When the spiller decides to spill a value, bring along all of the values
in its virtual register. This ensures that we won't have problems with
computing register pressure around EBB arguments. They will always be
register-to-register or stack-to-stack with related values using the
same stack slot.
This also means that the reloading pass won't have to deal with spilled
EBB arguments.
When the spiller decides to spill a value, bring along all of the values
in its virtual register. This ensures that we won't have problems with
computing register pressure around EBB arguments. They will always be
register-to-register or stack-to-stack with related values using the
same stack slot.
This also means that the reloading pass won't have to deal with spilled
EBB arguments.
* Convert TypeSet fields to sets; Add BitSet<T> type to rust; Encode ValueTypeSets using BitSet; (still need mypy cleanup)
* nits
* cleanup nits
* forgot mypy type annotations
* rustfmt fixes
* Round 1 comments: filer b2, b4; doc comments in python; move bitset in its own toplevel module; Use Into<u32>
* fixes
* Revert comment to appease rustfmt
* Convert TypeSet fields to sets; Add BitSet<T> type to rust; Encode ValueTypeSets using BitSet; (still need mypy cleanup)
* nits
* cleanup nits
* forgot mypy type annotations
* rustfmt fixes
* Round 1 comments: filer b2, b4; doc comments in python; move bitset in its own toplevel module; Use Into<u32>
* fixes
* Revert comment to appease rustfmt
Coalescing means creating virtual registers and transforming the code
into conventional SSA form. This means that every value used as a branch
argument will belong to the same virtual register as the corresponding
EBB argument value.
Conventional SSA form makes it easy to avoid memory-memory copies when
spilling values, and the virtual registers can be used as hints when
picking registers too. This reduces the number of register moves needed
for EBB arguments.
Coalescing means creating virtual registers and transforming the code
into conventional SSA form. This means that every value used as a branch
argument will belong to the same virtual register as the corresponding
EBB argument value.
Conventional SSA form makes it easy to avoid memory-memory copies when
spilling values, and the virtual registers can be used as hints when
picking registers too. This reduces the number of register moves needed
for EBB arguments.
Add a VirtRegs collection which tracks virtual registers.
A virtual register is a set of related SSA values whose live ranges
don't interfere. It is advantageous to use the same register or spill
slot for al the values in a virtual register. It reduces copies for EBB
arguments.
Add a VirtRegs collection which tracks virtual registers.
A virtual register is a set of related SSA values whose live ranges
don't interfere. It is advantageous to use the same register or spill
slot for al the values in a virtual register. It reduces copies for EBB
arguments.
Ghost instructions don't have an encoding, and don't appear in the
output. The values they define do not need to be assigned to registers,
so they can be skipped.
Ghost instructions don't have an encoding, and don't appear in the
output. The values they define do not need to be assigned to registers,
so they can be skipped.
The overlaps_def() method tests if a definition would conflict with the
live range.
The reaches_use() method tests if a live range is live at an
instruction.
The overlaps_def() method tests if a definition would conflict with the
live range.
The reaches_use() method tests if a live range is live at an
instruction.
* Clarify that extended basic blocks are abbreviated as EBB.
* Fix typo.
* Fix a typo.
* Fix typos.
* Use the same phrase to indicate scalar-only as other places in the doc.
* Mention that `band_imm` and friends are scalar-only.
And mention that they're equivalent to their respective
non-immediate-form counterparts.
* Clarify that extended basic blocks are abbreviated as EBB.
* Fix typo.
* Fix a typo.
* Fix typos.
* Use the same phrase to indicate scalar-only as other places in the doc.
* Mention that `band_imm` and friends are scalar-only.
And mention that they're equivalent to their respective
non-immediate-form counterparts.
The EntityRef trait is used by more than just the EntityMap now, so it
should live in its own module.
Also move the entity_impl! macro into the new module so it can be used
for defining new entity references anywhere.
The EntityRef trait is used by more than just the EntityMap now, so it
should live in its own module.
Also move the entity_impl! macro into the new module so it can be used
for defining new entity references anywhere.
* Replace a single-character string literal with a character literal.
* Use is_some() instead of comparing with Some(_).
* Add code-quotes around type names in comments.
* Use !...is_empty() instead of len() != 0.
* Tidy up redundant returns.
* Remove redundant .clone() calls.
* Remove unnecessary explicit lifetime parameters.
* Tidy up unnecessary '&'s.
* Add parens to make operator precedence explicit.
* Use debug_assert_eq instead of debug_assert with ==.
* Replace a &Vec argument with a &[...].
* Replace `a = a op b` with `a op= b`.
* Avoid unnecessary closures.
* Avoid .iter() and .iter_mut() for iterating over containers.
* Remove unneeded qualification.
* Replace a single-character string literal with a character literal.
* Use is_some() instead of comparing with Some(_).
* Add code-quotes around type names in comments.
* Use !...is_empty() instead of len() != 0.
* Tidy up redundant returns.
* Remove redundant .clone() calls.
* Remove unnecessary explicit lifetime parameters.
* Tidy up unnecessary '&'s.
* Add parens to make operator precedence explicit.
* Use debug_assert_eq instead of debug_assert with ==.
* Replace a &Vec argument with a &[...].
* Replace `a = a op b` with `a op= b`.
* Avoid unnecessary closures.
* Avoid .iter() and .iter_mut() for iterating over containers.
* Remove unneeded qualification.
* Implement an iterator over encodings
* Implement TargetIsa::legal_encodings
* Exclude non-boolean settings of isa flags bytes
* Address flake8 long line error
* Implement an iterator over encodings
* Implement TargetIsa::legal_encodings
* Exclude non-boolean settings of isa flags bytes
* Address flake8 long line error
As soon as a value is spilled, also assign it to a spill slot.
For now, create a new spill slot for each spilled value. In the future,
values will be sharing spill slots of they are phi-related.
As soon as a value is spilled, also assign it to a spill slot.
For now, create a new spill slot for each spilled value. In the future,
values will be sharing spill slots of they are phi-related.
Use a new StackSlots struct to keep track of a function's stack slots
instead of just an entity map. This let's us build more internal data
structures for tracking the stack slots if necessary.
Start by adding a make_spill_slot() function that will be used by the
register allocator.
Use a new StackSlots struct to keep track of a function's stack slots
instead of just an entity map. This let's us build more internal data
structures for tracking the stack slots if necessary.
Start by adding a make_spill_slot() function that will be used by the
register allocator.
Add a StackSlotKind enumeration to help keep track of the different
kinds of stack slots supported:
- Incoming and outgoing function arguments on the stack.
- Spill slots and locals.
Change the text format syntax for declaring a stack slot to use a kind
keyword rather than just 'stack_slot'.
Add a StackSlotKind enumeration to help keep track of the different
kinds of stack slots supported:
- Incoming and outgoing function arguments on the stack.
- Spill slots and locals.
Change the text format syntax for declaring a stack slot to use a kind
keyword rather than just 'stack_slot'.
An instruction may have fixed operand constraints that make it
impossibly to use a single register value to satisfy two at a time.
Detect when the same value is used for multiple fixed register operands
and insert copies during the spilling pass.
An instruction may have fixed operand constraints that make it
impossibly to use a single register value to satisfy two at a time.
Detect when the same value is used for multiple fixed register operands
and insert copies during the spilling pass.
Even if an argument is already in the correct register, make sure that
we detect conflicts by registering the no-op move. This also means that
the ABI argument register won't be turned into a variable for the
solver.
Even if an argument is already in the correct register, make sure that
we detect conflicts by registering the no-op move. This also means that
the ABI argument register won't be turned into a variable for the
solver.
