Within each function that launches tasks, we now can easily track which
tasks that function launched, so that the sync at the end of the function
can just sync on the tasks launched by that function (not all tasks
launched by all functions.)
Implementing this led to a rework of the task system API that ispc generates
code to call; the example task systems in examples/tasksys.cpp have been
updated to conform to this API. (The updated API is also documented in
the ispc user's guide.)
As part of this, "launch[n]" syntax was added to launch a number of tasks
in a single launch statement, rather than requiring a loop over 'n' to
launch n tasks.
This commit thus fixes issue #84 (enhancement to launch multiple tasks from
a single launch statement) as well as issue #105 (recursive task launches
were broken).
This way, we match C/C++ in that casting a bool to an int gives either the value
zero or the value one. There is a new stdlib function int sign_extend(bool)
that does sign extension for cases where that's desired.
Fixes bug #55. A number of tests were crashing on Windows due to the task
launch code using alloca to allocate space for the tasks' parameters. On
Windows, the stack isn't generally big enough for this to be a good idea.
Also added an alignment parmaeter to ISPCMalloc() to pass the alignment
requirement along.
This checkin provides the standard set of atomic operations and a memory barrier in the ispc standard library. Both signed and unsigned 32- and 64-bit integer types are supported.
When creating function Symbols for functions that were defined in LLVM bitcode for the standard library, if any of the function parameters are integer types, create two ispc-side Symbols: one where the integer types are all signed and the other where they are all unsigned. This allows us to provide, for example, both store_to_int16(reference int a[], uniform int offset, int val) as well as store_to_int16(reference unsigned int a[], uniform int offset, unsigned int val). functions.
Added some additional tests to exercise the new variants of these.
Also fixed some cases where the __{load,store}_int{8,16} builtins would read from/write to memory even if the mask was all off (which could cause crashes in some cases.)
scalar values (that ispc used to smear across the array/struct
elements). Now, initializers in variable declarations must be
{ }-delimited lists, with one element per struct member or array
element, respectively.
There were a few problems with the previous implementation of the
functionality to initialize from scalars. First, the expression
would be evaluated once per value initialized, so if it had side-effects,
the wrong thing would happen. Next, for large multidimensional arrays,
the generated code would be a long series of move instructions, rather
than loops (and this in turn made LLVM take a long time.)
While both of these problems are fixable, it's a non-trivial
amount of re-plumbing for a questionable feature anyway.
Fixes issue #50.
