Ulrich Weigand 35dfd1b7df [SystemZ] Improve codegen for certain SADDO-immediate cases ...

When performing an add-with-overflow with an immediate in the
range -2G ... -4G, code currently loads the immediate into a
register, which generally takes two instructions.

In this particular case, it is preferable to load the negated
immediate into a register instead, which always only requires
one instruction, and then perform a subtract.

llvm-svn: 357597

2019-04-03 15:09:19 +00:00

7.9 KiB

Raw Blame History

View Raw