Software pipelining

[raya <raya@xxxxxxxxxxxxxxxxxxxxx>]

Hello,
I do not understand the code produced by PRO64:
For the following  C program:

int a[100];
int b[100];
main()
{
  int i;
  for (i =0;i<100;i++)
    {
      a[i] = b[i] + 5;
    }
}


Compiling with -O2 produced the following pipelined loop:
 {       .mii
 (p19) st4 [r3]=r35,4           // [3*II+0]  id:12 a+0x0
 (p18) adds r34=5,r37           // [2*II+0]
 (p18) nop.i 0                  // [2*II+0]
 }; {       .mfb
 (p16) ld4 r35=[r2],4           // [0*II+0]  id:11 b+0x0
 (p16) nop.f 0                  // [0*II+0]
       br.ctop.dptk.few .Lt_0_4 ;; // [3*II+0]
 };


Is this a  legal code? there is a store from r35 and load to r35 within
the same instruction group.

(The full assembly code, as well as the C source are attached).
--
Raya Leviathan
Tel. 972-8-9344208 (office)
Tel. 972-3-6358481 (home)
Email: raya@xxxxxxxxxxxxxxxxxxxxx

simpleO2.s
Description: application/unknown-content-type-s_auto_file

simple.c
Description: application/unknown-content-type-c_auto_file