5885 – wrong codegen for OPu32_d

Created attachment 948 [details] 
patch
struct Value {
 uint a, b;
}
double mul(Value val, double fac) {
 return val.a * fac;
}
int main() {
 auto a = mul(Value(10), 10.0); // seems to work as val.b == 0
 auto b = mul(Value(10, 20), 10.0); // loads the 20 in the fpu
 return a == b ? 0 : 1;
}
--
What happens is that the complete rdi register gets pushed and a 64 bit integer
is loaded from that address to the FPU. Maybe I'm missing something but loading
an 32 bit simplifies even the 32-bit code. See attached patch.

Created attachment 988 [details] 
new fix
The proposed patch was wrong. FILD m64int needs to be used as there are no unsigned->fpu load instructions. The new patch explicitly zeros the upper 4 bytes.

https://github.com/D-Programming-Language/dmd/commit/64a24b9276fd45c3040b5c726452a28add714cb7
https://github.com/D-Programming-Language/dmd/commit/bb40a40b6f804614ffc76ec79e10e7e1881b4c38