[Bug target/55023] New: hppa: wrong code generated with tail call optimisation

["mans at mansr dot com" <gcc-bugzilla at gcc dot gnu dot org>]

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