A DomainValue is a bit like LiveIntervals' ValNo, but it also keeps track of execution domains.
Declared in <llvm/CodeGen/ExecutionDomainFix.h>
struct DomainValue;An open DomainValue represents a set of instructions that can still switch execution domain. Multiple registers may refer to the same open DomainValue - they will eventually be collapsed to the same execution domain.
A collapsed DomainValue represents a single register that has been forced into one of more execution domains. There is a separate collapsed DomainValue for each register, but it may contain multiple execution domains. A register value is initially created in a single execution domain, but if we were forced to pay the penalty of a domain crossing, we keep track of the fact that the register is now available in multiple domains.
| Name | Description |
|---|---|
DomainValue [constructor] | Default constructor |
addDomain | Mark domain as available. |
clear | Clear this DomainValue and point to next which has all its data. |
getCommonDomains | Return bitmask of domains that are available and in mask. |
getFirstDomain | First domain available. |
hasDomain | Is domain available? |
isCollapsed | A collapsed DomainValue has no instructions to twiddle - it simply keeps track of the domains where the registers are already available. |
setSingleDomain |
| Name | Description |
|---|---|
AvailableDomains | Bitmask of available domains. For an open DomainValue, it is the still possible domains for collapsing. For a collapsed DomainValue it is the domains where the register is available for free. |
Instrs | Twiddleable instructions using or defining these registers. |
Next | Pointer to the next DomainValue in a chain. When two DomainValues are merged, Victim.Next is set to point to Victor, so old DomainValue references can be updated by following the chain. |
Refs | Basic reference counting. |