Similar to SelectionDAG, this patch treats HwMode as an additional
predicate that needs to be satisfied for GIM_CheckFeatures.
The existing predicate passes around Record * that point to predicate
records. While HwMode expansion creates a string that needs to be
checked.
Each HwMode predicate string is uniqued by a new map that assigns
it an index. Each Rule stores the index, or -1 if HwMode doesn't
apply.
The HwMode indices each create a new Predicate feature bit and the
check string from the HwMode is used to set the feature bit.
GIM_CheckFeatures is emitted when the rule has Predicates or the HwModeIdx
is not -1.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D158660
PredicateBitset currently uses std::bitset, but std::bitset doesn't
have a constexpr constructor or any constexpr methods until C++23.
Each target that supports GlobalIsel has as an array of PredicateBitset
objects that currently use a global constructor.
SubtargetFeature used by the MC layer for feature bits, has its own
implementation of std::bitset that has constexpr constructor and methods
that provides all the capabilities that PredicateBitset needs.
This patch copies the implementation from SubtargetFeature, makes
it a template class, and puts it in ADT. I'll migrate SubtargetFeature
in a separate patch. Adapting all existing users to it being a template
was distracting from the goal of this patch.
This reduces the binary size of llc built with gcc 8.5.0 on my local
build by ~15k.
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D158576
Adds a new backend to power the GISel Combiners using the InstructionSelector's match tables.
This does not depend on any of the data structures created for the current combiner and is intended to replace it entirely.
See the RFC for more details: https://discourse.llvm.org/t/rfc-matchtable-based-globalisel-combiners/71457/6
Note: this would replace D141135.
Reviewed By: aemerson, arsenm
Differential Revision: https://reviews.llvm.org/D153757
Move all of the reusable logic out of `GlobalISelEmitter.cpp` into a `GlobalISelMatchTableExecutorEmitter` class so the future combiner backend can use it as well.
Depends on D153755
Reviewed By: aemerson
Differential Revision: https://reviews.llvm.org/D153756
