[Rd] Notes on building a gcc toolchain for Rtools (but not multilib)

[Hsiu-Khuern Tang]

On Tue, Mar 10, 2015 at 10:47 PM, Avraham Adler <avraham.adler at gmail.com> wrote:
> On Wed, Mar 11, 2015 at 1:40 AM, Hsiu-Khuern Tang <tangoh at gmail.com> wrote:
>> On Tue, Mar 10, 2015 at 8:54 PM, Avraham Adler <avraham.adler at gmail.com> wrote:
>>>
>>> I successfully rebuilt R-devel_2015-03-09 with the most recent version
>>> of Rtools tonight, building both ICU_531 and this time libcurl (7.39)
>>> as well (and OpenBLAS, of course). The internet bug is still there,
>>> but the rest of make-check all passed with flying colors, as did
>>> building 'microbenchmark' from source (with all the other needed
>>> packages, including Rcpp and Hsiu-Kheurn's change to NM was *not*
>>> used).
>>> ...
>>
>> The NM_FILTER change seems to be needed only when compiling C++ code
>> with -std=c++11 or -std=gnu++11.
>>
>> Even though the current CRAN policy doesn't allow the C++11 standard,
>> it would still be useful to document this, perhaps in the Writing R
>> Extensions manual.
>>
>> - Hsiu-Khuern
>
> Hello, Hsiu-Khuern.
>
> All the times I have built, I've passed -std-gnu++11. Specifically, I
> pass: -march=native -O3 -mfpmath=sse -std=gnu++11 -msse2avx
> -mavx256-split-unaligned-load -mavx256-split-unaligned-store
> -mvzeroupper --param l1-cache-line-size=64 --param l1-cache-size=64
> --param l2-cache-size=256.
> ...

Interesting.  I tested the use of -O0, ..., -O3 together with
-std=gnu++11.  With -O0 (which I suppose is the default if not
specified), I get the following error when R CMD INSTALL is trying to
create Rcpp.dll:

collect2.exe: error: ld returned 5 exit status

With -O1, -O2, or -O3, there is no error.

- Hsiu-Khuern