GCC bug on PowerPC with gcc 2.95.2?

[Cort Dougan <cort at fsmlabs dot com>]

gcc version 2.95.2 19991024 (release)

I've tried this hosted on a Linux/x86 system targeting a Linux/PPC system
and I've done a native build on a Linux/PPC host.

I've attached the program that demonstrates the problem.  The command line
was:

ppc-linux-gcc --save-temps gccbug.c

In the inline asm I change r1 but I tell gcc in the 'modifies' constraint
that I've changed it.  The output asm shows that it doesn't save/restore r1
during that code, though.

This seems like a bug but may be an undocumented feature of gcc.  It shows
this behavior with 2.95.2 (19991024) but I haven't tried others.

I'm including the .c, .s and .i.
#include <stdio.h>

int main(void)
{
		asm (
		     "/* inline asm cort junk */\n\t"
		     "mr	1,%0\n\t"
		     "/* end inline asm cort junk */\n\t"
		     : /* output */
		     : /* input */ "r" (0)
		     : /* modifies */ "r1" );

		{
			/* force a use of the stack - printf */
			int i = 0;
			printf("i %d\n", i);
		}
		return 0;
}
	.file	"gccbug.c"
gcc2_compiled.:
	.section	".rodata"
	.align 2
.LC0:
	.string	"i %d\n"
	.section	".text"
	.align 2
	.globl main
	.type	 main,@function
main:
	stwu 1,-32(1)
	mflr 0
	stw 31,28(1)
	stw 0,36(1)
	mr 31,1
	li 0,0
	/* inline asm cort junk */
	mr	1,0
	/* end inline asm cort junk */
	
	li 0,0
	stw 0,8(31)
	lis 9,.LC0@ha
	la 3,.LC0@l(9)
	lwz 4,8(31)
	crxor 6,6,6
	bl printf
	li 3,0
	b .L2
.L2:
	lwz 11,0(1)
	lwz 0,4(11)
	mtlr 0
	lwz 31,-4(11)
	mr 1,11
	blr
.Lfe1:
	.size	 main,.Lfe1-main
	.ident	"GCC: (GNU) 2.95.2 19991024 (release)"

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