[PATCH] D13516: Fix overlapping replacements in clang-tidy.

[Angel Garcia via cfe-commits]

angelgarcia added a comment.

I've done a couple of runs for each version, and these are the results (I
have clang-tidy compiled with the option "RelWithDebInfo"):

$ time clang-tidy -checks=* test.cpp -- -std=c++11

Without looking for overlaps.

Suppressed 23463 warnings (23463 in non-user code).
Use -header-filter=.* to display errors from all non-system headers.

real    2m14.572s
user    2m13.136s
sys     0m0.483s

real    2m15.103s
user    2m13.361s
sys     0m0.687s

Bounding boxes

Suppressed 23463 warnings (23463 in non-user code).
Use -header-filter=.* to display errors from all non-system headers.

real    2m14.208s
user    2m13.051s
sys     0m0.643s

real    2m16.368s
user    2m14.286s
sys     0m0.986s

Quadratic

Suppressed 23463 warnings (23463 in non-user code).
Use -header-filter=.* to display errors from all non-system headers.

real    2m15.130s
user    2m13.627s
sys     0m0.499s

real    2m15.322s
user    2m13.660s
sys     0m0.683s

The time is about the same for all three versions. Note that the first
version doesn't do any sweep at all, and the last version invariably does
(23463 choose 2) = 275244453 sweeps. The amount of time required to do this
seems to be too low compared to the time that clang-tidy takes to output
these diagnostics.
Also, the fact that all three versions take about the same time is a bit
suspicious, but I double-checked that I was doing it right (I did a small
file with would cause overlapping and I checked if the message "note: this
fix will not be applied because it overlaps with another fix" was there
before each run).

I intended to implement Daniel's idea to check out which one was more
efficient, but with these results in sight I don't think it is worth it.


http://reviews.llvm.org/D13516