MI can represent fallthrough to layout successor blocks, and our
post-isel representation uses that extensively.
We might as well use it too, to avoid translating and carrying along
unnecessary branches.
llvm-svn: 298459
A bool is represented by a single byte, which the ARM ABI requires to be either
0 or 1. So we cannot use G_ANYEXT when legalizing the type.
llvm-svn: 298439
This commit adds a parameter that lets us pass in the calling convention
of the call to CallLowering::lowerCall. This allows us to handle
situations where the calling convetion of the callee is different from
that of the caller.
Differential Revision: https://reviews.llvm.org/D31039
llvm-svn: 298254
Folding instructions when selecting can cause them to become dead.
Don't select these dead instructions (if they don't have other side
effects, and don't define physical registers).
Preserve existing tests by adding COPYs.
In some tests, the G_CONSTANT vregs never get constrained to a class:
the only use of the vreg was folded into another instruction, so the
G_CONSTANT, now dead, never gets selected.
llvm-svn: 298224
And remove some redundant bitcast tests.
Also split the test functions themselves: it makes it obvious to see
what's tested where and what isn't, it makes the tests much easier to
read and manually update, and, most importantly, it makes them almost
trivial to update using tooling. Yes, it's obnoxiously verbose, but
said tooling helps upgrade to better MIR syntax whenever available.
llvm-svn: 298222
Earlier stages of GlobalISel always use ConstantInt in G_CONSTANT so that's
what we should check for.
This fixes a crash introduced in r297782.
llvm-svn: 297968
Currently, we create a G_CONSTANT for every "synthetic" integer
constant operand (for instance, for the G_GEP offset).
Instead, share the G_CONSTANTs we might have created by going through
the ValueToVReg machinery.
When we're emitting synthetic constants, we do need to get Constants from
the context. One could argue that we shouldn't modify the context at
all (for instance, this means that we're going to use a tad more memory
if the constant wasn't used elsewhere), but constants are mostly
harmless. We currently do this for extractvalue and all.
For constant fcmp, this does mean we'll emit an extra COPY, which is not
necessarily more optimal than an extra materialized constant.
But that preserves the current intended design of uniqued G_CONSTANTs,
and the rematerialization problem exists elsewhere and should be
resolved with a single coherent solution.
llvm-svn: 297875
Now that we preserve the IR layout, we would end up with all the newly
synthesized switch comparison blocks at the end of the function.
Instead, use a hopefully more reasonable layout, with the comparison
blocks immediately following the switch comparison blocks.
llvm-svn: 297869
It makes the output function layout more predictable; the layout has
an effect on performance, we don't want it to be at the mercy of the
translator's visitation order and such.
The predictable output is also easier to digest.
getOrCreateBB isn't appropriately named anymore, as it never needs to
create anything. Rename it and extract the MBB creation logic out of it.
A couple tests were sensitive to the order. Update them.
llvm-svn: 297868
Summary:
<1 x Ty> is not a legal vector type in LLT, we shouldn’t build G_MERGE_VALUES
instruction for them.
Reviewers: qcolombet, aditya_nandakumar, dsanders, t.p.northover, ab, javed.absar
Reviewed By: qcolombet
Subscribers: dberris, rovka, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D30948
llvm-svn: 297792
Summary:
Adds a new kind of MachineOperand: MO_Placeholder.
This operand must not appear in the MIR and only exists as a way of
creating an 'uninitialized' operand until a matcher function overwrites it.
Depends on D30046, D29712
Reviewers: t.p.northover, ab, rovka, aditya_nandakumar, javed.absar, qcolombet
Reviewed By: qcolombet
Subscribers: dberris, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D30089
llvm-svn: 297782
The good reason to do this is that static allocas are pretty simple to handle
(especially at -O0) and avoiding tracking DBG_VALUEs throughout the pipeline
should give some kind of performance benefit.
The bad reason is that the debug pipeline is an unholy mess of implicit
contracts, where determining whether "DBG_VALUE %reg, imm" actually implies a
load or not involves the services of at least 3 soothsayers and the sacrifice
of at least one chicken. And it still gets it wrong if the variable is at SP
directly.
llvm-svn: 297410
We were calculating incorrect extract/insert offsets by trying to be too
tricksy with min/max. It's clearer to just split the logic up into "register
starts before this segment" vs "after".
llvm-svn: 297226
Some intrinsics take metadata parameters. These all need custom
handling of some form, and cannot possibly be lowered generically to
G_INTRINSIC calls with vreg operands.
Reject them, instead of hitting an assert later in getOrCreateVReg.
llvm-svn: 297209
When we translate a no-op (same type) bitcast, we try to be clever and
only emit a COPY if we already assigned a vreg to the defined value.
However, when we didn't, we tried to assign to a reference into the
ValToVReg DenseMap, even though the RHS of the assignment
(getOrCreateVReg) could potentially grow that DenseMap, invalidating the
reference.
Avoid that by getting the source vreg first.
I audited the rest of the translator; this is the only tricky case.
The test is quite unwieldy, as the problem is caused by the DenseMap
growing, which happens after the 47th mapped value.
llvm-svn: 297208
For vector operands, the `select` instruction supports both vector and
non-vector conditions. The MIR builder had an overly restrictive
assertion, that only accepted vector conditions for vector selects
(in effect implementing ISD::VSELECT).
Make it possible to express the full range of G_SELECTs.
llvm-svn: 297207
When computing the mapping for non-generic instructions, we skipped
%noreg operands, because we can't always reason about their banks.
Also skip them when applying the mapping. Otherwise, we could end
up with mappings that we can't apply.
While there, duplicate an assert to distinguish between the two
error conditions.
llvm-svn: 297201
When a dbg_value has a constant operand that isn't representable in MI,
there isn't much we can do. Use %noreg (0) for those situations.
This matches the SelectionDAG behavior.
llvm-svn: 297200
A bit more painful than G_INSERT because it was more widely used, but this
should simplify the handling of extract operations in most locations.
llvm-svn: 297100
Before, we were producing G_INSERT instructions that were actually closer to a
cast or even a COPY when both input and output sizes are the same. This doesn't
really make sense and means that everything interpreting a G_INSERT also has to
handle all these kinds of casts.
So now we detect these degenerate cases and emit real casts instead.
llvm-svn: 297051
Now that G_INSERT instructions can only insert one register, this code was
overly general. In another direction it didn't handle registers that crossed
split boundaries properly, which needed to be fixed.
llvm-svn: 297042
These are simplified variants of the current G_SEQUENCE and G_EXTRACT, which
assume the individual parts will be contiguous, homogeneous, and occupy the
entirity of the larger register. This makes reasoning about them much easer
since you only have to look at the first register being merged and the result
to know what the instruction is doing.
I intend to gradually replace all uses of the more complicated sequence/extract
with these (or single-element insert/extracts), and then remove the older
variants. For now we start with legalization.
llvm-svn: 296921
The CallingConv.td rules allocate 8 bytes for these kinds of arguments
on AAPCS targets, but we were only recording the smaller amount. The
difference is theoretical on AArch64 because we don't actually store
more than the smaller amount, but it's still much better to have these
two components in agreement.
Based on Diana Picus's ARM equivalent patch (where it matters a lot
more).
llvm-svn: 296754
Until now, we've had to use -global-isel to enable GISel. But using
that on other targets that don't support it will result in an abort, as we
can't build a full pipeline.
Additionally, we want to experiment with enabling GISel by default for
some targets: we can't just enable GISel by default, even among those
target that do have some support, because the level of support varies.
This first step adds an override for the target to explicitly define its
level of support. For AArch64, do that using
a new command-line option (I know..):
-aarch64-enable-global-isel-at-O=<N>
Where N is the opt-level below which GISel should be used.
Default that to -1, so that we still don't enable GISel anywhere.
We're not there yet!
While there, remove a couple LLVM_UNLIKELYs. Building the pipeline is
such a cold path that in practice that shouldn't matter at all.
llvm-svn: 296710
Iterating on the use-list we're modifying doesn't work: after the first
iteration, the use-list iterator will point to a MachineOperand
referencing the new register. This caused us to skip the other uses to
replace.
Instead, use MRI.replaceRegWith(), which accounts for this behavior.
llvm-svn: 296551
Ahmed Bougacha