c++/2853: gcc-3.0 generates incorrect code for std::strchr() for i586-pc-msdosdjgp

c++/2853: gcc-3.0 generates incorrect code for std::strchr() for i586-pc-msdosdjgp

[pavenis]

>Number:         2853
>Category:       c++
>Synopsis:       gcc-3.0 generates incorrect code for std::strchr() for i586-pc-msdosdjgp
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          wrong-code
>Submitter-Id:   net
>Arrival-Date:   Thu May 17 01:36:00 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Andris Pavenis
>Release:        gcc-3.0 20010515 (prerelease)
>Organization:
>Environment:
target i586-pc-msdosdjgpp, binutils-2.11
>Description:
gcc-3.0 20010515 generates incorrect code for call to std::strchr when cstring is included (target i586-pc-msdosdjgpp). Here is test example I used:

#include <cstring>
char * findx (char * str) { return strchr (str,'x'); }

Preprocessed source, compiler output, assembler output and
output from objdump and nm are in attachment. Generated 
object file contains following code:

Disassembly of section .gnu.linkonce.t.strchr:

00000020 <strchr>:
  20:	55                   	push   %ebp
  21:	89 e5                	mov    %esp,%ebp
  23:	52                   	push   %edx
  24:	52                   	push   %edx
  25:	89 ec                	mov    %ebp,%esp
  27:	5d                   	pop    %ebp
  28:	e9 f3 ff ff ff       	jmp    20 <strchr>
  2d:	8d 76 00             	lea    0x0(%esi),%esi

Which causes infinite loop. After following patch to 
assembler source (generated by gcc) the problem seems to disappear:

-- foo.s~1	Thu May 17 11:05:16 2001
+++ foo.s	Thu May 17 11:05:38 2001
@@ -30,7 +30,7 @@
 LFE1:
 	.section .gnu.linkonce.t.strchr,"x"
 	.p2align 4
-	.def	_strchr;	.val	__ZSt6strchrPKci;	.scl	2;	.type	0142;	.endef
+	.def	__ZSt6strchrPKci;	.val	__ZSt6strchrPKci;	.scl	2;	.type	0142;	.endef
 	.weak	__ZSt6strchrPKci
 __ZSt6strchrPKci:
 LFB2:


I cannot reproduce this problem for i686-pc-linux-gnu

Andris
>How-To-Repeat:

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:
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