Compilation warnings with GCC 8.3

[fwyzard]

Building the current HEAD with GCC 8.3 on CentOS 8 results in many compilation warnings.

The full build log is attached: build.txt .

The warnings relevant for the sycl package are already mentioned in #1572.

The warnings relevant for the libdevice package are:

In file included from /data/user/fwyzard/sycl/llvm/libdevice/fallback-cassert.cpp:9:
/data/user/fwyzard/sycl/llvm/libdevice/wrapper.h:16:1: warning: attribute declaration must precede definition [-Wignored-attributes]
DEVICE_EXTERNAL size_t __spirv_GlobalInvocationId_x();
^
/data/user/fwyzard/sycl/llvm/libdevice/device.h:28:54: note: expanded from macro 'DEVICE_EXTERNAL'                                                                                                                                                                              
#define DEVICE_EXTERNAL SYCL_EXTERNAL __attribute__((weak))
                                                    ^
/data/user/fwyzard/sycl/llvm/libdevice/spirv_vars.hpp:32:29: note: previous definition is here                                                                                                                                                                                  
SYCL_EXTERNAL inline size_t __spirv_GlobalInvocationId_x() {
                           ^

(repeated for lines 17, 18, 20, 21, 22, and repeater for other other source files)

The warnings for libclc are

/data/user/fwyzard/sycl/llvm/libclc/generic/libspirv/math/clc_ldexp.cl:40:40: warning: operator '?:' has lower precedence than '|'; '|' will be evaluated first [-Wbitwise-conditional-parentheses]
               int mr = e == 0 | v == 0 | v == 0xff ? 0 : m;
                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^
/data/user/fwyzard/sycl/llvm/libclc/generic/libspirv/math/clc_ldexp.cl:40:40: note: place parentheses around the '|' expression to silence this warning                                                                                                                         
               int mr = e == 0 | v == 0 | v == 0xff ? 0 : m;
                                                    ^
                        (                          )                                                                                                                                                                                                                           
/data/user/fwyzard/sycl/llvm/libclc/generic/libspirv/math/clc_ldexp.cl:40:40: note: place parentheses around the '?:' expression to evaluate it first                                                                                                                           
               int mr = e == 0 | v == 0 | v == 0xff ? 0 : m;
                                                    ^
                                          (                )                                                                                                                                                                                                                   

(repeated other 17 times for clc_ldexp.cl, clc_pow.cl, expm1.cl, log_base.h and sincos_helpers.cl), and

warning: Linking two modules of different data layouts: 'CMakeFiles/builtins.link.libspirv-nvptx64--nvidiacl.dir/ptx-nvidiacl/libspirv/atomic/loadstore_helpers.bc' is 'e-p:64:64-p1:64:64-p2:32:32-p3:32:32-p4:64:64-p5:32:32-p6:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-v96:
128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64-S32-A5' whereas 'llvm-link' is 'e-i64:64-i128:128-v16:16-v32:32-n16:32:64'

warning: Linking two modules of different data layouts: 'CMakeFiles/builtins.link.libspirv-nvptx64--nvidiacl.dir/ptx-nvidiacl/libspirv/cl_khr_int64_extended_atomics/minmax_helpers.bc' is 'e-p:64:64-p1:64:64-p2:32:32-p3:32:32-p4:64:64-p5:32:32-p6:32:32-i64:64-v16:16-v24:3
2-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64-S32-A5' whereas 'llvm-link' is 'e-i64:64-i128:128-v16:16-v32:32-n16:32:64'

[bader]

Most of sycl library warnings were already reported in #1572.
Could you update the existing issue instead, please?
libdevice library warnings are supposed to be addressed by #1398.
libclc is not built by GCC. It's built by clang.

I suggest leave libclc issue here and move other issues to 1572.
Are you okay with that?

[fwyzard]

Thanks for the pointer to #1572 for the sycl warnings, I will update the description of the issue to point there.

I don't see the libdevice warnings mentioned in #1398 .
Should I comment there ?

[bader]

I don't see the libdevice warnings mentioned in #1398 .
Should I comment there ?

The main goal of #1398 is to do the refactoring improving UX and code maintainability. According to my understanding, warnings should be addressed as a side effect of these changes.

Anyway, I see that you created a separate PR (#1630) to address the issue with warnings, so I guess this questions is not relevant anymore.

Thanks a lot for doing this work!

[AlexeySachkov]

@fwyzard, seems like you have submitted a PR to fix warnings, can we close this issue then?

[AlexeySachkov]

I assume that this issue is fixed and therefore closing it. @fwyzard, please speak up if there are still some warnings observable