[Bug middle-end/12081] New: Gcc can't be compiled with -mregparm=3

[Bug middle-end/12081] New: Gcc can't be compiled with -mregparm=3

[mikulas at artax dot karlin dot mff dot cuni dot cz]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12081

           Summary: Gcc can't be compiled with -mregparm=3
           Product: gcc
           Version: 3.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: mikulas at artax dot karlin dot mff dot cuni dot cz
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i586-pc-linux-gnu
  GCC host triplet: i586-pc-linux-gnu
GCC target triplet: i586-pc-linux-gnu

When GCC is compiled with -mregparm=3 (system libraries are compiled with that flag too), it doesn't work. The problem is this line (maybe there are more buggy declarations, but this is the first one I hit):

typedef rtx (*insn_gen_fn) PARAMS ((rtx, ...));

Later, two-parameter functions are retyped to insn_gen_fn and called. The caller pushes arguments to stack, the calee expects them in registers.

[Bug other/12081] Gcc can't be compiled with -mregparm=3

[pinskia at gcc dot gnu dot org]

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12081


pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
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          Component|middle-end                  |other

[Bug target/12081] Gcc can't be compiled with -mregparm=3

[pinskia at gcc dot gnu dot org]

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           What    |Removed                     |Added
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          Component|other                       |target


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12081

[Bug target/12081] Gcc can't be compiled with -mregparm=3

[dhazeghi at yahoo dot com]

------- Additional Comments From dhazeghi at yahoo dot com  2004-01-17 23:53 -------
Sorry that this report seems to have slipped through the cracks. What exactly do you mean by 
"doesn't work"? Does it produce buggy code, or just crash, or what? Also, I don't suppose you 
could come up with a small, self-contained testcase? Thanks.

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           What    |Removed                     |Added
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             Status|UNCONFIRMED                 |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12081

[Bug target/12081] Gcc can't be compiled with -mregparm=3

[mikulas at artax dot karlin dot mff dot cuni dot cz]

------- Additional Comments From mikulas at artax dot karlin dot mff dot cuni dot cz  2004-01-18 01:39 -------
Gcc is code written the wrong way

Let's have these declarations:

void f(int a, int b);
void (*g)(int a, ...);

and this code:

g = (void (*)(int, ...))f;
f(1,2);

--- the code is obviously wrong in C and might not work. It works on most
architectures, but it doesn't on x86 with regparm 3 or -mrtd.

Similar code exists in gcc in insn-output.c (there is:
"(insn_gen_fn)gen_cmpqi_ext_3_insn" and many more like this).

I "fixed" it for myself by adding attribute regparm(0),cdecl to these
functions, but it is not correct fix. Correct fix would be to not use these
kind of casts.

I can't show you how to reproduce the bug, because you don't have environment
where regparm(3) is default calling convention. I do have.


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           What    |Removed                     |Added
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             Status|WAITING                     |NEW


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12081

[Bug target/12081] Gcc can't be compiled with -mregparm=3

[mikulas at artax dot karlin dot mff dot cuni dot cz]

------- Additional Comments From mikulas at artax dot karlin dot mff dot cuni dot cz  2004-01-18 01:42 -------
In example I wrote there should be
g(1,2)
instead of
f(1,2)

f(1,2) is correct, but g(1,2) will crash with -mrtd or pass invalid arguments
with -mregparm=3.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12081

[Bug target/12081] Gcc can't be compiled with -mregparm=3

[dhazeghi at yahoo dot com]

------- Additional Comments From dhazeghi at yahoo dot com  2004-01-18 01:54 -------
I don't necessarily disagree. However without a testcase, the chances of somebody looking into/
fixing this aren't too good (I certainly don't have the expertise).

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12081

[Bug target/12081] Gcc can't be compiled with -mregparm=3

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-28 12:09 -------
*** Bug 18193 has been marked as a duplicate of this bug. ***

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                 CC|                            |rpedersen at atmel dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12081