[project @ 2001-12-14 15:26:14 by sewardj]
Get rid of multiple-result MachOps (MO_NatS_AddC, MO_NatS_SubC,
MO_NatS_MulC) which implement {add,sub,mul}IntC#. Supporting gunk
in the NCG disappears as a result.
Instead:
* {add,sub}IntC# are translated out during abstract C simplification,
turning into the xor-xor-invert-and-shift sequence previously defined
in PrimOps.h.
* mulIntC# is more difficult to get rid of portably. Instead we have
a new single-result PrimOp, mulIntMayOflo, with corresponding MachOp
MO_NatS_MulMayOflo. This tells you whether a W x W -> W signed
multiply might overflow, where W is the word size. When W=32, is
implemented by computing a 2W-long result. When W=64, we use the
previous approximation.
PrelNum.lhs' implementation of timesInteger changes slightly, to use
the new PrimOp.
16 files changed: