Bug #8847: opt_regexpmatch2 does not use method caching

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.1.0dev (2013-08-31 trunk 42741) [x86_64-darwin12.4.0]
• Backport: 1.9.3: UNKNOWN, 2.0.0: DONTNEED

The opt_regexpmatch2 instruction does not use method caching, instead it uses rb_funcall internally.

opt_regexpmatch2 is emitted by the compiler when a literal regexp is on the right hand side of the =~ operator.

This means a full method lookup must be performed every time the receiver of the =~ method call is not a String.

• Status changed from Open to Closed
• % Done changed from 0 to 100

This issue was solved with changeset r42742.
Charlie, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

---

• compile.c (NODE_MATCH3): pass CALL_INFO to opt_regexpmatch2

• insns.def (opt_regexpmatch2): use CALL_SIMPLE_METHOD to call =~ if
  the receiver is not a T_STRING [Bug #8847] [ruby-core:56916]

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 1.9.3: UNKNOWN, 2.0.0: UNKNOWN to 1.9.3: UNKNOWN, 2.0.0: REQUIRED

Hello, charlisome.

I think this fix should be backported to ruby_2_0_0.
Could you give me a testcase to cover this fix?
I'd like to confirm the same problem exists in ruby_2_0_0 branch.

nagachika: There's no incorrect behaviour that r42742 fixes - it is merely a performance improvement.

You can use the following benchmark script as a test:

require "benchmark"

puts Benchmark.measure {
  1_000_000.times do
    1 =~ //
    1 =~ //
    1 =~ //
    1 =~ //
    1 =~ //
    1 =~ //
    1 =~ //
    1 =~ //
  end
}

Before my commit, I get this result:

  0.330000   0.000000   0.330000 (  0.332941)

After my commit, I get:

  0.240000   0.000000   0.240000 (  0.241248)

You can probably do something similar to verify your backport is correct.

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 1.9.3: UNKNOWN, 2.0.0: REQUIRED to 1.9.3: UNKNOWN, 2.0.0: DONTNEED

Ah! I was misunderstanding that this is a bug fix.
Sorry for bother you.