[PATCH] D30254: Remove sometimes faulty rewrite of memcpy in instcombine.

[Mikael Holmén via Phabricator via llvm-commits]

uabelho added a comment.

Alright!

So I've done four runs of

lnt runtest nt --sandbox SANDBOX --cflag=-m32 --cc <path-to-compiler> --test-suite <path-to-test-suite>

Two (base 1 and base2) on two commits without the patch, where the only difference between the commits is
a white space in CODE_OWNERS.txt.

Then two runs (patch1 and patch2) on two other commits containing the patch, where the only difference
between the commits is the same white space change in CODE_OWNERS.txt

If I compare the two runs without the patch there are Execution Time regressions up to 98.36% and Compile
Time regressions up to 219.18%. A total of: "Performance Regressions 	191".

I did the above just to get an indication of how stable the numbers are when nothing significant at all has changed.

I have a hard time realizing if the patch changes anything significantly so I put up a couple of screen shots from
different comparisons from the web UI:
http://imgur.com/a/SVg08

There we have base2 vs base1 which is the two runs without the patch compared.

Then four pictures where the two patch runs are compared to the two base runs.

Can you make anything out of this?

(Btw, with --cflag=-m32 three tests seems to fail:

FAIL: MultiSource/Applications/ClamAV/clamscan.compile_time (1 of 2465)
FAIL: MultiSource/Applications/ClamAV/clamscan.execution_time (494 of 2465)
FAIL: MultiSource/Benchmarks/DOE-ProxyApps-C/XSBench/XSBench.execution_time (495 of 2465)

both with and without the patch. I don't see those FAILs without -m32.)


https://reviews.llvm.org/D30254