* spirv-val: Allow the ViewportIndex and Layer built-ins when their corresponding SPIR-V 1.5 capabilities are present
* Added tests for OpCapability ShaderViewportIndex and OpCapability ShaderLayer
For some cases, we have DebugDecl invisible to a value assignment, but
the value assignment information is important i.e., debugger cannot inspect
the variable without the information. For example, a parameter of an inlined
function must have its value assignment i.e., argument passing out of its
function scope. If we simply remove DebugDecl because it is invisible to the
argument passing, we cannot inspec the variable.
This PR
- Adds DebugValue for DebugDecl invisible to a value assignment. We use
the value of the variable in the basic block that contains DebugDecl, which is
found by ssa-rewrite. If the value instruction does not dominate DebugDecl,
we use the value of the variable in the immediate dominator of the basic block.
- Checks the visibility of DebugDecl for Phi value assignment based on the
all value operands of the Phi. Since Phi just references multiple values from
multiple basic blocks, scopes of value operands must be regarded as the scope
of the Phi.
The following implementations are introduced:
- Transformation and fuzzer pass for expanding vector reduction.
- Unit tests to cover the instructions with different vector sizes.
Fixes#3768.
This fixes a problem where TransformationInlineFunction could lead to
distinct instructions having identical unique ids. It adds a validity
check to detect this problem in general.
Fixes#3911.
`DebugInfoManager::AddDebugValueIfVarDeclIsVisible()` adds
OpenCL.DebugInfo.100 DebugValue from DebugDeclare only when the
DebugDeclare is visible to the give scope. It helps us correctly
handle a reference variable e.g.,
{ // scope #1.
int foo = /* init */;
{ // scope #2.
int& bar = foo;
...
in the above code, we must not propagate DebugValue of `int& bar` for
store instructions in the scope #1 because it is alive only in
the scope #2.
We have an exception: If the given DebugDeclare is used for a function
parameter, `DebugInfoManager::AddDebugValueIfVarDeclIsVisible()` has
to always add DebugValue instruction regardless
of the scope. It is because the initializer (store instruction) for
the function parameter can be out of the function parameter's scope
(the function) in particular when the function was inlined.
Without this change, the function parameter value information always
disappears whenever we run the function inlining pass and
`DebugInfoManager::AddDebugValueIfVarDeclIsVisible()`.
The validity check during fuzzing and in unit tests is strengthened to
require that every block has its enclosing function as its parent.
TransformationMergeFunctionReturns is fixed so that it ensures parents
are set appropriately.
Fixes#3907.
Currently the validator, when checking an instruction is in the correct
section, always advances the current section. This means if we have an
instruction from a previous section we'll end up reporting it as invalid
in a function definition. This error is confusing.
This CL updates the validator to check if the given opcode is from a
previous layout section before advancing the current section. If it is
from a previous layout section an error is emitted.
1. DebugValue/DebugDeclare references of load/store must not change
the behaviors of the convert-local-access-chains pass
2. We have to properly set the scope and line information of new
instructions made by the convert-local-access-chains pass
Adds a virtual method, GetFreshIds(), to Transformation. Every
transformation uses this to indicate which ids in its protobuf message
are fresh ids. This means that when replaying a sequence of
transformations the replayer can obtain a smallest id that is not in
use by the module already and that will not be used by any
transformation by necessity. Ids greater than or equal to this id
can be used as overflow ids.
Fixes#3851.
This CL adds some extra new lines and context comments into the
spirv-dis output format. This CL adds:
- Blank line and '; Annotations' before decorations
- Blank line and '; Debug Information' before debug instructions
- Blank line and '; Types, variables and constants' before type section
- Blank line and '; Function <name>' before each function.
Issue #788
Fix a use-after-move (potential) bug found by the
"bugprone-use-after-move" clang-tidy check.
This is part of a Chromium-related effort (see
https://crbug.com/1122844).
The following changes are introduced:
1. Entry block might have more than one predecessor, even if it is not
a selection/loop merge block. However Apply method asserts that
there is only one predecessor. Now, IsApplicable method ensures
that there is only one predecessor.
2. In fuzzer pass we exclude both loop headers and selection headers
as potential exit blocks.
Fixes#3827.
Before this change, the replayer would return a SPIR-V binary. This
did not allow further transforming the resulting module: it would need
to be re-parsed, and the transformation context arising from the
replayed transformations was not available. This change makes it so
that after replay an IR context and transformation context are
returned instead; the IR context can subsequently be turned into a
binary if desired.
This change paves the way for an upcoming PR to integrate spirv-reduce
with the spirv-fuzz shrinker.
TransformationContext now holds a std::unique_ptr to a FactManager,
rather than a plain pointer. This makes it easier for clients of
TransformationContext to work with heap-allocated instances of
TransformationContext, which is needed in some upcoming work.
This transformation, given a constant integer (scalar or vector) C,
constants I and S of compatible type and scalar 32-bit integer constant
N, such that C = I - S*N, adds a loop which subtracts S from I, N
times, creating a synonym for C.
The related fuzzer pass randomly chooses constants to which to add
synonyms using this transformation, and the location where they should
be added.
Fixes#3616.
In preparation for some upcoming work on the shrinker, this PR changes
the interfaces of Fuzzer, Replayer and Shrinker so that all data
relevant to each class is provided on construction, meaning that the
"Run" method can become a zero-argument method that returns a status,
transformed binary and sequence of applied transformations via a
struct.
This makes greater use of fields, so that -- especially in Fuzzer --
there is a lot less parameter passing.
This change introduces various strategies for controlling the manner
in which fuzzer passes are applied repeatedly, including infrastructure
to allow fuzzer passes to be recommended based on which passes ran
previously.
This PR modifies the FactManager methods IdIsIrrelevant and GetIrrelevantIds so
that an id is always considered irrelevant if it comes from a dead block.
Fixes#3733.
Introduces two changes:
- duplicated_exit_region refers to a correct block, regardless of the order
of the blocks in the enclosing function.
- Exclude the case where the continue target is the exit block.
This PR extends the RandomGenerator interface and fixes the
PseudoRandomGenerator class. It:
- Fixes a problem that made the RandomUint32 of PseudoRandomGenerator
segfault.
- Adds the RandomUint64 function to RandomGenerator and
PseudoRandomGenerator.
Fixes#3805.
This PR implements part of the add bit instruction synonym transformation.
For now, the implementation covers the OpBitwiseOr, OpBitwiseXor and
OpBitwiseAnd cases.
This PR changes the fact manager so that, when calling some of the
functions in submanagers, passes references to other submanagers if
necessary (e.g. to make consistency checks).
In particular:
- DataSynonymAndIdEquationFacts is passed to the AddFactIdIsIrrelevant
function of IrrelevantValueFacts
- IrrelevantValueFacts is passed to the AddFact functions of
DataSynonymAndIdEquationFacts
The IRContext is also passed when necessary and the calls to the
corresponding functions in FactManager were updated to be valid and
always use an updated context.
Fixes#3550.
This transformation, given the header of a selection construct with
branching instruction OpBranchConditional, flattens it.
Side-effecting operations such as OpLoad, OpStore and OpFunctionCall
are enclosed within smaller conditionals.
It is applicable if the construct does not contain inner selection
constructs or loops, or atomic or barrier instructions.
The corresponding fuzzer pass looks for selection headers and
tries to flatten them.
Needed for the issue #3544, but it does not fix it completely.
In #3636, I missed that the instruction folder may create more than a
single constant per call. Since CCP was only checking whether one
constant had been created after folding, it was wrongly thinking that
the IR had not changed.
Fixes#3738.
Adds a transformation that inserts a conditional statement with a
boolean expression of arbitrary value and duplicates a given
single-entry, single-exit region, so that it is present in each
conditional branch and will be executed regardless of which branch will
be taken.
Fixes#3614.
Motivated by integrating spirv-reduce into spirv-fuzz, so that an
added function can be made smaller during shrinking, this adds support
in spirv-reduce for asking reduction to be restricted to the
instructions of a single specified function.
Avoids the use of "using" in favour of explicit qualification, to be
consistent with spirv-fuzz. Fixes indentation in a TODO comment.
Addresses and removes two existing TODO comments by moving some helper
functionality into reduction_util.
Related issue: #2184.
This change improves spirv-fuzz CMake code to be more compatible with other projects that might want to include spirv-fuzz as a sub-project.
* Add a CMake option for building spirv-fuzz.
* We now check if protobuf targets are already available.
* We no longer specify `-DGOOGLE_PROTOBUF_NO_RTTI -DGOOGLE_PROTOBUF_USE_UNALIGNED=0`; a newer version of protobuf does not require this. Note that we probably should have specified this for protobuf targets as well, but this is no longer needed.
* Updated protobuf version in Kokoro scripts and README.md.
This PR adds the NestingDepth function to StructuredCFGAnalysis.
This function, given a block id, returns the number of merge
constructs containing it.
This is needed by spirv-fuzz, but it makes sense to add it to
StructuredCFGAnalaysis, which contains related functionalities.
This transformation takes an OpSelect instruction and replaces it with
a conditional branch, selecting the correct value using an OpPhi
instruction.
Fixes part of the issue #3544.
The Vulkan 1.2.152 headers/spec now include Valid Usage IDs (VUID)
for every BuiltIn. This change adds labeling to help aid tracking
the coverage gap in Vulkan targeted validation. This is done with
a script in the Validation Layers that parses the source for VUID
strings, both that there is an implementation and a test for it.
There are 2 main changes:
1. A VUID string is added where applicable. It is wrapped in a function
that at runtimes checks if Vulkan is the target so that other targets
will not be effected as the output error only changes for Vulkan and
the overhead only occurs if there is an error at all.
2. For unit test, a new parameter value was added to allow make sure
that for each VUID there is a matching test. There are cases where the
same unit test checks multiple VUs via the parameter feature of gtest.
For this, I added a custom gMock Matcher to simply loop over a list
of VUID strings
Pointer (if VariablePointers is enabled) to find sets of potential
synonyms.
However, some instructions with these types cannot be used in an OpPhi:
- OpFunction cannot be used as a value
- OpUndef should not be used, because it yields an undefined value for
each use
Fixes#3761.
This transformation takes the id of an OpPhi instruction, of a dead
predecessor of the block containing it and a replacement id of
available to use and of the same type as the OpPhi, and changes
the id in the OpPhi corresponding to the given predecessor.
For example, %id = OpPhi %type %v1 %p1 %v2 %p2
becomes %id = OpPhi %type %v3 %p1 %v2 %p2
if the transformation is given %id, %p1 and %v3, %p1 is a dead block,
%v3 is type type and it is available to use at the end of %p1.
The fuzzer pass randomly decides to apply the transformation to OpPhi
instructions for which at least one of the predecessors is dead
Fixes#3726.
A transformation that replaces the use of an irrelevant id with
another id of the same type.
The related fuzzer pass, for every use of an irrelevant id,
checks whether the id can be replaced in that use by another
id of the same type and randomly decides whether to replace
it.
Fixes#3503.
This PR extends CallGraph with functions to return:
- a list of functions in lexicographical order, with respect to
function calls
- the maximum loop nesting depth that a function can be called from
(computed interprocedurally, e.g. if foo() calls bar() at depth 2
and bar() calls baz() at depth 1, the maximum depth of baz() will
be 3).
When we update OpenCL.DebugInfo.100 lexical scopes e.g., DebugFunction,
we have to replace DebugScope of each instruction that uses the lexical
scope correctly.
There's no real need for Fuzzer, Replayer and Shrinker to use the
opaque pointer design pattern. This change removes it, paving the way
for making some upcoming changes to Fuzzer easier.
A transformation that adds new OpPhi instructions to blocks with >=1
predecessors, so that its value depends on previously-defined ids of
the right type, which are all synonymous. This instruction is also
recorded as synonymous to the others.
The related fuzzer pass still needs to be implemented.
Fixes#3592 .
This change adds the notion of "overflow ids", which can be used
during shrinking to facilitate applying transformations that would
otherwise have become inapplicable due to earlier transformations
being removed.
It is possible that the result of a void function call is used. In case
it is used, we need something that still defines its id after inlining.
We use an undef for that purpose.
Fixes https://github.com/KhronosGroup/SPIRV-Tools/issues/3704
CCP should mark IR changed if it created new constants.
This fixes#3636.
When CCP is simulating statements, it will sometimes successfully fold
an instruction, which laters switches to varying. The initial fold of
the instruction may generate a new constant K.
The problem we were running into is when K never gets propagated to the
IR. Its definition will still exist, so CCP should mark the IR modified
in this case.
In fixing this bug, I noticed that an existing test was suffering from
the same bug. The change also makes PassTest::SinglePassRunAndMatch()
return the result from the pass, so that we can check that the pass
marks the IR modified in this case.
Adds FuzzerPassAddCompositeInserts, which randomly adds new
OpCompositeInsert instructions. Each OpCompositeInsert instruction
yields a copy of an original composite with one subcomponent replaced
with an existing or newly added object. Synonym facts are added for the
unchanged components in the original and added composite, and for the
replaced subcomponent and the object, if possible.
Fixes#2859
For FuzzerPassAddParameters, adds pointer types (that have the storage
class Function or Private) to the pool of available types for new
parameters. If there are no variables of the chosen pointer type, it
invokes TransformationAddLocalVariable / TransformationAddGlobalVariable
to add one.
Part of #3403
In the existing code, ADCE pass does not check DebugScope of an
instruction when it checks the users of each instruction, which results
in removing OpenCL.Debug.100 instructions that are only used by
DebugScope. This commit lets ADCE pass add DebugScope of an instruction
to the live instruction set when the instruction is added to the live
instruction set.
The FuzzerPassDonateModules was not checking if the function to donate had
a block with OpKill or OpUnreachable as its termination instruction.
Fixes#3709.
`TransformationAddDeadBlock` did not check whether the existing block
(that will become a selection header) dominates its successor block (that
will become its merge block).
This change adds the check.
Fixes#3690.
Some OpenCL.DebugInfo.100 instructions such as DebugGlobalVariable
and DebugLocalVariable have the Type operand. This commit allows them to
use DebugTypeTemplate for the Type operand.
Improves the code coverage of tests for the following transformations:
1. TransformationAddRelaxedDecoration
2. TransformationReplaceCopyMemoryWithLoadStore
3. TransformationReplaceCopyObjectWithStoreLoad
4. TransformationReplaceLoadStoreWithCopyMemory
5. TransformationReplaceAddSubMulWithCarryingExtended
This PR introduces FuzzerPassAddLoopPreheaders, which:
- Finds existing loop headers
- If they have no simple preheader (where simple means that the
preheader itself is not a loop header), randomly decides whether
to add one.
Fixes#3621.
Support identical predecessors in TransformationPropagateInstructionUp.
A basic block may have multiple identical predecessors as follows:
%1 = OpLabel
OpSelectionMerge %2 None
OpBranchConditional %true %2 %2
%2 = OpLabel
...
This case wasn't supported before.
* No longer blindly add global non-semantic info instructions to global
types and values
* functions now have a list of non-semantic instructions that succeed
them in the global scope
* global non-semantic instructions go in global types and values if
they appear before any function, otherwise they are attached to the
immediate function predecessor in the module
* changed ADCE to use the function removal utility
* Modified EliminateFunction to have special handling for non-semantic
instructions in the global scope
* non-semantic instructions are moved to an earlier function (or full
global set) if the function they are attached to is eliminated
* Added IRContext::KillNonSemanticInfo to remove the tree of
non-semantic instructions that use an instruction
* this is used in function elimination
* There is still significant work in the optimizer to handle
non-semantic instructions fully in the optimizer
`TransformationAddTypeFloat` and `TransformationAddTypeInt` did not check whether the required capabilities were present when adding 16-bit, 64-bit, and 8-bit types.
This change adds these checks in the `IsApplicable` method of each transformation.
Fixes#3669.
`TransformationReplaceIdWithSynonym` is careful to avoid replacing id uses that index into a struct with synonyms because the indices must only be `OpConstant` instructions. However, the check only considered `OpAccessChain` instructions, even though the same restriction applies to `OpInBoundsAccessChain`, `OpPtrAccessChain`, etc.
This change extends the check to include all access chain instructions.
Fixes#3671.
`FuzzerPassInterchangeSignednessOfIntegerOperands` and `FuzzerPassInterchangeZeroLikeConstants` both included specialization constants when trying to find integer constants with known values. However, this is incorrect behavior because we do not know the value of specialization constants. Furthermore, ConstantManager does not support them, and this led to crashes where we assumed we could look up specialization constants via the ConstantManager.
This change fixes both passes to ignore specialization constants.
Fixes#3663.
spvtools::fuzz::MakeIdUseDescriptorFromUse asserts if the id use type is
SPV_OPERAND_TYPE_ID. The problem is that not all id types are covered by
this condition. The bug was found because the first operand of an OpControlBarrier
instruction has SPV_OPERAND_TYPE_SCOPE_ID as type. Therefore, to cover
all cases the spvIsInIdType function is used.
Fixes#3665.
Given an instruction (that may use an OpPhi result from the same block as an input operand), try to clone the instruction into each predecessor block, replacing the input operand with the corresponding OpPhi input operand in each case, if necessary.
Fixes#3458.
Replaces OpIAdd with OpIAddCarry, OpISub with OpISubBorrow, OpIMul with
OpUMulExtended or OpSMulExtended and stores the result into a fresh_id
representing a structure. Extracts the first element of the result into
the original result_id. This value is the same as the result of the
original instruction.
Fixes#3577
This PR changes the way FuzzerPassReplaceLinearAlgebraInstructions iterates over the module instructions. It avoids iterating over non-relevant instructions (globals, types, etc.).
This PR changes FuzzerPassOutlineFunctions so that it uses some
transformation that make the TransformationOutlineFunction
transformation applicable in more cases. See the discussion in
#3095 for more details.
Fixes#3095.
The updated OpenCL.DebugInfo.100 spec says that we can use
variable for "Component Count" operand of DebugTypeArray i.e.,
DebugLocalVariable or DebugGlobalVariable. This commit updates spirv-val
based on the spec update.
For each local variable, ssa-rewrite should remove its DebugDeclare
if and only if it is replaced by any number of DebugValues for store
and phi instructions.
For example, when we have two variables `a` whose DebugDeclare
will be replaced to DebugValues by ssa-rewrite pass and `b` whose
DebugDeclare will not be replaced, we have to remove only DebugDeclare
for `a`, not `b`.
This PR introduces TransformationAddLoopPreheader, which, given
a loop header and enough fresh ids, adds a loop preheader, updating
all the references so that this new block is the only out-of-loop
predecessor of the header, which branches unconditionally to the
header.
See the discussion in #3095.
This PR introduces a new fuzzer pass, which:
- finds all integer vectors or constants
- finds or creates the corresponding constants with opposite
signedness
- records such constants as synonyms of the first ones
- replaces the usages of the original constants with the new ones
if allowed
Fixes#2677.
When we copy the loop body to unroll it, we have to copy its
instructions but DebugDeclare or DebugValue used for the declaration
i.e., DebugValue with Deref must not be copied and only the first block
can contain those instructions.
* Generate ext inst table for reflection
* Change build to use grammar files from SPIRV-Headers instead of
SPIRV-Tools
* Add enum for clspv reflection extended instruction set
* count it as non-semantic
* validate clspv reflection extended instruction set
* Remove local extended inst sets
* update headers deps
* Update nbuilds to use grammars from SPIRV-Headers instead of
local duplicates
Rename the `${SPIRV_TOOLS}` target to `${SPIRV_TOOLS}-static` and alias `${SPIRV_TOOLS}` to either `${SPIRV_TOOLS}-static` or `${SPIRV_TOOLS}-shared` depending on `BUILD_SHARED_LIBS`.
Re-point all internal uses of `${SPIRV_TOOLS}` to `${SPIRV_TOOLS}-static`.
`${SPIRV_TOOLS}-static` is explicitly renamed to just `${SPIRV_TOOLS}` to ensure the name does not change from current behavior.
Build the `SPIRV-Tools-*` libraries as static, as this is what they always were.
Force the external targets `gmock` and `effcee` to be built statically. These either do not support being built as shared libraries, or require special flags.
Issue: #3482
* Avoid operand type range checks
Deprecates the SPV_OPERAND_TYPE_FIRST_* and SPV_OPERAND_TYPE_LAST_*
macros.
The "variable" and "optional" operand types are only for internal use.
Export spvOperandIsConcrete instead, as that should cover intended
external uses.
Test that each operand type is classified either as one of:
- a sentinel value
- a concrete operand type
- an optional operand type (which includes variable-expansion types)
Test that each concrete and optional non-variable operand type
has a name for use internally when generating messages.
Co-authored-by: Steven Perron <stevenperron@google.com>
1. Set the debug scope and line information for the new replacement
instructions.
2. Replace DebugDeclare and DebugValue if their OpVariable or value
operands are replaced by scalars. It uses 'Indexes' operand of
DebugValue. For example,
struct S { int a; int b;}
S foo; // before scalar replacement
int foo_a; // after scalar replacement
int foo_b;
DebugDeclare %dbg_foo %foo %null_expr // before
DebugValue %dbg_foo %foo_a %Deref_expr 0 // after
DebugValue %dbg_foo %foo_b %Deref_expr 1 // means Value(foo.members[1]) == Deref(%foo_b)
* spirv-val: Pipes are no longer required for OpenCL 1.2 EP
This was removed from the OpenCL SPIR-V Environment Specification via
https://github.com/KhronosGroup/OpenCL-Docs/pull/56.
* spirv-val: Sort headers according to clang-format
* spirv-val: Groups capability is required since OpenCL 2.0
Adds a transformation that takes a pair of instruction descriptors to
OpLoad and OpStore that have the same intermediate value and replaces
the OpStore with an equivalent OpCopyMemory.
Fixes#3353.
Right now, TransformationRecordSynonymousConstants requires the type
ids of two candidate constants to be exactly the same.
This PR adds an exception for integer constants, which can be
considered equivalent even if their signedness is different.
This applies to both integers and vector constants.
The IsApplicable method of ReplaceIdWithSynonym is also updated so
that, in the case of two integer constants which don't have the same
type, they can only be swapped in particular instructions (those
that don't take the signedness into consideration).
Fixes#3536.
This PR generalises TransformationAddAccessChain so that dynamic
indices for non-struct composites (with clamping to ensure that
accesses are in-bound) are allowed.
The transformation will add instructions to clamp any index to
a non-struct composite, regardless of whether it is a constant
or not.
Fixes#3179.
This PR modifies FuzzerPassOutlineFunctions so that it tries to split
a block starting with OpPhi instructions, so that it is more likely
that the selected blocks can be outlined using
TransformationOutlineFunction.
Fixes#3094.
Fixes an issue with the shrinker, where the message consumer set for
the shrinker was not being passed on to the replay object that the
shrinker creates. This meant that messages generated during replay
would cause an exception to be thrown.
Adds a transformation that replaces instruction OpCopyMemory with
loading the source variable to an intermediate value and storing this
value into the target variable of the original OpCopyMemory instruction.
Fixes#3352
Adds a transformation that replaces instruction OpCopyObject with
storing into a new variable and immediately loading this variable to
|result_id| of the original OpCopyObject instruction.
Fixes#3351.
Essentially, it marks all DebugInfo instructions in functions (and their operands) as live. It treats DebugDeclare and DebugValue with Deref as loads and so marks Stores of their variables as live.
It marks each DebugGlobalVariables as live except for its variable. After closure, it rechecks if the variable is live. If not, the DebugGlobalVariable instruction's variable operand is set to DebugInfoNone, per the DebugInfo spec.
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
Now that WebGPU ingests WGSL instead of SPIR-V,
there is no need to be so strict about the memory model.
Allow any memory model that is already allowed by Vulkan 1.0,
either directly or via an existing.
Fixes#3529
* Make BasicBlock::reachable() only consider static reachability
* Fix reachability calculation to be independent of block order
* add tests
This fuzzer pass:
For each zero-like constant, either finds the existing definition of
the corresponding toggled one (OpConstantNull becomes zero-valued
scalar OpConstant or vice versa) or creates a new one if it doesn't
exist and records that the two are synonyms
For each use of these constants, probabilistically decides whether to
change it with the corresponding toggled constant id (as described in
#3486 )
Only uses inside blocks of instructions are considered and not, for
example, in instructions declaring other constants.
This pass basically follows the same process as ssa-rewrite: it adds a DebugValue after each Store and removes the DebugDeclare or DebugValue Deref. It only does this if all instructions that are dependent on the Store are Loads and are replaced.
This commit lets the vector DCE pass preserve the OpenCL.DebugInfo.100
information properly. When the vector DCE pass determines the liveness
of instructions, the debug instructions must not affect the decision. In
addition, when it kills some instructions, it has to kill DebugValue
instructions that use the killed instructions. When it updates some
composite values to meaningful values (not undef), it has to remove
DebugValue because the value information becomes incorrect.
The decision to reduce the load must be not affected by debug
instructions. For example, even when a DebugValue references a
result id of a loaded composite value, this change lets the
reduce-load-size pass reduce the load if the full composite value is not
used anywhere other than the DebugValue.
