TableGen would pick the largest RC for constraining the operands, which
could potentially be an unallocatable RC. This patch removes selection
of unallocatable RCs.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D93945
This was emitting the raw value for the reg class ID with a comment
for the actual class name. Switch to emitting the qualified enum name
instead, which obviates the need for the comment and also helps keep
the lit tests on the emitter output more stable.
This previously only handled EXTRACT_SUBREGs from leafs, such as
operands directly in the original output. Handle extracting from a
result instruction.
This was only using the correct register constraints if this was the
final result instruction. If the extract was a sub instruction of the
result, it would attempt to use GIR_ConstrainSelectedInstOperands on a
COPY, which won't work. Move the handling to
createAndImportSubInstructionRenderer so it works correctly.
I don't fully understand why runOnPattern and
createAndImportSubInstructionRenderer both need to handle these
special cases, and constrain them with slightly different methods. If
I remove the runOnPattern handling, it does break the constraint when
the final result instruction is EXTRACT_SUBREG.
llvm-svn: 371150
Reuse the logic for INSERT_SUBREG to also import SUBREG_TO_REG patterns.
- Split `inferSuperRegisterClass` into two functions, one which tries to use
an existing TreePatternNode (`inferSuperRegisterClassForNode`), and one that
doesn't. SUBREG_TO_REG doesn't have a node to leverage, which is the cause
for the split.
- Rename GlobalISelEmitterInsertSubreg.td to GlobalISelEmitterSubreg.td and
update it.
- Update impacted tests in the AArch64 and X86 backends.
This is kind of a hit/miss for code size improvements/regressions. E.g. in
add-ext.ll, we now get some identity copies. This isn't really anything the
importer can handle, since it's caused by a later pass introducing the copy for
the sake of correctness.
Differential Revision: https://reviews.llvm.org/D66769
llvm-svn: 370254
I thought `llvm::sort` was stable for some reason but it's not.
Use `llvm::stable_sort` in `CodeGenTarget::getSuperRegForSubReg`.
Original patch: https://reviews.llvm.org/D66498
llvm-svn: 370084
When EXPENSIVE_CHECKS are enabled, GlobalISelEmitterSubreg.td doesn't get
stable output.
Reverting while I debug it.
See: https://reviews.llvm.org/D66498
llvm-svn: 370080
This teaches the importer to handle INSERT_SUBREG instructions.
We were missing patterns involving INSERT_SUBREG in AArch64. It appears in
AArch64InstrInfo.td 107 times, and 14 times in AArch64InstrFormats.td.
To meaningfully import it, the GlobalISelEmitter needs to know how to infer a
super register class for a given register class.
This patch introduces the following:
- `getSuperRegForSubReg`, a function which finds the largest register class
which supports a value type and subregister index
- `inferSuperRegisterClass`, a function which finds the appropriate super
register class for an INSERT_SUBREG'
- `inferRegClassFromPattern`, a function which allows for some trivial
lookthrough into instructions
- `getRegClassFromLeaf`, a helper function which returns the register class for
a leaf `TreePatternNode`
- Support for subregister index operands in `importExplicitUseRenderer`
It also
- Updates tests in each backend which are impacted by the change
- Adds GlobalISelEmitterSubreg.td to test that we import and skip the expected
patterns
As a result of this patch, INSERT_SUBREG patterns in X86 may use the
LOW32_ADDR_ACCESS_RBP register class instead of GR32. This is correct, since the
register class contains the same registers as GR32 (except with the addition of
RBP). So, this also teaches X86 to handle that register class. This is in line
with X86ISelLowering, which treats this as a GR class.
Differential Revision: https://reviews.llvm.org/D66498
llvm-svn: 369973
Gabriel Hjort Åkerlund