The z13 vector facility includes some instructions that operate only on the
high f64 in a v2f64, effectively extending the FP register set from 16
to 32 registers. It's still better to use the old instructions if the
operands happen to fit though, since the older instructions have a shorter
encoding.
Based on a patch by Richard Sandiford.
llvm-svn: 236524
At the moment, all subregs defined by the SystemZ target can be modified
independently of the wider register. E.g. writing to a GR32 does not
change the upper 32 bits of the GR64. Writing to an FP32 does not change
the lower 32 bits of the FP64.
Hoewver, the upcoming support for the vector extension redefines FP64 as
one half of a V128. Floating-point operations leave the other half of
a V128 in an unpredictable state, so it's no longer the case that writing
to an FP32 leaves the bits of the underlying register (the V128) alone.
I'd prefer to have separate subreg_ names for this situation, so that
it's obvious at a glance whether we're talking about a subreg that leaves
the other parts of the register alone.
No behavioral change intended.
Patch originally by Richard Sandiford.
llvm-svn: 236433
...instead of a separate Requires for each one. This style was already
used in some places and seems more compact.
No behavioral change intended.
llvm-svn: 204452
Use subreg_hNN and subreg_lNN for the high and low NN bits of a register.
List the low registers first, so that subreg_l32 also means the low 32
bits of a 128-bit register.
Floats are stored in the upper 32 bits of a 64-bit register, so they
should use subreg_h32 rather than subreg_l32.
No behavioral change intended.
llvm-svn: 191659
The architecture has many comparison instructions, including some that
extend one of the operands. The signed comparison instructions use sign
extensions and the unsigned comparison instructions use zero extensions.
In cases where we had a free choice between signed or unsigned comparisons,
we were trying to decide at lowering time which would best fit the available
instructions, taking things like extension type into account. The code
to do that was getting increasingly hairy and was also making some bad
decisions. E.g. when comparing the result of two LLCs, it is better to use
CR rather than CLR, since CR can be fused with a branch while CLR can't.
This patch removes the lowering code and instead adds an operand to
integer comparisons to say whether signed comparison is required,
whether unsigned comparison is required, or whether either is OK.
We can then leave the choice of instruction up to the normal isel code.
llvm-svn: 190138
Lengths up to a certain threshold (currently 6 * 256) use a series of MVCs.
Lengths above that threshold use a loop to handle X*256 bytes followed
by a single MVC to handle the excess (if any). This loop will also be
needed in future when support for variable lengths is added.
Because the same tablegen classes are used to define MVC and CLC,
the patch also has the side-effect of defining a pseudo loop instruction
for CLC. That instruction isn't used yet (and wouldn't be handled correctly
if it were). I'm planning to use it soon though.
llvm-svn: 189331
This follows the same lines as the integer code. In the end it seemed
easier to have a second 4-bit mask in TSFlags to specify the compare-like
CC values. That eats one more TSFlags bit than adding a CCHasUnordered
would have done, but it feels more concise.
llvm-svn: 187883
Look for patterns of the form (store (load ...), ...) in which the two
locations are known not to partially overlap. (Identical locations are OK.)
These sequences are better implemented by MVC unless either the load or
the store could use RELATIVE LONG instructions.
The testcase showed that we weren't using LHRL and LGHRL for extload16,
only sextloadi16. The patch fixes that too.
llvm-svn: 185919
Add a mapping from register-based <INSN>R instructions to the corresponding
memory-based <INSN>. Use it to cut down on the number of spill loads.
Some instructions extend their operands from smaller fields, so this
required a new TSFlags field to say how big the unextended operand is.
This optimisation doesn't trigger for C(G)R and CL(G)R because in practice
we always combine those instructions with a branch. Adding a test for every
other case probably seems excessive, but it did catch a missed optimisation
for DSGF (fixed in r185435).
llvm-svn: 185529
Add pseudo conditional store instructions, so that we use:
branch foo:
store
foo:
instead of:
load
branch foo:
move
foo:
store
z196 has real 32-bit and 64-bit conditional stores, but we don't use
any z196 instructions yet.
llvm-svn: 185065
Addresses a review comment from Ulrich Weigand. No functional change intended.
I'm not sure whether the old TODO that this patch touches still holds,
but that's something we'd get to when adding a targetted scheduling
description.
llvm-svn: 182474
The SystemZ port currently relies on the order of the instruction operands
matching the order of the instruction field lists. This isn't desirable
for disassembly, where the two are matched only by name. E.g. the R1 and R2
fields of an RR instruction should have corresponding R1 and R2 operands.
The main complication is that addresses are compound operands,
and as far as I know there is no mechanism to allow individual
suboperands to be selected by name in "let Inst{...} = ..." assignments.
Luckily it doesn't really matter though. The SystemZ instruction
encoding groups all address fields together in a predictable order,
so it's just as valid to see the entire compound address operand as
a single field. That's the approach taken in this patch.
Matching by name in turn means that the operands to COPY SIGN and
CONVERT TO FIXED instructions can be given in natural order.
(It was easier to do this at the same time as the rename,
since otherwise the intermediate step was too confusing.)
No functional change intended.
llvm-svn: 181769
This adds the actual lib/Target/SystemZ target files necessary to
implement the SystemZ target. Note that at this point, the target
cannot yet be built since the configure bits are missing. Those
will be provided shortly by a follow-on patch.
This version of the patch incorporates feedback from reviews by
Chris Lattner and Anton Korobeynikov. Thanks to all reviewers!
Patch by Richard Sandiford.
llvm-svn: 181203
bunch of associated comments, because it doesn't have anything to do
with DAGs or scheduling. This is another step in decoupling MachineInstr
emitting from scheduling.
llvm-svn: 85517
eliminating a use of MVT::Flag, this is needed for an upcoming CodeGen
change.
This unfortunately requires SystemZ to switch to the list-burr
scheduler, in order to handle the physreg defs properly, however
that's what LLVM has available at this time.
llvm-svn: 85357
Ulrich Weigand