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* Re: inline-asm/10857: Inlining a function with inline-asm: "error: impossible constraint in `asm'"
@ 2003-05-21  9:46 Bernd Trog
  0 siblings, 0 replies; 5+ messages in thread
From: Bernd Trog @ 2003-05-21  9:46 UTC (permalink / raw)
  To: nobody; +Cc: gcc-prs

The following reply was made to PR inline-asm/10857; it has been noted by GNATS.

From: Bernd Trog <berndtrog@yahoo.com>
To: jh@suse.cz, ehrhardt@mathematik.uni-ulm.de, gcc-bugs@gcc.gnu.org,
  gcc-prs@gcc.gnu.org, nobody@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Cc:  
Subject: Re: inline-asm/10857: Inlining a function with inline-asm: "error: impossible constraint in `asm'"
Date: Wed, 21 May 2003 02:38:42 -0700 (PDT)

 --- ehrhardt@mathematik.uni-ulm.de wrote:
 >     The patch the prevented this from compiling at -O3 went into gcc-3.4
 >     between 20030331 and 20030519.
 
 After spending some CPU cycles on compiling gcc, it looks like:
 
 +Fri Apr 11 00:12:14 CEST 2003  Jan Hubicka  <jh@suse.cz>
 +
 +       PR inline-asm/8803
 +       * function.c (instantate_virtual_regs):  Verify that all ASM
 statements
 +       match after the virutal regs instantiation.
 +
 
 
 gcc/gcc/function.c:
 
           instantiate_virtual_regs_1 (&CALL_INSN_FUNCTION_USAGE (insn),
                                       NULL_RTX, 0);
 +       
 +       /* Past this point all ASM statements should match.  Verify that
 +          to avoid failures later in the compilation process.  */
 +        if (asm_noperands (PATTERN (insn)) >= 0
 +           && ! check_asm_operands (PATTERN (insn)))
 +          instantiate_virtual_regs_lossage (insn);
        }
 
 triggered my regression.
 
 Removing that patch from 3.3.0 makes my code compile
 again - I'm happy :-)
 
 Maybe its possible to add another condition to that if statement?
 
 
 
 
 
 
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^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: inline-asm/10857: Inlining a function with inline-asm: "error: impossible constraint in `asm'"
@ 2003-05-19 17:53 ehrhardt
  0 siblings, 0 replies; 5+ messages in thread
From: ehrhardt @ 2003-05-19 17:53 UTC (permalink / raw)
  To: berndtrog, gcc-bugs, gcc-prs, nobody

Synopsis: Inlining a function with inline-asm: "error: impossible constraint in `asm'"

State-Changed-From-To: closed->open
State-Changed-By: cae
State-Changed-When: Mon May 19 17:53:20 2003
State-Changed-Why:
    Reopened based on submitter's comment. This is rejected by 3.3 at all
    optimization levels. I still don't think this should compile but previous
    versions of gcc accepted it. An arch independant example is below. Could
    someone please clarify if this supposed to compile at e.g. -S -O3?
    
    ----------------- cut -------------------------------
    #define PORTD 0x12
    
    static
    void
    write_byte(unsigned char adr, unsigned char data )
    {
    	__asm__ ("blah %0" : : "i" (adr));
    }
    
    int main(void)
    {
    	write_byte( PORTD, 4);
    	return 0;
    }
    ----------------- cut -------------------------------
    
    Both gcc-3.2 and older versions of gcc-3.4 accepted this if
    optimization level was high enough. It is rejected by gcc 3.3
    nomatter what. Note that __builtin_constant_p (adr) holds for
    the inlined copy of write_byte.
    
    The patch the prevented this from compiling at -O3 went into gcc-3.4
    between 20030331 and 20030519.
    
        regards  Christian

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=10857


^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: inline-asm/10857: Inlining a function with inline-asm: "error: impossible constraint in `asm'"
@ 2003-05-19 16:06 Bernd Trog
  0 siblings, 0 replies; 5+ messages in thread
From: Bernd Trog @ 2003-05-19 16:06 UTC (permalink / raw)
  To: nobody; +Cc: gcc-prs

The following reply was made to PR inline-asm/10857; it has been noted by GNATS.

From: Bernd Trog <berndtrog@yahoo.com>
To: ehrhardt@mathematik.uni-ulm.de, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org,
  nobody@gcc.gnu.org, gcc-gnats@gcc.gnu.org
Cc:  
Subject: Re: inline-asm/10857: Inlining a function with inline-asm: "error: impossible constraint in `asm'"
Date: Mon, 19 May 2003 09:00:08 -0700 (PDT)

 > You can request these optimizations with the various -O
 > flags and in this case the code compiles.
 
 Not for me. (gcc-3.3.0, tried: -Os, -O1, -O3) 
 
 Would you please describe your environment?
 
 The code compiles on gcc version 3.3 20030127 (prerelease). (with
 inline-asm warnings)
 
 
 
 
 
 
 
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^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: inline-asm/10857: Inlining a function with inline-asm: "error: impossible constraint in `asm'"
@ 2003-05-19 12:23 ehrhardt
  0 siblings, 0 replies; 5+ messages in thread
From: ehrhardt @ 2003-05-19 12:23 UTC (permalink / raw)
  To: berndtrog, gcc-bugs, gcc-prs, nobody

Synopsis: Inlining a function with inline-asm: "error: impossible constraint in `asm'"

State-Changed-From-To: open->closed
State-Changed-By: cae
State-Changed-When: Mon May 19 12:23:16 2003
State-Changed-Why:
    Not a bug. An immediate value must be a compile time constant. A
    procedure parameter is definitly NOT a compile time constant. gcc
    can deduce its value for an inline function if certain optimizations
    are done. You can request these optimizations with the various -O
    flags and in this case the code compiles. Note that there is no
    guarantee that this will remain true in the future.
    
    Also note that the `I' constraint has this description on the avr
    architecture:
    
    |    `I'
    |          Constant greater than -1, less than 64
    
         regards  Christian

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=10857


^ permalink raw reply	[flat|nested] 5+ messages in thread
* inline-asm/10857: Inlining a function with inline-asm: "error: impossible constraint in `asm'"
@ 2003-05-19 11:16 berndtrog
  0 siblings, 0 replies; 5+ messages in thread
From: berndtrog @ 2003-05-19 11:16 UTC (permalink / raw)
  To: gcc-gnats


>Number:         10857
>Category:       inline-asm
>Synopsis:       Inlining a function with inline-asm: "error: impossible constraint in `asm'"
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon May 19 11:16:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     Bernd Trog
>Release:        gcc-3.3.0
>Organization:
>Environment:
avr-gcc -v           
Reading specs from /src/build/gcc-330/lib/gcc-lib/avr/3.3/specs
Configured with: /src/gcc-330/configure -v --target=avr --prefix=/src/build/gcc-330 --with-gnu-ld --with-gnu-as --disable-nls --enable-languages=c,ada
Thread model: single
gcc version 3.3
>Description:
$ avr-gcc  test.c
test.c: In function `write_byte':
test.c:8: warning: asm operand 0 probably doesn't match constraints
test.c:8: error: impossible constraint in `asm'


Note: The information for operand 0 is available 
at compile-time(#define PORTD 0x12)!
>How-To-Repeat:
#define PORTD 0x12

static
inline
void
write_byte( unsigned char adr, unsigned char data )
{
    asm("out %0, %1" : : "I" (adr), "r" (data)  );
}

int main(void)
{
  write_byte( PORTD, 4);

  return 0;
}
>Fix:
unknown
>Release-Note:
>Audit-Trail:
>Unformatted:


^ permalink raw reply	[flat|nested] 5+ messages in thread

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