Displaying 2 results from an estimated 2 matches for "pragma_instrument_mem_add".
2010 Oct 25
4
[LLVMdev] Prevent instruction elimination
...ike a "dummy" instruction that is not removed by
the optimizers, even if it seems to be dead code?
I want to use such instructions to carry metadata information, but they
should have a minimal impact on the code generation and optimization. I used
an add instruction:
%0 = add i8 1, 2, !pragma_instrument_mem_add !0 ; <i8> [#uses=0]
which should not carry any dependencies, if inserted inside a loop for
instance. But the problem is that it is removed when I use the optimization
level -O2. Is there a way to prevent this?
I would like to attach metadata to instructions rather than using intrinsics
th...
2010 Oct 25
0
[LLVMdev] Prevent instruction elimination
...earch for MDNode in the
doxygen docs for some information on how to create metadata.
Alternatively, you can use calls to external functions. These are
seldomly optimized since optimizations assume that external functions
can have undetermined side effects.
-- John T.
> %0 = add i8 1, 2, !pragma_instrument_mem_add !0 ;<i8> [#uses=0]
>
> which should not carry any dependencies, if inserted inside a loop for
> instance. But the problem is that it is removed when I use the optimization
> level -O2. Is there a way to prevent this?
> I would like to attach metadata to instructions rather...