Displaying 2 results from an estimated 2 matches for "indvar_test".
2016 Apr 20
2
[IndVarSimplify] Narrow IV's are not eliminated resulting in inefficient code
...to kindly check and assist with the IndVarSimplify / SCEV
problem I got in the latest LLVM, please?
Sometimes IndVarSimplify may not eliminate narrow IV's when there actually
exists such a possibility. This may affect other LLVM passes and result in
inefficient code. The reproducing test 'indvar_test.cpp' is attached.
The problem is with the second 'for' loop that accesses array elements with
different indexes on each iteration.
The latest LLVM fails to reuse array element values from previous
iterations and generates an unnecessary GEP. The generated IR is shown in
the attached fi...
2016 Apr 23
2
[IndVarSimplify] Narrow IV's are not eliminated resulting in inefficient code
...the implications and whether the
> change is even correct, but the appended patch fixes the test case
> you've attached. I'll give it some more thought and if it holds up
> I'll check it in in the next few days. Meanwhile if you have a larger
> test case that you extracted indvar_test.cpp from, I'd be interested
> in hearing if this change works there as well.
>
> diff --git a/lib/Analysis/ScalarEvolution.cpp
> b/lib/Analysis/ScalarEvolution.cpp
> index 39ced1e..2e87902 100644
> --- a/lib/Analysis/ScalarEvolution.cpp
> +++ b/lib/Analysis/ScalarEvolution....