These make it easier to iterate over arbitrary amounts of data
elements; specifically, they automatically handle the "ragged
extra bits" that come up when the number of elements to be
processed isn't evenly divided by programCount.
TODO: documentation
Specifically, indexing into global arrays sometimes comes in as a big
llvm::ConstantVector, so we need to handle traversing those as well when
we do the corresponding checks in GatherScatterFlattenOpt so that we
still detect cases where we can convert them into the base pointer +
offsets form that's used in later analysis.
The packed_{load,store}_active now functions take a pointer to a
location at which to start loading/storing, rather than an array
base and a uniform index.
Variants of the prefetch functions that take varying pointers
are now available.
There are now variants of the various atomic functions that take
varying pointers (issue #112).
The launch group handle is now reset to NULL after sync is called;
this ensures that if tasks are launched in the same function after
a sync, that the ISPCAlloc() call for the next launch will be
passed a NULL handle (as it should be).
Allow <, <=, >, >= comparisons of pointers
Allow explicit type-casting of pointers to and from integers
Fix bug in handling expressions of the form "int + ptr" ("ptr + int"
was fine).
Fix a bug in TypeCastExpr where varying -> uniform typecasts
would be allowed (leading to a crash later)
Given IR that encoded computation like "vec(4) + ptr2int(some pointer)",
we'd report that "int2ptr(4)" was the base pointer and the ptr2int
value was the offset. This in turn could lead to incorrect code
from LLVM, since we'd end up with GEP instructions where the first
operand was int2ptr(4) and the offset was the original pointer value.
This in turn was sometimes leading to incorrect code and thence a
failure on the tests/gs-double-improve-multidim.ispc test since LLVM's
memory read/write analysis assumes that nothing after the first operand
of a GEP is actually a pointer.
Allow atomic types to be initialized with single-element expression lists:
int x = { 5 };
Issue an error if a storage class is provided with a function parameter.
Issue an error if two members of a struct have the same name.
Issue an error on trying to assign to a struct with a const member, even if
the struct itself isn't const.
Issue an error if a function is redefined.
Issue an error if a function overload is declared that differs only in return
type from a previously-declared function.
Issue an error if "inline" or "task" qualifiers are used outside of function
declarations.
Allow trailing ',' at the end of enumerator lists.
Multiple tests for all of the above.
Pointers can be either uniform or varying, and behave correspondingly.
e.g.: "uniform float * varying" is a varying pointer to uniform float
data in memory, and "float * uniform" is a uniform pointer to varying
data in memory. Like other types, pointers are varying by default.
Pointer-based expressions, & and *, sizeof, ->, pointer arithmetic,
and the array/pointer duality all bahave as in C. Array arguments
to functions are converted to pointers, also like C.
There is a built-in NULL for a null pointer value; conversion from
compile-time constant 0 values to NULL still needs to be implemented.
Other changes:
- Syntax for references has been updated to be C++ style; a useful
warning is now issued if the "reference" keyword is used.
- It is now illegal to pass a varying lvalue as a reference parameter
to a function; references are essentially uniform pointers.
This case had previously been handled via special case call by value
return code. That path has been removed, now that varying pointers
are available to handle this use case (and much more).
- Some stdlib routines have been updated to take pointers as
arguments where appropriate (e.g. prefetch and the atomics).
A number of others still need attention.
- All of the examples have been updated
- Many new tests
TODO: documentation
Added support for resolving dimensions of multi-dimensional unsized arrays
from their initializer exprerssions (previously, only the first dimension
would be resolved.)
Added checks to make sure that no unsized array dimensions remain after
doing this (except for the first dimensision of array parameters to
functions.)
Substantial improvements and generalizations to the parsing and
declaration handling code to properly parse declarations involving
pointers. (No change to user-visible functionality, but this
lays groundwork for supporting a more general pointer model.)
Previously, to compute the size of objects and the offsets of struct
elements within structs, we were using the trick of using getelementpointer
with a NULL base pointer and then casting the result to an int32/64.
However, since we actually know the target we're compiling for at
compile time, we can use corresponding methods from TargetData to
get these values directly.
This mostly cleans up code, but may make some of the gather/scatter
lowering to loads/stores optimizations work better in the presence
of structures.
Now, the Linker::LinkModules() call doesn't link in any functions
marked as 'internal', which is problematic, since we'd like to have
just about all of the builtins marked as internal so that they are
eliminated after they've been inlined when they are in fact used.
This change removes all of the internal qualifiers in the builtins
and adds a lSetInternalFunctions() routine to builtins.cpp that
sets this property on the functions that need it after they've
been linked in by LinkModules().
Both uniform and varying function pointers are supported; when a function
is called through a varying function pointer, each unique function pointer
value across the running program instances is called once for the set of
active program instances that want to call it.
Be better about tracking the full extent of expressions in the parser;
this leads to more intelligible error messages when we indicate where
exactly the error happened.
Previously, it was only in the GatherScatterFlattenOpt optimization pass that
we added the per-lane offsets when we were indexing into varying data.
(Specifically, the case of float foo[]; int index; foo[index], where foo
is an array of varying elements rather than uniform elements.) Now, this
is done in the front-end as we're first emitting code.
In addition to the basic ugliness of doing this in an optimization pass,
it was also error-prone to do it there, since we no longer have access
to all of the type information that's around in the front-end.
No functionality or performance change.
