[polly] Add diagnostic remark for ReportVariantBasePtr

[Tobias Grosser]

On 26/06/2014 23:06, Andreas Simbuerger wrote:
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> - --- examples/polli » pclang -S -g -gcolumn-info -emit-llvm -O3 -mllvm
> - -polly-detect-track-failures -mllvm -polly-detect-keep-going -mllvm
> - -polly -Xclang -Rpass-missed="polly-detect" -c tobi-scop.c
> tobi-scop.c:6:8: remark: The following errors keep this region from
> being a Scop.
>        [-Rpass-missed=polly-detect]
>    for (int i = 0; i < 32; i++)
>         ^
> tobi-scop.c:7:5: remark: The base address of this array is not
> invariant inside the loop
>        [-Rpass-missed=polly-detect]
>      A->b[i] = A->b[i + 1];
>      ^
> tobi-scop.c:7:5: remark: The base address of this array is not
> invariant inside the loop
>        [-Rpass-missed=polly-detect]
>
> In this case here I have -Rpass-missed -g -gcolumn-info specified.
>
> I would expect the first remark pinned at line 7 column 5
> and the second remark pinned at the read in line 7 column 17.
>
> However, the IR only contains dbg nodes for line 7 column 5 inside the
> loop body. Tobi's patch further up in the thread fixes it.

To add relevant information to this thread, Diego committed 
-gcolumn-info in r212781, so our caret diagnostic is now at the right place.

clang still does not emit separate debug locations for individual 
loads/stores. We could now add this on top of -gcolumn-info.

Cheers,
Tobias