For some reason I never got around to adding these at the same time as
the signed versions. No idea why.
I'm not sure whether this SystemZII::BranchC* stuff is useful, or whether
it should just be replaced with an "is normal" flag. I'll leave that
for later though.
There are some boundary conditions that can be tweaked, such as preferring
unsigned comparisons for equality with [128, 256), and "<= 255" over "< 256",
but again I'll leave those for a separate patch.
llvm-svn: 190930
The main complication here is that TM and TMY (the memory forms) set
CC differently from the register forms. When the tested bits contain
some 0s and some 1s, the register forms set CC to 1 or 2 based on the
value the uppermost bit. The memory forms instead set CC to 1
regardless of the uppermost bit.
Until now, I've tried to make it so that a branch never tests for an
impossible CC value. E.g. NR only sets CC to 0 or 1, so branches on the
result will only test for 0 or 1. Originally I'd tried to do the same
thing for TM and TMY by using custom matching code in ISelDAGToDAG.
That ended up being very ugly though, and would have meant duplicating
some of the chain checks that the common isel code does.
I've therefore gone for the simpler alternative of adding an extra
operand to the TM DAG opcode to say whether a memory form would be OK.
This means that the inverse of a "TM;JE" is "TM;JNE" rather than the
more precise "TM;JNLE", just like the inverse of "TMLL;JE" is "TMLL;JNE".
I suppose that's arguably less confusing though...
llvm-svn: 190400
For now just handles simple comparisons of an ANDed value with zero.
The CC value provides enough information to do any comparison for a
2-bit mask, and some nonzero comparisons with more populated masks,
but that's all future work.
llvm-svn: 189469
For now this matches the equivalent of (neg (abs ...)), which did hit a few
times in projects/test-suite. We should probably also match cases where
absolute-like selects are used with reversed arguments.
llvm-svn: 188671
This first step just adds definitions for SLLK, SRLK and SRAK.
The next patch will actually make use of them during codegen.
insn-bad.s tests that some form of error is reported when using these
instructions on z10. More work is needed to get the "instruction requires:
distinct-ops" that we'd ideally like, so I've stubbed that part out for now.
I'll come back and make it mandatory once the necessary changes are in.
llvm-svn: 186680
RISBG has three 8-bit operands (I3, I4 and I5). I'd originally
restricted all three to 6 bits, since that's the only range we intended
to use at the time. However, the top bit of I4 acts as a "zero" flag for
RISBG, while the top bit of I3 acts as a "test" flag for RNSBG & co.
This patch therefore allows them to have the full 8-bit range.
I've left the fifth operand as a 6-bit value for now since the
upper 2 bits have no defined meaning.
llvm-svn: 186070
This is the first use of D(L,B) addressing, which required a fair bit
of surgery. For that reason, the patch just adds the instruction
definition and the associated assembler and disassembler support.
A later patch will actually make use of it for codegen.
llvm-svn: 185433
This patch adds support for the CRJ and CGRJ instructions. Support for
the immediate forms will be a separate patch.
The architecture has a large number of comparison instructions. I think
it's generally better to concentrate on using the "best" comparison
instruction first and foremost, then only use something like CRJ if
CR really was the natual choice of comparison instruction. The patch
therefore opportunistically converts separate CR and BRC instructions
into a single CRJ while emitting instructions in ISelLowering.
llvm-svn: 182764
Richard Sandiford