Commit Graph

8 Commits

Author SHA1 Message Date
David Sehr
6c4265a541 The current X86 NOP padding uses one long NOP followed by the remainder in
one-byte NOPs.  If the processor actually executes those NOPs, as it sometimes
does with aligned bundling, this can have a performance impact.  From my
micro-benchmarks run on my one machine, a 15-byte NOP followed by twelve
one-byte NOPs is about 20% worse than a 15 followed by a 12.  This patch
changes NOP emission to emit as many 15-byte (the maximum) as possible followed
by at most one shorter NOP.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176464 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-05 00:02:23 +00:00
Derek Schuff
f918d7fd73 [MC] Bundle alignment: Invalidate relaxed fragments
Currently, when a fragment is relaxed, its size is modified, but its
offset is not (it gets laid out as a side effect of checking whether
it needs relaxation), then all subsequent fragments are invalidated
because their offsets need to change. When bundling is enabled,
relaxed fragments need to get laid out again, because the increase in
size may push it over a bundle boundary. So instead of only
invalidating subsequent fragments, also invalidate the fragment that
gets relaxed, which causes it to get laid out again.

This patch also fixes some trailing whitespace and fixes the
bundling-related debug output of MCFragments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174401 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-05 17:55:27 +00:00
Derek Schuff
b11917c1aa [MC] bundle alignment: prevent padding instructions from crossing bundle boundaries
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174067 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-31 17:00:03 +00:00
Eli Bendersky
59d152197d Add some additional tests for the .bundle_lock align_to_end feature that didn't
make into the last commit.

Also, update the test-generation script to generate an exhaustive test for
align_to_end as well, and include the generated test.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171811 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-07 23:12:59 +00:00
Eli Bendersky
6c1d4972cf Add the align_to_end option to .bundle_lock in the MC implementation of aligned
bundling. The document describing this feature and the implementation has also
been updated:

https://sites.google.com/a/chromium.org/dev/nativeclient/pnacl/aligned-bundling-support-in-llvm


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171797 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-07 21:51:08 +00:00
Eli Bendersky
15019a8814 Change Lit error redirection to FileCheck to a more common syntax since it
can potentially cause some bots to fail.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170726 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-20 19:54:02 +00:00
Eli Bendersky
b17201f1b8 Add a largish auto-generated test for the aligned bundling feature, along with
the script generating it. The test should never be modified manually. If anyone
needs to change it, please change the script and re-run it.

The script is placed into utils/testgen - I couldn't think of a better place,
and after some discussion on IRC this looked like a logical location.





git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170720 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-20 19:16:57 +00:00
Eli Bendersky
16996c4940 Tests for the aligned bundling support added in r170718
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170719 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-20 19:07:30 +00:00