We now have separate Expr implementations for dereferencing pointers
and automatically dereferencing references. This is in particular
necessary so that we can detect attempts to dereference references
with the '*' operator in programs and issue an error in that case.
Fixes issue #192.
safe: indicates that the function can safely be called with an "all off"
execution mask.
costN: (N an integer) overrides the cost estimate for the function with
the given value.
There's now a SOA variability class (in addition to uniform,
varying, and unbound variability); the SOA factor must be a
positive power of 2.
When applied to a type, the leaf elements of the type (i.e.
atomic types, pointer types, and enum types) are widened out
into arrays of the given SOA factor. For example, given
struct Point { float x, y, z; };
Then "soa<8> Point" has a memory layout of "float x[8], y[8],
z[8]".
Furthermore, array indexing syntax has been augmented so that
when indexing into arrays of SOA-variability data, the two-stage
indexing (first into the array of soa<> elements and then into
the leaf arrays of SOA data) is performed automatically.
Previously, we uniqued AtomicTypes, so that they could be compared
by pointer equality, but with forthcoming SOA variability changes,
this would become too unwieldy (lacking a more general / ubiquitous
type uniquing implementation.)
Now, the pointed-to type is always uniform by default (if an explicit
rate qualifier isn't provided). This rule is easier to remember and
seems to work well in more cases than the previous rule from 6d7ff7eba2.
Now, if a struct member has an explicit 'uniform' or 'varying'
qualifier, then that member has that variability, regardless of
the variability of the struct's variability. Members without
'uniform' or 'varying' have unbound variability, and in turn
inherit the variability of the struct.
As a result of this, now structs can properly be 'varying' by default,
just like all the other types, while still having sensible semantics.
Now, if rate qualifiers aren't used to specify otherwise, varying
pointers point to uniform types by default. As before, uniform
pointers point to varying types by default.
float *foo; // varying pointer to uniform float
float * uniform foo; // uniform pointer to varying float
These defaults seem to require the least amount of explicit
uniform/varying qualifiers for most common cases, though TBD if it
would be easier to have a single rule that e.g. the pointed-to type
is always uniform by default.
If the initializer is a compile-time constant (or at least a part of it
is), then store the constant value in a module-local constant global
value and then memcpy the value into the variable. This, in turn,
turns into much better assembly in the end.
Issue #176.
We now match C's behavior, where if we have an initializer list with
too-few values for the underlying type, any additional elements are
initialized to zero.
Fixes issue #123.
Specifically, if both of the expressions are compile-time constants
and the condition is a varying compile-time constant (even if not
all true or all false), then we can assemble a compile-time constant
result.
? : now short-circuits evaluation of the expressions following
the boolean test for varying test types. (It already did this
for uniform tests).
Issue #169.
Also reworked TypeCastExpr::GetConstant() to just forward the request along
and moved the code that was previously there to handle uniform->varying
smears of function pointers to FunctionSymbolExpr::GetConstant().
Fixes issue #168.
We now follow C's approach of evaluating these: we don't evaluate
the second expression in the operator if the value of the first one
determines the overall result. Thus, these can now be used
idiomatically like (index < limit && array[index] > 0) and such.
For varying expressions, the mask is set appropriately when evaluating
the second expression.
(For expressions that can be determined to be both simple and safe to
evaluate with the mask all off, we still evaluate both sides and compute
the logical op result directly, which saves a number of branches and tests.
However, the effect of this should never be visible to the programmer.)
Issue #4.
Now, when a type is declared without an explicit "uniform" or "varying"
qualifier, its variability is unbound; depending on the context of the
declaration, the variability is later finalized.
Currently, in almost all cases, types with unbound variability are
resolved to varying types; the one exception is typecasts like:
"(int)1"; in this case, the fact that (int) has unbound variability
carries through to the TypeCastExpr, which in turn notices that the
expression being type cast has uniform type and in turn will resolve
(int) to (uniform int).
Fixes issue #127.
Specifically, we want to be able to late-bind on whether the mask is i32s or i1s, so if there's
any chance of ambiguity, we emit code that does the "GEP from a NULL base pointer" trick to
compute the value later in compilation.
Specifically, stmts and exprs are no longer responsible for first recursively
optimizing their children before doing their own optimization (this turned
out to be error-prone, with children sometimes being forgotten.) They now
are just responsible for their own optimization, when appropriate.
We should always use the full mask when storing to a reference, since we
don't in general know what it refers to (and thence the appropriate mask
to use for its target).
(Somehow this wasn't being done before.)
Errors are now issued if too few arguments are used when calling through
a function pointer, too many arguments are used, or if any of them can't be
type converted to the parameter type.
