This covers both hard and soft float.
Hard float is easy, since it's just Legal.
Soft float is more involved, because there are several different ways to
handle it based on the predicate: one and ueq need not only one, but two
libcalls to get a result. Furthermore, we have large differences between
the values returned by the AEABI and GNU functions.
AEABI functions return a nice 1 or 0 representing true and respectively
false. GNU functions generally return a value that needs to be compared
against 0 (e.g. for ogt, the value returned by the libcall is > 0 for
true). We could introduce redundant comparisons for AEABI as well, but
they don't seem easy to remove afterwards, so we do different processing
based on whether or not the result really needs to be compared against
something (and just truncate if it doesn't).
llvm-svn: 307243
We have to widen the operands to 32 bits and then we can either use
hardware division if it is available or lower to a libcall otherwise.
At the moment it is not enough to set the Legalizer action to
WidenScalar, since for libcalls it won't know what to do (it won't be
able to find what size to widen to, because it will find Libcall and not
Legal for 32 bits). To hack around this limitation, we request Custom
lowering, and as part of that we widen first and then we run another
legalizeInstrStep on the widened DIV.
llvm-svn: 301166
Start using the Subtarget to make decisions about what's legal. In particular,
we only mark floating point operations as legal if we have VFP2, which is
something we should've done from the very start.
llvm-svn: 295439
Diana Picus