[Bug target/38151] structures with _Complex arguments are not passed correctly

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

------- Comment #21 from ubizjak at gmail dot com  2008-11-22 12:33 -------
This is a trace what happens in the testcase, from .expand dump:

(2) [frame + 8 ]        <- si
(3) [frame + 16]        <- dx
(4) r62                 <- di

(8) r63                 <- virtual-incoming-args + 0
(9) r64                 <- virtual-stack-vars - 64
(10) [r64]              <- 8                            ;; gp_offset
(11) r65                <- virtual-stack-vars - 64
(12) [r65 + 8 ]         <- virtual-incoming-args        ;; overflow_arg_area
(13) r66                <- virtual-stack-vars - 64
(14) [r66 + 16]         <- frame                        ;; reg_save_area
(15) r61                <- [virtual-stack-vars - 64]    ;; gp_offset
if (r61 > 39)
   goto label 27

(19) r67                <- virtual-stack-vars - 32
(20) r68                <- zext (r61)
(21) r69                <- [virtual-stack-vars - 48]    ;; reg_save_area
(22) r70                <- [r69 + r68]
(23) [r67]              <- r70
(24) r58                <- virtual-stack-vars - 32
goto label 32

label 27:
(29) r72                <- [virtual-stack-vars - 56]    ;; overflow_arg_area
(30) r71                <- r72 + 15
(31) r58                <- r71 & -16

label 32:
(34) r73                <- [r58]
(35) [virtual-stack-vars - 16] <- r73
(36) r74                <- [r58 + 8]
(37) [virtual-stack-vars - 8 ] <- r74
(38) r60                <- [virual-stack-vars - 12]     ;; arg$b$real
(39) r59                <- [virual-stack-vars - 8 ]     ;; arg$b$imag

So, around insn (22), gcc forgets to copy dx register to reg_save_area. r74 is
then read from uninitialized reg_save_area slot.

I'm looking at va-arg handling implementation in i386.c. But I'm not familiar
with this code, so a bit of help would be most welcome here.


-- 

ubizjak at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|ubizjak at gmail dot com    |unassigned at gcc dot gnu
                   |                            |dot org
             Status|ASSIGNED                    |NEW


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38151