[Bug c/27308] New: Compiler generates incorrect code when calling a function with the result of an inline function as parameter

[Bug c/27308] New: Compiler generates incorrect code when calling a function with the result of an inline function as parameter

[Eric dot Doenges at betty-tv dot com]

Consider the following code:


typedef unsigned int  UINT32;
typedef unsigned char BOOL;
#define __SWI_BIOS_ContainerUsage  1234

#define __swicall1(type,name,type1,arg1)                         \
  static inline type name(type1 arg1) {                               \
    register long __r0 __asm__ ("r0") = (long)arg1;              \
    register long __res __asm__ ("r0");                                 \
    __asm__ __volatile__ ("swi\t%2\n\t"                               \
                          : "=r" (__res)                                       
    \
                          : "0" (__r0), "i" (__SWI_##name)                \
                          : "r1", "r2", "r3", "ip", "lr", "cc",                
\
                            "memory");                                         
 \
    return((type)__res);                                                      
\
  }
__swicall1(UINT32,BIOS_ContainerUsage,BOOL,verbose);
int sprintf(char *p, const char *frmt, ...);

void testme(char *tmp)
{
  sprintf(tmp, " %d%% Containers\n", BIOS_ContainerUsage(1));
  sprintf(tmp, " %d%% Containers\n", 2 * BIOS_ContainerUsage(1));
}

For the first call to sprintf, gcc generates the following assembler code:

        mov     r0, #1
        swi     #1234

        ldr     r5, .L3
        mov     r0, r4
        mov     r1, r5
        mov     r2, r4
        bl      sprintf

This is clearly wrong, since r2 should hold the result of the swi (which is
returned in r0). For the
second call to sprintf, gcc generates correct code:

        mov     r0, #1
        swi     #1234

        mov     r2, r0, asl #1
        mov     r1, r5
        mov     r0, r4
        ldmfd   sp!, {r4, r5, lr}
        b       sprintf


-- 
           Summary: Compiler generates incorrect code when calling a
                    function with the result of an inline function as
                    parameter
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: blocker
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: Eric dot Doenges at betty-tv dot com
  GCC host triplet: powerpc-apple-darwin8.5.0
GCC target triplet: arm-elf-unknown


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27308

[Bug c/27308] Compiler generates incorrect code when calling a function with the result of an inline function as parameter

[rguenth at gcc dot gnu dot org]

------- Comment #1 from rguenth at gcc dot gnu dot org  2006-04-25 12:38 -------
*** Bug 27305 has been marked as a duplicate of this bug. ***


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27308

[Bug c/27308] Compiler generates incorrect code when calling a function with the result of an inline function as parameter

[rguenth at gcc dot gnu dot org]

------- Comment #2 from rguenth at gcc dot gnu dot org  2006-04-25 12:49 -------
This is probably a problem with the inline asm constraints.  Try removing the
__asm__("r0") from the __res variable.  Also try simplifying the testcase by
storing the result of BIOS_ContainerUsage(1) to memory rather than calling
printf.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27308

[Bug c/27308] Compiler generates incorrect code when calling a function with the result of an inline function as parameter

[Eric dot Doenges at betty-tv dot com]

------- Comment #3 from Eric dot Doenges at betty-tv dot com  2006-04-25 14:37 -------
Storing the result to memory generates correct code


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27308

[Bug c/27308] Compiler generates incorrect code when calling a function with the result of an inline function as parameter

[Eric dot Doenges at betty-tv dot com]

------- Comment #4 from Eric dot Doenges at betty-tv dot com  2006-04-25 14:43 -------
Removing the __asm__ ("r0") from __res works around the bug - but then I cannot
depend on gcc
always allocating r0 for __res, can I ? I found no other way to tell gcc which
registers it must use.
I'm assuming this is a bug in gcc, not the asm constraint, because the same
code works flawlessly with
gcc-3.4.3.

As to simplifying the testcase - storing the result of BIOS_ContainerUsage to
memory generates correct
code regardless of wether __res is forced to r0 or not, making it worthless as
a test case.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27308

[Bug c/27308] Compiler generates incorrect code when calling a function with the result of an inline function as parameter

[rguenth at gcc dot gnu dot org]

------- Comment #5 from rguenth at gcc dot gnu dot org  2006-04-25 15:45 -------
__res should be allocated to the same register as __r0 due to the '0'
constraint which tells gcc to use the same register as for "=r" (__res). 
Whoops - I obviously meant to remove the __asm__("r0") from the __r0
variable...  But maybe it works vice-versa, too.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27308

[Bug target/27308] Compiler generates incorrect code when calling a function with the result of an inline function as parameter

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|blocker                     |normal


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27308

[Bug target/27308] Compiler generates incorrect code when calling a function with the result of an inline function as parameter

[Eric dot Doenges at betty-tv dot com]

------- Comment #6 from Eric dot Doenges at betty-tv dot com  2006-04-26 06:26 -------
Unfortunately, removing the __asm__ ("r0") from __r0 does not circumvent the
problem.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27308

[Bug target/27308] Compiler generates incorrect code when calling a function with the result of an inline function as parameter

[ramana at gcc dot gnu dot org]

------- Comment #7 from ramana at gcc dot gnu dot org  2009-05-12 09:36 -------
Confirmed with r147377


-- 

ramana at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2009-05-12 09:36:02
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27308

[Bug target/27308] Compiler generates incorrect code when calling a function with the result of an inline function as parameter

[ramana at gcc dot gnu dot org]

------- Comment #8 from ramana at gcc dot gnu dot org  2010-01-10 00:12 -------
Can't see this problem  with -O2 on trunk , 4.3 branch and 4.4 branch. I tried
with -mcpu=arm7tdmi


-- 

ramana at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |WAITING
   Target Milestone|---                         |4.3.5


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27308

[Bug target/27308] Compiler generates incorrect code when calling a function with the result of an inline function as parameter

[rguenth at gcc dot gnu dot org]

------- Comment #9 from rguenth at gcc dot gnu dot org  2010-05-22 18:11 -------
GCC 4.3.5 is being released, adjusting target milestone.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.3.5                       |4.3.6


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27308