Displaying 1 result from an estimated 1 matches for "extract_lo".
2007 May 21
1
[LLVMdev] instruction writing two successive registers
...other operations.
this works fine. except 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....