When an EBB argument value is used only as a return value, it still
needs to be given a register affinity. Otherwise it would appear as a
ghost value with no affinity.
Do the same to call arguments.
When an EBB argument value is used only as a return value, it still
needs to be given a register affinity. Otherwise it would appear as a
ghost value with no affinity.
Do the same to call arguments.
A function parameter in an incoming_arg stack slot should not be
coalesced into any virtual registers. We don't want to force the whole
virtual register to spill to the incoming_arg slot.
A function parameter in an incoming_arg stack slot should not be
coalesced into any virtual registers. We don't want to force the whole
virtual register to spill to the incoming_arg slot.
Function arguments that don't fit in registers are passed on the stack.
Create "incoming_arg" stack slots representing the stack arguments, and
assign them to the value arguments during spilling.
Function arguments that don't fit in registers are passed on the stack.
Create "incoming_arg" stack slots representing the stack arguments, and
assign them to the value arguments during spilling.
The offset is relative to the stack pointer in the calling function, so
it excludes the return address pushed by the call instruction itself on
Intel ISAs.
Change the ArgumentLoc::Stack offset to an i32, so it matches the stack
slot offsets.
The offset is relative to the stack pointer in the calling function, so
it excludes the return address pushed by the call instruction itself on
Intel ISAs.
Change the ArgumentLoc::Stack offset to an i32, so it matches the stack
slot offsets.
When coloring registers for a branch instruction, also make sure that
the values passed as EBB arguments are in the registers expected by the
EBB.
The first time a branch to an EBB is processed, assign the EBB arguments
to the registers where the branch arguments already reside so no
regmoves are needed.
When coloring registers for a branch instruction, also make sure that
the values passed as EBB arguments are in the registers expected by the
EBB.
The first time a branch to an EBB is processed, assign the EBB arguments
to the registers where the branch arguments already reside so no
regmoves are needed.
Ghost instructions don't generate code, but they can keep registers
alive. The coloring pass needs to process values killed by ghost
instructions so it knows when the registers are freed up.
Also track register pressure changes from ghost kills in the spiller.
Ghost instructions don't generate code, but they can keep registers
alive. The coloring pass needs to process values killed by ghost
instructions so it knows when the registers are freed up.
Also track register pressure changes from ghost kills in the spiller.
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.
