We currently handle all aggregates by creating one large LLT, and letting the
legalizer deal with splitting them up. However using this approach means that
we can't support big endian code correctly.
This patch changes the way that the IRTranslator deals with aggregate values,
by splitting them up into their constituent element values. To do this, parts
of the translator need to be modified to deal with multiple VRegs for a single
Value.
A new Value to VReg mapper is introduced to help keep compile time under
control, currently there is no measurable impact on CTMark despite the extra
code being generated in some cases.
Patch is based on the original work of Tim Northover.
Differential Revision: https://reviews.llvm.org/D46018
llvm-svn: 332449
As Roman Tereshin pointed out in https://reviews.llvm.org/D45541, the
-global-isel option is redundant when -run-pass is given. -global-isel sets up
the GlobalISel passes in the pass manager but -run-pass skips that entirely and
configures it's own pipeline.
llvm-svn: 331603
Summary:
Currently only the memory size is supported but others can be added as
needed.
narrowScalar for G_LOAD and G_STORE now correctly update the
MachineMemOperand and will refuse to legalize atomics since those need more
careful expansions to maintain atomicity.
Reviewers: ab, aditya_nandakumar, bogner, rtereshin, aemerson, javed.absar
Reviewed By: aemerson
Subscribers: aemerson, rovka, kristof.beyls, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D45466
llvm-svn: 331071
Discussed here:
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120320.html
In preparation for adding support for named vregs we are changing the sigil for
physical registers in MIR to '$' from '%'. This will prevent name clashes of
named physical register with named vregs.
llvm-svn: 323922
Legal if we have hardware support for floating point, libcalls
otherwise.
Also add the necessary support for libcalls in the legalizer helper.
llvm-svn: 323726
Summary:
Apparently, we missed on constraining register classes of VReg-operands of all the instructions
built from a destination pattern but the root (top-level) one. The issue exposed itself
while selecting G_FPTOSI for armv7: the corresponding pattern generates VTOSIZS wrapped
into COPY_TO_REGCLASS, so top-level COPY_TO_REGCLASS gets properly constrained,
while nested VTOSIZS (or rather its destination virtual register to be exact) does not.
Fixing this by issuing GIR_ConstrainSelectedInstOperands for every nested GIR_BuildMI.
https://bugs.llvm.org/show_bug.cgi?id=35965
rdar://problem/36886530
Patch by Roman Tereshin
Reviewers: dsanders, qcolombet, rovka, bogner, aditya_nandakumar, volkan
Reviewed By: dsanders, qcolombet, rovka
Subscribers: aemerson, javed.absar, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D42565
llvm-svn: 323692
This is the groundwork for Armv8.2-A FP16 code generation .
Clang passes and returns _Float16 values as floats, together with the required
bitconverts and truncs etc. to implement correct AAPCS behaviour, see D42318.
We will implement half-precision argument passing/returning lowering in the ARM
backend soon, but for now this means that this:
_Float16 sub(_Float16 a, _Float16 b) {
return a + b;
}
gets lowered to this:
define float @sub(float %a.coerce, float %b.coerce) {
entry:
%0 = bitcast float %a.coerce to i32
%tmp.0.extract.trunc = trunc i32 %0 to i16
%1 = bitcast i16 %tmp.0.extract.trunc to half
<SNIP>
%add = fadd half %1, %3
<SNIP>
}
When FullFP16 is *not* supported, we don't make f16 a legal type, and we get
legalization for "free", i.e. nothing changes and everything works as before.
And also f16 argument passing/returning is handled.
When FullFP16 is supported, we do make f16 a legal type, and have 2 places that
we need to patch up: f16 argument passing and returning, which involves minor
tweaks to avoid unnecessary code generation for some bitcasts.
As a "demonstrator" that this works for the different FP16, FullFP16, softfp
modes, etc., I've added match rules to the VSUB instruction description showing
that we can codegen this instruction from IR, but more importantly, also to
some conversion instructions. These conversions were causing issue before in
the FP16 and FullFP16 cases.
I've also added match rules to the VLDRH and VSTRH desriptions, so that we can
actually compile the entire half-precision sub code example above. This showed
that these loads and stores had the wrong addressing mode specified: AddrMode5
instead of AddrMode5FP16, which turned out not be implemented at all, so that
has also been added.
This is the minimal patch that shows all the different moving parts. In patch
2/3 I will add some efficient lowering of bitcasts, and in 2/3 I will add the
remaining Armv8.2-A FP16 instruction descriptions.
Thanks to Sam Parker and Oliver Stannard for their help and reviews!
Differential Revision: https://reviews.llvm.org/D38315
llvm-svn: 323512
https://reviews.llvm.org/D42402
A lot of these copies are useless (copies b/w VRegs having the same
regclass) and should be cleaned up.
llvm-svn: 323291
It appears that we haven't been prioritizing rules that contain nested
instructions properly. InstructionOperandMatcher didn't override
isHigherPriorityThan so it never compared the instructions/operands/predicates
inside nested instructions.
Fixes PR35926. Thanks to Diana Picus for the bug report.
llvm-svn: 322754
Mark G_FPEXT and G_FPTRUNC as legal or libcall, depending on hardware
support, but only for conversions between float and double.
Also add the necessary boilerplate so that the LegalizerHelper can
introduce the required libcalls. This also works only for float and
double, but isn't too difficult to extend when the need arises.
llvm-svn: 322651
For hard float with VFP4, it is legal. Otherwise, we use libcalls.
This needs a bit of support in the LegalizerHelper for soft float
because we didn't handle G_FMA libcalls yet. The support is trivial, as
the only difference between G_FMA and other libcalls that we already
handle is that it has 3 input operands rather than just 2.
llvm-svn: 322366
For hard float, it is legal.
For soft float, we need to lower to 0 - x first, and then we can use the
libcall for G_FSUB. This is undoing some of the canonicalization
performed by the IRTranslator (which introduces G_FNEG when it sees a
0 - x). Ideally, that canonicalization would be performed by a
pre-legalizer pass that would allow targets to opt out of this behaviour
rather than dance around it in the legalizer.
llvm-svn: 322168
Planning to add support for named vregs. This puts is in a conundrum since
physregs are named as well. To rectify this we need to use a sigil other than
'%' for physregs in MIR. We've settled on using '$' for physregs but first we
must repurpose it from external symbols using it, which is what this commit is
all about. We think '&' will have familiar semantics for C/C++ users.
llvm-svn: 322146
Select G_PHI to PHI and manually constrain the result register. This is
very similar to how COPY is handled, so extract and reuse some of that
code.
llvm-svn: 321797
We used to handle G_CONSTANT with pointer type by forcing the type of
the result register to s32 and then letting TableGen handle it.
Unfortunately, setting the type only works for generic virtual
registers, that haven't yet been constrained to a register class (e.g.
those used only by a COPY later on). If the result register has already
been constrained as a use of a previously selected instruction, then
setting the type will assert.
It would be nice to be able to teach TableGen to select pointer
constants the same as integer constants, but since it's such an edge
case (at the moment the only pointer constant that we're generally
interested in is 0, and that is mostly used for comparisons and selects,
which are also not supported by TableGen) it's probably not worth the
effort right now. Instead, handle pointer constants with some trivial
handwritten code.
llvm-svn: 321793
Pointer constants are pretty rare, since we usually represent them as
integer constants and then cast to pointer. One notable exception is the
null pointer constant, which is represented directly as a G_CONSTANT 0
with pointer type. Mark it as legal and make sure it is selected like
any other integer constant.
llvm-svn: 321354
We get an assertion in RegBankSelect for code along the lines of
my_32_bit_int = my_64_bit_int, which tends to translate into a 64-bit
load, followed by a G_TRUNC, followed by a 32-bit store. This appears in
a couple of places in the test-suite.
At the moment, the legalizer doesn't distinguish between integer and
floating point scalars, so a 64-bit load will be marked as legal for
targets with VFP, and so will the rest of the sequence, leading to a
slightly bizarre G_TRUNC reaching RegBankSelect.
Since the current support for 64-bit integers is rather immature, this
patch works around the issue by explicitly handling this case in
RegBankSelect and InstructionSelect. In the future, we may want to
revisit this decision and make sure 64-bit integer loads are narrowed
before reaching RegBankSelect.
llvm-svn: 321165
This is due to PR26161 needing to be resolved before we can fix
big endian bugs like PR35359. The work to split aggregates into smaller LLTs
instead of using one large scalar will take some time, so in the mean time
we'll fall back to SDAG.
Some ARM BE tests xfailed for now as a result.
Differential Revision: https://reviews.llvm.org/D40789
llvm-svn: 320388
Test (some of) the patterns for selecting PKHBT and PKHTB. The others
are just very similar to the ones we're testing and there would be
little value in covering them as well.
llvm-svn: 320352
output
As part of the unification of the debug format and the MIR format,
always use `printReg` to print all kinds of registers.
Updated the tests using '_' instead of '%noreg' until we decide which
one we want to be the default one.
Differential Revision: https://reviews.llvm.org/D40421
llvm-svn: 319445
When lowering a G_BRCOND, we generate a TSTri of the condition against
1, which sets the flags, and then a Bcc which branches based on the
value of the flags.
Unfortunately, we were using the wrong condition code to check whether
we need to branch (EQ instead of NE), which caused all our branches to
do the opposite of what they were intended to do. This patch fixes the
issue by using the correct condition code.
llvm-svn: 319313
Summary:
From the bug report:
> The problem is that it fails when trying to compare -65536 (or 4294901760) to 0xFFFF,0000. This is because the
> constant in the instruction is sign extended to 64 bits (0xFFFF,FFFF,FFFF,0000) and then compared to the non
> extended 64 bit version expected by TableGen.
>
> In contrast, the DAGISelEmitter generates special code for AND immediates (OPC_CheckAndImm), which does not
> sign extend.
This patch doesn't introduce the special case for AND (and OR) immediates since the majority of it is related to handling known bits that have no effect on the result and GlobalISel doesn't detect known-bits at this time. Instead this patch just ensures that the immediate is extended consistently on both sides of the check.
Thanks to Diana Picus for the detailed bug report.
Reviewers: rovka
Reviewed By: rovka
Subscribers: kristof.beyls, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D40532
llvm-svn: 319252
TableGen already generates code for selecting a G_FDIV, so we only need
to add a test.
For the legalizer and reg bank select, we do the same thing as for the
other floating point binary operations: either mark as legal if we have
a FP unit or lower to a libcall, and map to the floating point
registers.
llvm-svn: 318915
TableGen already generates code for selecting a G_FMUL, so we only need
to add a test for that part.
For the legalizer and reg bank select, we do the same thing as the other
floating point binary operators: either mark as legal if we have a FP
unit or lower to a libcall, and map to the floating point registers.
llvm-svn: 318910
Add instruction selector test for RSBri, which is derived from
AsI1_rbin_irs, and make sure it doesn't get mistaken for SUBri, which is
derived from the very similar AsI1_bin_irs pattern.
llvm-svn: 318643
Remove some of the instruction selector tests for binary operators (and,
or, xor). These are all derived from the same kind of TableGen pattern,
AsI1_bin_irs, so there's no point in testing all of them.
llvm-svn: 318642
Alexander Ivchenko