Re: target/3218: ARM/Thumb: Illegal byte-oriented stack instructions

Re: target/3218: ARM/Thumb: Illegal byte-oriented stack instructions

[Momchil Velikov]

The following reply was made to PR target/3218; it has been noted by GNATS.

From: Momchil Velikov <velco@fadata.bg>
To: pb@gcc.gnu.org
Cc: gcc-bugs@gcc.gnu.org, trauscher@loytec.com, gcc-gnats@gcc.gnu.org
Subject: Re: target/3218: ARM/Thumb: Illegal byte-oriented stack instructions
Date: 22 Jan 2002 13:23:17 +0200

 >>>>> "pb" == pb  <pb@gcc.gnu.org> writes:
 
 pb> Synopsis: ARM/Thumb: Illegal byte-oriented stack instructions
 pb> State-Changed-From-To: open->analyzed
 pb> State-Changed-By: pb
 pb> State-Changed-When: Tue Jan 22 03:12:10 2002
 pb> State-Changed-Why:
 pb>     Bug still exists with current 3.0 sources
 
 pb> http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=3218
 
 The thread starting here is relevent to this PR.
 
 http://gcc.gnu.org/ml/gcc-patches/2002-01/msg01263.html

Re: target/3218: ARM/Thumb: Illegal byte-oriented stack instructions

[rearnsha]

Synopsis: ARM/Thumb: Illegal byte-oriented stack instructions

Responsible-Changed-From-To: unassigned->rearnsha
Responsible-Changed-By: rearnsha
Responsible-Changed-When: Mon Sep 30 05:08:29 2002
Responsible-Changed-Why:
    .
State-Changed-From-To: analyzed->closed
State-Changed-By: rearnsha
State-Changed-When: Mon Sep 30 05:08:29 2002
State-Changed-Why:
    I've checked in a change that should solve this problem on both the trunk and 3.2 branch.  If you still get this problem with the fixed code then please resubmit.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=3218

Re: target/3218: ARM/Thumb: Illegal byte-oriented stack instructions

[pb]

Synopsis: ARM/Thumb: Illegal byte-oriented stack instructions

State-Changed-From-To: open->analyzed
State-Changed-By: pb
State-Changed-When: Tue Jan 22 03:12:10 2002
State-Changed-Why:
    Bug still exists with current 3.0 sources

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=3218

target/3218: ARM/Thumb: Illegal byte-oriented stack instructions

[trauscher]

>Number:         3218
>Category:       target
>Synopsis:       ARM/Thumb: Illegal byte-oriented stack instructions
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          wrong-code
>Submitter-Id:   net
>Arrival-Date:   Mon Jun 18 01:16:00 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Thomas Rauscher
>Release:        3.0 20010528 (prerelease)
>Organization:
LoyTec electronics
>Environment:
System: Linux lexx 2.2.17 #1 Thu Oct 12 11:50:54 CEST 2000 i686 unknown
Architecture: i686

	
host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: arm-rtems-elf
configured with: ./configure --prefix=/prj/rtems/test --target=arm-rtems-elf --enable-languages=c --with-newlib
>Description:
	Under some cirumstances (after some byte-oriented stack access), the compiler
        generates sp-relative strb instructions, which are not supported by 
        the Thumb instruction set. When the code is less complex than the example
        below, the sp register gets copied into an accessible low register before
        accessing the stack, so the problem only occurs in more complex functions.
        Switches: -mthumb -mbig-endian -mthumb-interwork -O3
>How-To-Repeat:
Preprocessor output:
# 16 "strb.c"
typedef struct
{
  char x1, x2, x3, x4, x5, *x6;
} s1;

typedef struct
{
  char x, y[8];
} s2;

extern int *a1;
extern s2 *a2;
void f1(void *p1, void *p2);

void f2(int n, char *p, int *out)
{
  s1 in;

  in.x1 = p[0];
  in.x2 = p[1];
  in.x3 = p[2];
  in.x4 = p[3];
  in.x5 = p[4];
  in.x6 = p;

  if(!in.x1)
  {
    f1(&a2[n].x, in.x1);
    f1(&a2[n].x, &a1[n]);
    if (n) *out = 0;
    if (in.x1) *out = 0;
  }
}
>Fix:
	Probably the thumb_movqi_insn should not contain the 
        ldrb/strb/ldrh/strh instructions in conjunction with
        the high registers for thumb mode.
>Release-Note:
>Audit-Trail:
>Unformatted: