(i386-linux x sh-elf) Unnecessary stack adjusts generated for function calls

[Toshiyasu Morita]

version: CVS
   host: i386-linux
 target: sh-elf

For some reason, gcc has started to generate unnecessary
stack adjusts before and after most function calls. 

For example, when the following code is compiled:

oid func(int foo)


{
        func2(foo);
}

using the options:

-O2 -m4-single-only -ml -S -g 

the following code is generated:

func:
        mov.l   r14,@-r15
        mov.l   .L3,r1
        sts.l   pr,@-r15
        mov     r15,r14
        jsr     @r1
        add     #-4,r15		<- unnecessary stack adjust
        mov     r14,r15
        lds.l   @r15+,pr
        rts
        mov.l   @r15+,r14

I initially noticed this while browsing the bzip2 decompressor output.
Here are a few samples from bzip2:

3032:./decompress.i ****       } else {
3033:./decompress.i ****          s->tt  = (strm->bzalloc)(strm->opaque,(  s->blockSize100k * 100000 * sizeof(Int32)  ),1) ;
 756 0380 46D1                  mov.l   .L704,r1
 757 0382 FC7F                  add     #-4,r15		<- here
 758 0384 D954                  mov.l   @(36,r13),r4
 759 0386 01E6                  mov     #1,r6
3034:./decompress.i ****          if (s->tt == ((void *)0) ) { retVal =  (-3)  ; goto save_state_and_return; }; ;
 762 0388 FDEA                  mov     #-3,r10
 765 038a 1702                  mul.l   r1,r2
 766 038c D751                  mov.l   @(28,r13),r1
 767 038e 0B41                  jsr     @r1
 768 0390 1A05                  sts     macl,r5
 769 0392 0361                  mov     r0,r1
...
3054:./decompress.i ****          fprintf(((_IO_FILE*)(&_IO_stderr_))  ,  "\n    [%d: huff+mtf " ,  s->currBlockNo  ) ;
 1136 0624 4ED1                 mov.l   .L707,r1
 1137 0626 4FD5                 mov.l   .L708,r5
 1138 0628 4FD4                 mov.l   .L709,r4
 1139 062a 0B41                 jsr     @r1
 1140 062c FC7F                 add     #-4,r15		<- here
 1141 062e 047F                 add     #4,r15		<- here
...
 1759                   .L183:
 1760 0a8c 017B                 add     #1,r11
 1761 0a8e 0FE1                 mov     #15,r1
 1762 0a90 173B                 cmp/gt  r1,r11
 1763 0a92 B18B                 bf      .L184
 1764 0a94 FC7F                 add     #-4,r15		<- here
3091:./decompress.i ****             }
3092:./decompress.i ****       makeMaps_d ( s );
 1767 0a96 2CD1                 mov.l   .L717,r1
 1768 0a98 0B41                 jsr     @r1
...
 3879 16da 9C51                 mov.l   @(48,r9),r1
 3880 16dc 2731                 cmp/gt  r2,r1
 3881 16de 058B                 bf      .L426
 3882 16e0 63D1                 mov.l   .L779,r1
 3883 16e2 64D5                 mov.l   .L780,r5
 3884 16e4 64D4                 mov.l   .L781,r4
 3885 16e6 0B41                 jsr     @r1
 3886 16e8 FC7F                 add     #-4,r15		<- here
 3887 16ea 047F                 add     #4,r15		<- here
 3888                   .L426:
3293:./decompress.i ****
3294:./decompress.i ****
3295:./decompress.i ****       s->cftab[0] = 0;
...
3326:./decompress.i ****              s->k0  = indexIntoF ( s->tPos, s->cftab ); s->tPos = (((UInt32)s->ll16[ s->tPos ]) | (
 4201 18b0 67D1                 mov.l   .L792,r1
 4202 18b2 FC7F                 add     #-4,r15		<- here
 4203 18b4 C695                 mov.w   .L793,r5
 4206 18b6 2519                 mov.l   r2,@(20,r9)
 4207 18b8 2619                 mov.l   r2,@(24,r9)
 4210 18ba 9C35                 add     r9,r5
 4211 18bc 0B41                 jsr     @r1
...
3329:./decompress.i ****              s->k0  = indexIntoF ( s->tPos, s->cftab ); s->tPos = (((UInt32)s->ll16[ s->tPos ]) | (
 4254 1900 53D1                 mov.l   .L792,r1
 4255 1902 FC7F                 add     #-4,r15		<- here
 4256 1904 9E95                 mov.w   .L793,r5
 4257 1906 9E54                 mov.l   @(56,r9),r4
 4258 1908 0B41                 jsr     @r1
 4259 190a 9C35                 add     r9,r5
 4260 190c 9B91                 mov.w   .L794,r1
...
3383:./decompress.i ****       default: { if (!(  ((Bool)0)  )) bz__AssertH__fail (   4001   ); } ;
 4971 1e00 2BD8                 mov.l   .L803,r8
 4972 1e02 5394                 mov.w   .L804,r4
 4973 1e04 0B48                 jsr     @r8
 4974 1e06 FC7F                 add     #-4,r15		<- here
3384:./decompress.i ****    }
3385:./decompress.i ****
3386:./decompress.i ****    { if (!(  ((Bool)0)  )) bz__AssertH__fail (   4002   ); } ;
 4977 1e08 5194                 mov.w   .L805,r4
 4978 1e0a 0B48                 jsr     @r8
 4979 1e0c 0900                 nop
 4980 1e0e 047F                 add     #4,r15		<- here
...


Toshi