Hello!

For the DF->SI testcases like this:

int test1(double a) {
        return sin(a);
}

current mainline gcc produces following code for -march=pentium4:
        ...
        fsin
        fstpl   (%esp)
        movsd   (%esp), %xmm0
        cvttsd2si       %xmm0, %eax
        ...
        ret

At least for pentium4 (and perhaps other !TARGET_K8 targets), xmm 
register could be avoided, as cvttsd2si can convert directly from memory 
to integer register. Attached patch introduces a couple of peephole2 
optimizers to get rid of extra movsd.
Unfortunatelly, combine pass can't be used in this case, because all 
necessary moves are generated in greg pass _after_ combine.

With attached patch, gcc generates following code:
test1:
        subl    $12, %esp
        fldl    16(%esp)
        fsin
        fstpl   (%esp)
        cvttsd2si       (%esp), %eax
        addl    $12, %esp
        ret

BTW: A small bug was fixed: *fix_trunchi_1 should have its split 
constraint defined.

Bootstrapped on i686-pc-linux-gnu, regtest in progres, c and c++.

2004-10-18  Uros Bizjak  <uros@kss-loka.si>

    * config/i386/i386.md (fix_truncsfdi_sse, fix_truncdfdi_sse,
    fix_truncsfsi_sse, fix_truncdfsi_sse): Add peephole2
    optimizers to avoid mem->sse_reg->reg in FP->int
    conversions for !TARGET_K8.
    (*fix_trunchi_1): Add "&& 1" as split constraint.

Uros.