Re: optimization/10877: [3.3/3.4 regression] miscompilation with -O3 -fPIC on x86

[Wolfgang Bangerth <bangerth@ices.utexas.edu>]

The following reply was made to PR optimization/10877; it has been noted by GNATS.

From: Wolfgang Bangerth <bangerth@ices.utexas.edu>
To: Andrew Pinski <pinskia@physics.uc.edu>
Cc: gcc-bugs@gcc.gnu.org, <lloyd@acm.jhu.edu>, <gcc-gnats@gcc.gnu.org>
Subject: Re: optimization/10877: [3.3/3.4 regression] miscompilation with
 -O3 -fPIC on x86
Date: Tue, 20 May 2003 10:26:37 -0500 (CDT)

 > It does not fail for me though on i686-pc-linux-gnu with GCC: 3.4  
 > 20030517 (experimental).
 > Or on i686-unkown-openbsd3.1 with gcc version 3.4 20030519  
 > (experimental).
 
 OK, I made the experiment -- and my small snippet still segfaults with 
 both 3.3 and 3.4 checked out an hour or so ago. This is the assembler 
 output I get on my system with present 3.4. I think I'm at a loss for 
 further explanations, but feel free to ask me if you think you have a 
 theory...
 
   W.
 
 
 	.file	"y.cc"
 .globl i
 	.bss
 	.align 4
 	.type	i, @object
 	.size	i, 4
 i:
 	.zero	4
 	.text
 	.align 2
 	.p2align 4,,15
 .globl _Z5get_xv
 	.type	_Z5get_xv, @function
 _Z5get_xv:
 .LFB4:
 	call	.LPR0
 	addl	$_GLOBAL_OFFSET_TABLE_, %eax
 	pushl	%ebp
 .LCFI0:
 	movl	i@GOT(%eax), %edx
 	movl	%esp, %ebp
 .LCFI1:
 	popl	%ebp
 	movl	(%edx), %eax
 	ret
 .LFE4:
 	.size	_Z5get_xv, .-_Z5get_xv
 	.align 2
 	.p2align 4,,15
 .globl main
 	.type	main, @function
 main:
 .LFB5:
 	pushl	%ebp
 .LCFI2:
 	movl	%esp, %ebp
 .LCFI3:
 	leal	-8(%ebp), %eax
 	pushl	%ebx
 .LCFI4:
 	subl	$4, %esp
 .LCFI5:
 	andl	$-16, %esp
 	call	.LPR3
 	addl	$_GLOBAL_OFFSET_TABLE_, %ebx
 	movl	i@GOT(%ebx), %ecx
 	movl	%eax, (%ecx)
 	call	_Z5get_xv@PLT
 	movl	-4(%ebp), %ebx
 	xorl	%eax, %eax
 	leave
 	ret
 .LFE5:
 	.size	main, .-main
 .LPR0:
 	movl	(%esp), %eax
 	ret
 .LPR3:
 	movl	(%esp), %ebx
 	ret
 	.ident	"GCC: (GNU) 3.4 20030520 (experimental)"