Replace std::deque with std::vector for Lengauer-Tarjan

[samolisov]

Issue: #383

[samolisov]

I use the following benchmark: dominator_tree_benchmark.cpp

On my machine (32 X 1792.7 MHz CPU s with hyper-threading and almost zero Load Average, Ubuntu 20.4) the report is the following (we may use it as a base-line:

Running ./dominator_tree_benchmark
Run on (64 X 1792.7 MHz CPU s)
CPU Caches:
  L1 Data 32 KiB (x32)
  L1 Instruction 32 KiB (x32)
  L2 Unified 512 KiB (x32)
  L3 Unified 16384 KiB (x8)
Load Average: 0.00, 0.01, 0.00
----------------------------------------------------------------------------------
Benchmark                                        Time             CPU   Iterations
----------------------------------------------------------------------------------
Tarjan's paper (vertex list)                  1545 ns         1545 ns       453859
Tarjan's paper  (vertex vector)               1519 ns         1519 ns       461328
Appel. fig. 19.8 (vertex list)                1587 ns         1587 ns       439286
Appel. fig. 19.8  (vertex vector)             1489 ns         1488 ns       473160
Muchnick. fig. 8.18 (vertex list)              870 ns          870 ns       805296
Muchnick. fig. 8.18  (vertex vector)           847 ns          847 ns       833885
Cytron's paper, fig. 9 (vertex list)          1812 ns         1812 ns       391492
Cytron's paper, fig. 9  (vertex vector)       1651 ns         1651 ns       421622
From a code, 186 BBs (vertex list)           22388 ns        22386 ns        29279
From a code, 186 BBs (vertex vector)         19391 ns        19389 ns        35854

After replacing std::deque with std::vector as it was suggested by @jeremy-murphy (commit ), the numbers are the following:

----------------------------------------------------------------------------------
Benchmark                                        Time             CPU   Iterations
----------------------------------------------------------------------------------
Tarjan's paper (vertex list)                   944 ns          944 ns       747521
Tarjan's paper  (vertex vector)                852 ns          852 ns       822843
Appel. fig. 19.8 (vertex list)                 956 ns          956 ns       729393
Appel. fig. 19.8  (vertex vector)              865 ns          865 ns       807835
Muchnick. fig. 8.18 (vertex list)              560 ns          560 ns      1252412
Muchnick. fig. 8.18  (vertex vector)           543 ns          543 ns      1306887
Cytron's paper, fig. 9 (vertex list)          1164 ns         1164 ns       602748
Cytron's paper, fig. 9  (vertex vector)       1054 ns         1054 ns       666930
From a code, 186 BBs (vertex list)           12750 ns        12749 ns        55535
From a code, 186 BBs (vertex vector)         11284 ns        11283 ns        62585

Here we can see about 40% speedup for the "large" cases (for CFGs with 186 basic blocks).