clang: fix nested loop unrolling #3016
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It turns out that nested loop unrolling makes the unrolling
transformation not to work in clang (at least for eBPF architecture):
./pkg/ebpf/c/common/common.h:83:5: warning: loop not unrolled: the
optimizer was unable to perform the requested transformation; the
transformation might be disabled or specified as part of an unsupported
transformation ordering [-Wpass-failed=transform-warning]
for (i = 0; i < n; prefix++, str++, i++) {
^
By having two "has_prefix" function versions, depending if the caller is
already unrolling the loop or not, clang is able to transform the loop
in multiple versions.
Fixes: #2624
rafaeldtinoco
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Vanilla 4.19 kernels (non CORE only) don't like this fix BUT they are going to be dropped with CORE only Tracee (#1651) so I'm closing this and will have this commit together with the non CORE drop. |
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It turns out that nested loop unrolling makes the unrolling transformation not to work in clang (at least for eBPF architecture):
./pkg/ebpf/c/common/common.h:83:5: warning: loop not unrolled: the optimizer was unable to perform the requested transformation; the transformation might be disabled or specified as part of an unsupported transformation ordering [-Wpass-failed=transform-warning]
By having two "has_prefix" function versions, depending if the caller is already unrolling the loop or not, clang is able to transform the loop in multiple versions.
Fixes: #2624