[Bug target/64876] Regressions in gcc-testresults for powerpc64 gccgo in 5.0 due to change for static chain for closures (219776)

["amodra at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64876

Alan Modra <amodra at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
          Component|go                          |target
           Assignee|ian at airs dot com                |amodra at gmail dot com

--- Comment #5 from Alan Modra <amodra at gmail dot com> ---
Oh yeah, this is really an rs6000 backend bug, not a go bug.  In 185.r.expand I
see

;; _12 = _11 (); [static-chain: _9]

(insn 78 77 79 (set (reg:DI 11 11)
        (reg/f:DI 181 [ D.1382 ]))
/home/amodra/src/gcc-virgin/gcc/testsuite/go.test/test/escape.go:155 -1
     (nil))

So there's the static chain being loaded.  Trouble is, indirect calls on ELFv1
load r11 from the function descriptor so the proper value is overwritten..

(insn 79 78 80 (set (mem/v/c:DI (plus:DI (reg/f:DI 1 1)
                (const_int 40 [0x28])) [28  S8 A8])
        (reg:DI 2 2))
/home/amodra/src/gcc-virgin/gcc/testsuite/go.test/test/escape.go:155 -1
     (nil))

(insn 80 79 81 (set (reg:DI 198)
        (mem:DI (reg/f:DI 182 [ D.1381 ]) [0  S8 A8]))
/home/amodra/src/gcc-virgin/gcc/testsuite/go.test/test/escape.go:155 -1
     (nil))

(insn 81 80 82 (set (reg:DI 11 11)
        (mem:DI (plus:DI (reg/f:DI 182 [ D.1381 ])
                (const_int 16 [0x10])) [0  S8 A8]))
/home/amodra/src/gcc-virgin/gcc/testsuite/go.test/test/escape.go:155 -1
     (nil))

..above.

(call_insn 82 81 83 (parallel [
            (set (reg:DI 3 3)
                (call (mem:SI (reg:DI 198) [0 *_11 S4 A8])
                    (const_int 64 [0x40])))
            (use (mem:DI (plus:DI (reg/f:DI 182 [ D.1381 ])
                        (const_int 8 [0x8])) [0  S8 A8]))
            (set (reg:DI 2 2)
                (unspec:DI [
                        (const_int 40 [0x28])
                    ] UNSPEC_TOCSLOT))
            (clobber (reg:DI 65 lr))
        ]) /home/amodra/src/gcc-virgin/gcc/testsuite/go.test/test/escape.go:155
-1
     (expr_list:REG_CALL_DECL (nil)
        (nil))
    (expr_list (use (reg:DI 11 11))
        (expr_list (use (reg:DI 11 11))
            (nil))))

Thus the patch to clear TARGET_POINTERS_TO_NESTED_FUNCTIONS which turns off
loading of r11 from function descriptors.