optimization/5075: sh-elf target optimize worse, save pr in leaf function

[bero@bekkoame.ne.jp]

>Number:         5075
>Category:       optimization
>Synopsis:       sh-elf target optimize worse, save pr in leaf function
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Dec 11 08:06:00 PST 2001
>Closed-Date:
>Last-Modified:
>Originator:     Takahiro Ishio
>Release:        3.0.2
>Organization:
>Environment:
gcc-3.0.2,cross target for sh-elf,host cygwin on windows2000
Configured with: ../gcc-3.0.2/configure --target=sh-elf --with-gnu-as --with-gnu
-ld --enable-language=c,c++ --with-newlib
>Description:
sh-elf target optimize worse,
save pr in leaf function

for example,-O2 -fomit-frame-pointer

int func(int a,int b)
{
  return a+b;
}

3.0.1 or before
	mov	r4,r0
	rts	
	add	r5,r0

3.0.2
	sts.l	pr,@-r15
	mov	r4,r0
	lds.l	@r15+,pr
	rts	
	add	r5,r0
>How-To-Repeat:

>Fix:

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