Messages in this thread | | | Date | Sun, 11 Aug 2002 21:07:18 +0100 | From | Jamie Lokier <> | Subject | GCC still keeps empty loops? (was: [patch 4/21] fix ARCH_HAS_PREFETCH) |
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Linus Torvalds wrote: > I thought that special case was removed long ago, because it is untenable > in C++ etc (where such empty loops happen due to various abstraction > issues, and not optimizing them away is just silly). > > But testing shows that you're right at least for 2.95 and 2.96. Argh
Unbelievably, 3.1 doesn't remove empty loops either. I think there's a case for a compiler flag, `-fremove-empty-loops'.
Empty loop delays aren't portable acrosss compilers in general. If you _really_ want an empty loop that must always work with GCC, it's easy enough to write:
for (i = 0; i < 100000; i++) __asm__ __volatile__ ("");
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