Re: floating-point abuse in 2.1.113

[Albert D. Cahalan]

>>>> How can that be a problem? Shouldn't the multiplication and cast
>>>> be evaluated at compile time, leaving only an int?

> main()
> {
>    float foo;
> 
>    foo = 1.0 * 1.0 * 1.0;
>    printf("%f\n", foo);
> 
> }

That's not the same thing at all though. The kernel code
was more like this:

main(){
  int foo;
  foo = (int) 1.0 * 1.0 * 1.0;
  printf("%d\n", foo);
}

It makes no sense to leave the floating point in the object file.
All I can figure is something related to IEEE rounding, in which
case there ought to be compiler switch to eliminate such concern.

Here is the above with gcc on the Alpha. I don't see any floating
point, do you?

        .verstamp 3 11
        .set noreorder
        .set volatile
        .set noat
        .file   1 "flt.c"
gcc2_compiled.:
__gnu_compiled_c:
.rdata
        .quad 0
        .align 3
$C32:
        .ascii "%d\12\0"
.text
        .align 3
        .globl main
        .ent main
main:
        ldgp $29,0($27)
main..ng:
        lda $30,-32($30)
        .frame $15,32,$26,0
        stq $26,0($30)
        stq $15,8($30)
        .mask 0x4008000,-32
        bis $30,$30,$15
        .prologue 1
        bis $31,1,$1
        stl $1,16($15)
        ldl $1,16($15)
        lda $16,$C32
        bis $1,$1,$17
        jsr $26,printf
        ldgp $29,0($26)
$33:
        bis $15,$15,$30
        ldq $26,0($30)
        ldq $15,8($30)
        addq $30,32,$30
        ret $31,($26),1
        .end main

-------- here is i386 code, same thing ------------

        .file   "flt.c"
        .version        "01.01"
gcc2_compiled.:
.section        .rodata
.LC0:
        .string "%d\n"
.text
        .align 4
.globl main
        .type    main,@function
main:
        pushl %ebp
        movl %esp,%ebp
        subl $4,%esp
        movl $1,-4(%ebp)
        movl -4(%ebp),%eax
        pushl %eax
        pushl $.LC0
        call printf
        addl $8,%esp
.L1:
        leave
        ret