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.
