[Bug libstdc++/113376] Confusing notes when using C++17 parallel algorithms
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113376 --- Comment #6 from Jonathan Wakely --- (In reply to Pilar Latiesa from comment #3) > It seems that what is missing is a corresponding change in the macro > definition logic. It should have been changed to: > > // Check the user-defined macro for warnings > #if defined(PSTL_USAGE_WARNINGS) > #define _PSTL_USAGE_WARNINGS > #endif > > See > https://github.com/llvm/llvm-project/blob/ > 5ccf19ded09f68bef43275c81c20b0e65f7c0b75/pstl/include/pstl/internal/ > pstl_config.h#L26 The upstream change breaks the previous API though. It looks like users were able to define PSTL_USAGE_WARNINGS=0 or PSTL_USAGE_WARNINGS=1 to request warnings to be off or on, respectively. But the LLVM change means that it only matters whether it's defined or not. This seems to have been a misguided change to make sure *all* macros are used with #ifdef not #if. But that breaks the intended use for some of them. So I think we should either revert the change later in the file which checks _PSTL_USAGE_WARNINGS, or we should take the user-facing macro's value into account when deciding whether to define it: // Check the user-defined macro for warnings #if defined(PSTL_USAGE_WARNINGS) && PSTL_USAGE_WARNINGS != 0 #define _PSTL_USAGE_WARNINGS #endif
[Bug libstdc++/113376] Confusing notes when using C++17 parallel algorithms
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113376 --- Comment #5 from Jonathan Wakely --- I think https://github.com/llvm/llvm-project/commit/3b9a1bb1af90db9472340ef2122d3855eb9ba3fc#r142768040 is the real cause of the problem. They wanted to avoid -Wundef errors, so changed all the macro tests to use #ifdef instead of #if That is what requires a change to how _PSTL_USAGE_WARNINGS is defined. It also caused other problems elsewhere downstream: https://github.com/oneapi-src/oneDPL/issues/1602
[Bug libstdc++/113376] Confusing notes when using C++17 parallel algorithms
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113376 --- Comment #4 from Jonathan Wakely --- https://github.com/llvm/llvm-project/commit/c4823cc5db69f16bb5c96cf7d1b0d070da83605e changed the logic upstream, but it looks like that didn't come downstream with r14-2109-g3162ca09dbdc2e
[Bug libstdc++/113376] Confusing notes when using C++17 parallel algorithms
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113376 --- Comment #3 from Pilar Latiesa --- It seems that what is missing is a corresponding change in the macro definition logic. It should have been changed to: // Check the user-defined macro for warnings #if defined(PSTL_USAGE_WARNINGS) #define _PSTL_USAGE_WARNINGS #endif See https://github.com/llvm/llvm-project/blob/5ccf19ded09f68bef43275c81c20b0e65f7c0b75/pstl/include/pstl/internal/pstl_config.h#L26
[Bug libstdc++/113376] Confusing notes when using C++17 parallel algorithms
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113376 --- Comment #2 from Jonathan Wakely --- (In reply to Pilar Latiesa from comment #1) > (In reply to Pilar Latiesa from comment #0) > > I don't understand why all these functions are even instantiated as they > > appear to be related to the vectorization of other algorithms. > > Pragma messages are shown irrespectively of whether the function is > instantiated. Yeah, I don't know if Clang works differently (I don't think so?) or if those pragmas are just misused. They come from the upstream PSTL project. > > > i.e. is checking defined(_PSTL_USAGE_WARNINGS) instead of just > > _PSTL_USAGE_WARNINGS. This logic doesn't seem right. > > This change was made as part of r14-2109-g3162ca09dbdc2e: > > - #if _PSTL_USAGE_WARNINGS > + #if defined(_PSTL_USAGE_WARNINGS) > > I don’t think this change is correct. Good catch.
[Bug libstdc++/113376] Confusing notes when using C++17 parallel algorithms
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113376 --- Comment #1 from Pilar Latiesa --- (In reply to Pilar Latiesa from comment #0) > I don't understand why all these functions are even instantiated as they > appear to be related to the vectorization of other algorithms. Pragma messages are shown irrespectively of whether the function is instantiated. > i.e. is checking defined(_PSTL_USAGE_WARNINGS) instead of just > _PSTL_USAGE_WARNINGS. This logic doesn't seem right. This change was made as part of r14-2109-g3162ca09dbdc2e: - #if _PSTL_USAGE_WARNINGS + #if defined(_PSTL_USAGE_WARNINGS) I don’t think this change is correct.
[Bug libstdc++/113376] Confusing notes when using C++17 parallel algorithms
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113376 Jonathan Wakely changed: What|Removed |Added Last reconfirmed||2024-01-13 Ever confirmed|0 |1 Status|UNCONFIRMED |NEW CC||rodgertq at gcc dot gnu.org
