Also, removed erroneous checks about the type of the test expression
in DoStmt and ForStmt.
These together were preventing conversion of pointer types to boolean
values, so things like "while (ptr)" would improperly not compile.
Issue #346.
All of these pass the current mask to FunctionEmitContext::SetBlockEntryMask()
so that when a break/continue/return is encountered, it can test to see if all
lanes have followed that path and then return; this in turn ensures that we never
run statements with an all-off execution mask.
These functions were passing the function internal mask, not the full mask, and
thus could end up executing code with the mask all off if some lanes were
disabled by an outer function. (The new tests test this case.)
When "break", "continue", or "return" is used under varying control flow,
we now always check the execution mask to see if all of the program
instances are executing it. (Previously, this was only done with "cbreak",
"ccontinue", and "creturn", which are now deprecated.)
An important effect of this change is that it fixes a family of cases
where we could end up running with an "all off" execution mask, which isn't
supposed to happen, as it leads to all sorts of invalid behavior.
This change does cause the volume rendering example to run 9% slower, but
doesn't affect the other examples.
Issue #257.
This fixes a crash if 'cbreak' was used in a 'switch'. Renamed
FunctionEmitContext::SetLoopMask() to SetBlockEntryMask(), and
similarly the loopMask member variable.
We need to do this since it's illegal to have nested foreach statements, but
nested foreach_unique, or foreach_unique inside foreach, etc., are all fine.
When the outermost dimension(s) were partially active, but the innermost
dimension was all on, we'd inadvertently use an incorrect "all on"
execution mask.
Fixes issues #177 and #200.
If we have a simple varying 'if' statement where the only code in the body is
a single 'break', then emit special case code that just updates the execution
mask directly.
Surprisingly, this leads to better generated code (e.g. Mandelbrot 7.1x on AVX
vs 5.8x before). It's not clear why the general code generation path for
break doesn't generate the equivalent code; this topic should be investigated
further. (Issue #277).
It can sometimes be useful to know the general place we were in the program
when an assertion hit; when the position is available / applicable, this
macro is now used.
Issue #268.
We now have a set of template functions CastType<AtomicType>, etc., that in
turn use a new typeId field in each Type instance, allowing them to be inlined
and to be quite efficient.
This improves front-end performance for a particular large program by 28%.
Both ReturnStmt and DeclStmt now check the values being associated
with references to make sure that they are legal (e.g. it's illegal
to assign a varying lvalue, or a compile-time constant to a reference
type). Previously we didn't catch this and would end up hitting
assertions in LLVM when code did this stuff.
Mostly fixes issue #225 (except for adding a FAQ about what this
error message means.)
