Displaying 1 result from an estimated 1 matches for "extract_hi".
2007 May 21
1
[LLVMdev] instruction writing two successive registers
...ept for the extra moves generated by the EXTRACT,
which can not be eliminated by coalescing, due to the differing register
classes.
here is a small example:
// Pn is a register pair
// 'a' and 'b' are regular registers
Pn = shuffle(x, y)
a = extract_lo(Pn) // which is a = Rn,
b = extract_hi(Pn) // which is b = Rn+1
here it would be nice to assign 'a' to the first subregister of Pn (Rn),
and b to the second (Rn+1).
instead of using the pair register class, i also thought about adding a
register constraint - something like TIED_TO_NEXT.
can anyone give me an advise how to ha...