xla::anonymous_namespace{copy_insertion.cc} Namespace Reference

Functions
Status	AddCopiesForWhile (const HloAliasAnalysis &alias_analysis, HloInstruction *xla_while)
Status	AddCopiesForConditional (const HloAliasAnalysis &alias_analysis, HloInstruction *conditional)
Status	AddCopiesToResolveInterference (HloModule *module)

Function Documentation

AddCopiesForConditional()

Status xla::anonymous_namespace{copy_insertion.cc}::AddCopiesForConditional	(	const HloAliasAnalysis &	alias_analysis,
		HloInstruction *	conditional
	)

Google docs:

We add copies for all the indices of the true and false computaiton roots, in order to resolve interference. We later rely on the CopyRemover to drop the unnecessary ones.

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AddCopiesForWhile()

Status xla::anonymous_namespace{copy_insertion.cc}::AddCopiesForWhile	(	const HloAliasAnalysis &	alias_analysis,
		HloInstruction *	xla_while
	)

Google docs in short:

Add kCopy instructions around the given kWhile instruction to eliminate any possible live range interference of HLO values assuming a dependency-based ordering (HloDependencyOrdering). Copies are added conservatively. There likely are copies which are not strictly necessary, but there are removed later in the pass via CopyRemover.

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AddCopiesToResolveInterference()

Status xla::anonymous_namespace{copy_insertion.cc}::AddCopiesToResolveInterference

(

HloModule *

module

)

Google docs:

Add kCopy instructions to the given module to guarantee there is no live-range interference. Generally interference can only occur around kWhile instructions which have update-in-place semantics.

For all the kWhile instruction, call AddCopiesForWhile()

For all the kConditional instruction, call AddCopiesForConditional()

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