Insert a TSTri to set the flags and a Bcc to branch based on their
values. This is a bit inefficient in the (common) cases where the
condition for the branch comes from a compare right before the branch,
since we set the flags both as part of the compare lowering and as part
of the branch lowering. We're going to live with that until we settle on
a principled way to handle this kind of situation, which occurs with
other patterns as well (combines might be the way forward here).
llvm-svn: 308009
Constants are crucial for code size in the ARM Thumb-1 instruction
set. The 16 bit instruction size often does not offer enough space
for immediate arguments. This means that additional instructions are
frequently used to load constants into registers. Since constants are
hoisted, this can lead to significant register spillage if they are
used multiple times in a single function. This can be avoided by
rematerialization, i.e. recomputing a constant instead of reloading
it from the stack. This patch fixes the rematerialization of literal
pool loads in the ARM Thumb instruction set.
Patch by Philip Ginsbach
Differential Revision: https://reviews.llvm.org/D33936
llvm-svn: 308004
This boils down to not crashing in reg bank select due to the lack of
register operands on this instruction, and adding some tests. The
instruction selection is already covered by the TableGen'erated code.
llvm-svn: 307904
This patch tidies up and organises ARM.td
so that it is easier to understandand
and extend in the future.
Reviewed by: @hahn, @rovka
Differential Revision: https://reviews.llvm.org/D35248
llvm-svn: 307897
Summary:
Similar to X86, it should be safe to inline callees if their
target-features are a subset of the caller. As some subtarget features
provide different instructions depending on whether they are set or
unset (e.g. ThumbMode and ModeSoftFloat), we use a whitelist of
target-features describing hardware capabilities only.
Reviewers: kristof.beyls, rengolin, t.p.northover, SjoerdMeijer, peter.smith, silviu.baranga, efriedma
Reviewed By: SjoerdMeijer, efriedma
Subscribers: dschuff, efriedma, aemerson, sdardis, javed.absar, arichardson, eraman, llvm-commits
Differential Revision: https://reviews.llvm.org/D34697
llvm-svn: 307889
When we have a diamond ifcvt the fallthough block will have a branch at the end
of it that disappears when predicated, so discount it from the predication cost.
Differential Revision: https://reviews.llvm.org/D34952
llvm-svn: 307788
Refactor CmpHelper into something simpler. It was overkill to use
templates for this - instead, use a simple CmpConstants structure to
hold the opcodes and other constants that are different when selecting
int / float / double comparisons. Also, extract some of the helpers that
were in CmpHelper into ARMInstructionSelector and make use of some of
them when selecting other things than just compares.
llvm-svn: 307766
The issue is not if the value is pcrel. It is whether we have a
relocation or not.
If we have a relocation, the static linker will select the upper
bits. If we don't have a relocation, we have to do it.
llvm-svn: 307730
OpenCL 2.0 introduces the notion of memory scopes in atomic operations to
global and local memory. These scopes restrict how synchronization is
achieved, which can result in improved performance.
This change extends existing notion of synchronization scopes in LLVM to
support arbitrary scopes expressed as target-specific strings, in addition to
the already defined scopes (single thread, system).
The LLVM IR and MIR syntax for expressing synchronization scopes has changed
to use *syncscope("<scope>")*, where <scope> can be "singlethread" (this
replaces *singlethread* keyword), or a target-specific name. As before, if
the scope is not specified, it defaults to CrossThread/System scope.
Implementation details:
- Mapping from synchronization scope name/string to synchronization scope id
is stored in LLVM context;
- CrossThread/System and SingleThread scopes are pre-defined to efficiently
check for known scopes without comparing strings;
- Synchronization scope names are stored in SYNC_SCOPE_NAMES_BLOCK in
the bitcode.
Differential Revision: https://reviews.llvm.org/D21723
llvm-svn: 307722
For ELF, a movw+movt pair is handled as two separate relocations.
If an offset should be applied to the symbol address, this offset is
stored as an immediate in the instruction (as opposed to stored as an
offset in the relocation itself).
Even though the actual value stored in the movt immediate after linking
is the top half of the value, we need to store the unshifted offset
prior to linking. When the relocation is made during linking, the offset
gets added to the target symbol value, and the upper half of the value
is stored in the instruction.
This makes sure that movw+movt with offset symbols get properly
handled, in case the offset addition in the lower half should be
carried over to the upper half.
This makes the output from the additions to the test case match
the output from GNU binutils.
For COFF and MachO, the movw/movt relocations are handled as a pair,
and the overflow from the lower half gets carried over to the movt,
so they should keep the shifted offset just as before.
Differential Revision: https://reviews.llvm.org/D35242
llvm-svn: 307713
This change allows the pc to be used as a destination register for the
pseudo instruction LDR pc,=expression . The pseudo instruction must not be
transformed into a MOV, but it can use the Thumb2 LDR (literal) instruction
to a constant pool entry. See (A7.7.43 from ARMv7M ARM ARM).
Differential Revision: https://reviews.llvm.org/D34751
llvm-svn: 307640
We used to forget to erase the original instruction when replacing a
G_FCMP true/false. Fix this bug and make sure the tests check for it.
llvm-svn: 307639
r306334 fixed a bug in AArch64 dealing with wide interleaved accesses having
pointer types. The bug also exists in ARM, so this patch copies over the fix.
llvm-svn: 307409
We lower to a sequence consisting of:
- MOVi 0 into a register
- VCMPS to do the actual comparison and set the VFP flags
- FMSTAT to move the flags out of the VFP unit
- MOVCCi to either use the "zero register" that we have previously set
with the MOVi, or move 1 into the result register, based on the values
of the flags
As was the case with soft-float, for some predicates (one, ueq) we
actually need two comparisons instead of just one. When that happens, we
generate two VCMPS-FMSTAT-MOVCCi sequences and chain them by means of
using the result of the first MOVCCi as the "zero register" for the
second one. This is a bit overkill, since one comparison followed by
two non-flag-setting conditional moves should be enough. In any case,
the backend manages to CSE one of the comparisons away so it doesn't
matter much.
Note that unlike SelectionDAG and FastISel, we always use VCMPS, and not
VCMPES. This makes the code a lot simpler, and it also seems correct
since the LLVM Lang Ref defines simple true/false returns if the
operands are QNaN's. For SNaN's, even VCMPS throws an Invalid Operand
exception, so they won't be slipping through unnoticed.
Implementation-wise, this introduces a template so we can share the same
code that we use for handling integer comparisons, since the only
differences are in the details (exact opcodes to be used etc). Hopefully
this will be easy to extend to s64 G_FCMP.
llvm-svn: 307365
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 used to have a helper that replaced an instruction with a libcall.
That turns out to be too aggressive, since sometimes we need to replace
the instruction with at least two libcalls. Therefore, change our
existing helper to only create the libcall and leave the instruction
removal as a separate step. Also rename the helper accordingly.
llvm-svn: 307149
This implements suggesting other mnemonics when an invalid one is specified,
for example:
$ echo "adXd r1,r2,#3" | llvm-mc -triple arm
<stdin>:1:1: error: invalid instruction, did you mean: add, qadd?
adXd r1,r2,#3
^
The implementation is target agnostic, but as a first step I have added it only
to the ARM backend; so the ARM backend is a good example if someone wants to
enable this too for another target.
Differential Revision: https://reviews.llvm.org/D33128
llvm-svn: 307148
Summary:
Replace the matcher if-statements for each rule with a state-machine. This
significantly reduces compile time, memory allocations, and cumulative memory
allocation when compiling AArch64InstructionSelector.cpp.o after r303259 is
recommitted.
The following patches will expand on this further to fully fix the regressions.
Reviewers: rovka, ab, t.p.northover, qcolombet, aditya_nandakumar
Reviewed By: ab
Subscribers: vitalybuka, aemerson, javed.absar, igorb, llvm-commits, kristof.beyls
Differential Revision: https://reviews.llvm.org/D33758
llvm-svn: 307079
This enables us to ensure better LTO and code generation in the face of module linking.
Remove a report_fatal_error from the TargetMachine and replace it with an assert in ARMSubtarget - and remove the test that depended on the error. The assertion will still fire in the case that we were reporting before, but error reporting needs to be in front end tools if possible for options parsing.
llvm-svn: 306939
On big-endian machines the high and low parts of the value accessed by ldrexd
and strexd are swapped around. To account for this we swap inputs and outputs
in ISelLowering.
Patch by Bharathi Seshadri.
llvm-svn: 306865
In r301116, a custom lowering needed to be introduced to be able to
legalize 8 and 16-bit divisions on ARM targets without a division
instruction, since 2-step legalization (WidenScalar from 8 bit to 32
bit, then Libcall the 32-bit division) doesn't work.
This fixes this and makes this kind of multi-step legalization, where
first the size of the type needs to be changed and then some action is
needed that doesn't require changing the size of the type,
straighforward to specify.
Differential Revision: https://reviews.llvm.org/D32529
llvm-svn: 306806
Summary:
TBB and THH allow using a Thumb GPR or the PC as destination operand.
A few machine verifier failures where due to those instructions not
expecting PC as destination operand.
Add -verify-machineinstrs to test/CodeGen/ARM/jump-table-tbh.ll to add
test coverage even if expensive checks are disabled.
Reviewers: MatzeB, t.p.northover, jmolloy
Reviewed By: MatzeB
Subscribers: aemerson, javed.absar, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D34610
llvm-svn: 306654
The current heuristic in isProfitableToIfCvt assumes we have a branch predictor,
and so gives the wrong answer in some cases when we don't. This patch adds a
subtarget feature to indicate that a subtarget has no branch predictor, and
changes the heuristic in isProfitableToiIfCvt when it's present. This gives a
slight overall improvement in a set of embedded benchmarks on Cortex-M4 and
Cortex-M33.
Differential Revision: https://reviews.llvm.org/D34398
llvm-svn: 306547
The benchmarking summarized in
http://lists.llvm.org/pipermail/llvm-dev/2017-May/113525.html showed
this is beneficial for a wide range of cores.
As is to be expected, quite a few small adaptations are needed to the
regressions tests, as the difference in scheduling results in:
- Quite a few small instruction schedule differences.
- A few changes in register allocation decisions caused by different
instruction schedules.
- A few changes in IfConversion decisions, due to a difference in
instruction schedule and/or the estimated cost of a branch mispredict.
llvm-svn: 306514
* Mark as legal for (s32, i1, s32, s32)
* Map everything into GPRs
* Select to two instructions: a CMP of the condition against 0, to set
the flags, and a MOVCCr to select between the two inputs based on the
flags that we've just set
llvm-svn: 306382
Javed Absar