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author | Hans Wennborg <hans@hanshq.net> | 2019-09-27 09:54:26 +0000 |
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committer | Hans Wennborg <hans@hanshq.net> | 2019-09-27 09:54:26 +0000 |
commit | 3740ae3b8aeeb498243504148f666204f9856302 (patch) | |
tree | 94e3a927b111252cf7b7210b4e972e6c7379ebc9 /lldb/packages/Python/lldbsuite/test/python_api/module_section | |
parent | 4627bdedd90de9b5fb9115ac2ffae83f5ce9096e (diff) | |
download | bcm5719-llvm-3740ae3b8aeeb498243504148f666204f9856302.tar.gz bcm5719-llvm-3740ae3b8aeeb498243504148f666204f9856302.zip |
Revert r372893 "[CodeGen] Replace -max-jump-table-size with -max-jump-table-targets"
This caused severe compile-time regressions, see PR43455.
> Modern processors predict the targets of an indirect branch regardless of
> the size of any jump table used to glean its target address. Moreover,
> branch predictors typically use resources limited by the number of actual
> targets that occur at run time.
>
> This patch changes the semantics of the option `-max-jump-table-size` to limit
> the number of different targets instead of the number of entries in a jump
> table. Thus, it is now renamed to `-max-jump-table-targets`.
>
> Before, when `-max-jump-table-size` was specified, it could happen that
> cluster jump tables could have targets used repeatedly, but each one was
> counted and typically resulted in tables with the same number of entries.
> With this patch, when specifying `-max-jump-table-targets`, tables may have
> different lengths, since the number of unique targets is counted towards the
> limit, but the number of unique targets in tables is the same, but for the
> last one containing the balance of targets.
>
> Differential revision: https://reviews.llvm.org/D60295
llvm-svn: 373060
Diffstat (limited to 'lldb/packages/Python/lldbsuite/test/python_api/module_section')
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