Implemented AreEquivalentConstants method to check equivalency of
constants, changing IsApplicable method of
TransformationRecordSynonymousConstants to allow recording equivalence
of composite constants; added some tests to check this.
Tests with arrays and matrices still need to be added.
Fixes#3533.
Add TransformationAddRelaxedDecoration, which adds the RelaxedPrecision decoration to ids of numeric instructions (those yielding 32-bit ints or floats) in dead blocks.
Fixes#3502
In this PR, the classes that represent the adjust branch weights
transformation and fuzzer pass were implemented. This transformation
adjusts the branch weights of a OpBranchConditional instruction.
The outliner would outline regions ending with a loop header, making
the block containing the call to the outlined function serve as the
loop header. This, however, is incorrect in general, since the whole
outlined function -- rather than just the exit block for the region --
would end up getting called every time the loop would iterate.
This change restricts the outliner so that the last block in a region
cannot be a loop header.
It has been resolved that statically out-of-bounds accesses are not
invalid in SPIR-V (they lead to undefind behaviour at runtime but
should not cause a module to be rejected during validation). This
change tolerates such accesses in donated code, clamping them in-bound
as part of making a function live-safe.
The Sample argument of OpImageTexelPointer is sometimes required to be
a zero constant. It thus cannot be replaced with a synonym in
general. This change avoids replacing this argument with a synonym.
The fact manager maintains an equivalence relation on data descriptors
that tracks when one data descriptor could be used in place of
another. An algorithm to compute the closure of such facts allows
deducing new synonym facts from existing facts. E.g., for two 2D
vectors u and v it is known that u.x is synonymous with v.x and u.y is
synonymous with v.y, it can be deduced that u and v are synonymous.
The closure computation algorithm is very expensive if we get large
equivalence relations.
This change addresses this in three ways:
- The size of equivalence relations is reduced by limiting the extent
to which the components of a composite are recursively noted as
being equivalent, so that when we have large synonymous arrays we do
not record all array elements as being pairwise equivalent.
- When computing the closure of facts, equivalence classes above a
certain size are simply skipped (which can lead to missed facts)
- The closure computation is performed less frequently - it is invoked
explicitly before fuzzer passes that will benefit from data synonym
facts. A new transformation is used to control its invocation, so
that fuzzing and replaying do not get out of sync.
The change also tidies up the order in which some getters are declared
in FuzzerContext.
Adds an extra condition on when a region can be outlined to avoid the
case where a region ends with a loop head but such that the loop's
continue target is in the region. (Outlining such a region would mean
that the loop merge is in the original function and the continue target
in the outlined function.)
The function outliner uses a struct to return ids that a region
generates and that are used outside that region. If these ids have
pointer type this would result in a struct with pointer members, which
leads to illegal loading from non-logical pointers if logical
addressing is used. This change bans that outlining possibility.
Provides support for runtime arrays in the code that traverses
composite types when checking applicability of transformations that
replace ids with synonyms.
Demotes the image storage class to Private during donation. Also
fixes an issue where instructions that depended on non-donated global
values would not be handled properly.
The SPIR-V data rules say that all uses of an OpSampledImage
instruction must be in the same block as the instruction, and highly
restrict those instructions that can consume the result id of an
OpSampledImage.
This adapts the transformations that split blocks and create synonyms
to avoid separating an OpSampledImage use from its definition, and to
avoid synonym-creation instructions such as OpCopyObject consuming an
OpSampledImage result id.
The management of equation facts suffered from two problems:
(1) The processing of an equation fact required the data descriptors
used in the equation to be in canonical form. However, during
fact processing it can be deduced that certain data descriptors
are equivalent, causing their equivalence classes to be merged,
and that could cause previously canonical data descriptors to no
longer be canonical.
(2) Related to this, if id equations were known about a canonical data
descriptor dd1, and other id equations known about a different
canonical data descriptor dd2, the equation facts about these data
descriptors were not being merged in the event that dd1 and dd2
were deduced to be equivalent.
This changes solves (1) by not requiring equation facts to be in
canonical form while processing them, but instead always checking
whether (not necessary canonical) data descriptors are equivalent when
looking for corollaries of equation facts, rather than comparing them
using ==.
Problem (2) is solved by adding logic to merge sets of equations when
data descriptors are made equivalent.
In addition, the change also requires elements to be registered in an
equivalence relation before they can be made equivalent, rather than
being added (if not already present) at the point of being made
equivalent.
This change increases the extent to which arbitrary SPIR-V can be used
by the fuzzer pass that donates modules. It handles the case where
various ingredients (such as types, variables and particular
instructions) cannot be donated by omitting them, and then either
omitting their dependencies or replacing their dependencies with
alternative instructions.
The change pays particular attention to allowing code that manipulates
image types to be handled (by skipping anything image-specific).
(1) Runtime arrays are turned into fixed-size arrays, by turning
OpTypeRuntimeArray into OpTypeArray and uses of OpArrayLength into
uses of the constant used for the length of the fixed-size array.
(2) Atomic instructions are not donated, and uses of their results are
replaced with uses of constants of the result type.
