@http.gcc.gnu.org/bugzilla/>
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
Content-Type: text/plain; charset="UTF-8"
MIME-Version: 1.0
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
X-SW-Source: 2012-10/txt/msg01977.txt.bz2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55023

             Bug #: 55023
           Summary: hppa: wrong code generated with tail call optimisation
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mans@mansr.com


The following code is compiled incorrectly with flags -O2 -fno-inline: the
third argument to the tail called function is not computed at all.  This
problem is present in all versions since 4.3.  4.1 and 4.2 compile it
correctly.

The error -fno-inline flag is needed to suppress inlining of the called
function; when inlined it is compiled correctly.  Providing only an external
declaration for foo() also gives correct results.

---8<---
typedef long long int64_t;

struct foo {
    int x;
    int y;
};

int64_t foo(int64_t a, int64_t b, int64_t c)
{
    return a + b + c;
}

int64_t bar(int64_t a, struct foo bq, struct foo cq)
{
    int64_t b = bq.x + bq.y;
    int64_t c = cq.x + cq.y;
    return foo(a, b, c);
}
--->8---

This is the generated code:

    .align 4
.globl bar
    .type    bar, @function
bar:
    .PROC
    .CALLINFO FRAME=0,NO_CALLS,SAVE_RP
    .ENTRY
    stw %r23,-48(%r30)
    stw %r24,-44(%r30)
    ldw -44(%r30),%r28
    stw %r2,-20(%r30)
    ldw -48(%r30),%r24
    addl %r24,%r28,%r24
    extrs %r24,0,1,%r23
    ldw -20(%r30),%r2
    bl foo,%r0
    nop
    nop
    .EXIT
    .PROCEND