[LLVMdev] JIT compilation 2-3 times slower in latest LLVM snapshot

[Dibyendu Majumdar]

On 11 July 2015 at 13:16, Dibyendu Majumdar <mobile at majumdar.org.uk> wrote:
> On 11 July 2015 at 13:14, Caldarale, Charles R
> <Chuck.Caldarale at unisys.com> wrote:
>>> From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu]
>>> On Behalf Of Dibyendu Majumdar
>>> Subject: [LLVMdev] JIT compilation 2-3 times slower in latest LLVM snapshot
>>
>>> I updated my clone of the LLVM github mirror today and I am finding
>>> that the JIT compilation is now 2-3 times slower. The last time I
>>> refreshed was maybe 2 weeks ago. Is there a known change that would
>>> explain this?
>>
>> Debug+Asserts build rather than Release (or Release+Asserts)?
>>
>
> I haven't changed my build - it is a Release build. Have the settings
> in the Released build has changed recently?
>

Just to be sure I completely rebuilt LLVM (below are some snippets
from the build):

C:\github\llvm\build>cmake -DCMAKE_INSTALL_PREFIX=c:\LLVM37
-DCMAKE_BUILD_TYPE=Release -DLLVM_TARGETS_TO_BUILD="X86" -G "Visual
Studio 14 Win64" ..
-- Target triple: x86_64-pc-win32
-- Native target architecture is X86
-- Threads enabled.
-- Doxygen disabled.
-- Sphinx disabled.
-- Go bindings disabled.
-- Could NOT find OCaml (missing:  OCAMLFIND OCAML_VERSION OCAML_STDLIB_PATH)
-- OCaml bindings disabled.
-- Using Debug VC++ CRT: MDd
-- Using Release VC++ CRT: MD
-- Using MinSizeRel VC++ CRT: MD
-- Using RelWithDebInfo VC++ CRT: MD
-- Using Release VC++ CRT: MD
-- Constructing LLVMBuild project information
-- LLVMHello ignored -- Loadable modules not supported on this platform.
-- Targeting X86
-- BugpointPasses ignored -- Loadable modules not supported on this platform.
-- Configuring done
-- Generating done
-- Build files have been written to: C:/github/llvm/build


Visual Studio output:

140>Project not selected to build for this solution configuration
141>------ Skipped Build: Project: check-all, Configuration: Release x64 ------
141>Project not selected to build for this solution configuration
142>------ Skipped Build: Project: check, Configuration: Release x64 ------
142>Project not selected to build for this solution configuration
========== Build: 136 succeeded, 0 failed, 0 up-to-date, 6 skipped ==========

and

1>------ Build started: Project: LTO_exports, Configuration: Release x64 ------
2>------ Build started: Project: intrinsics_gen, Configuration:
Release x64 ------
3>------ Build started: Project: LibOptionsTableGen, Configuration:
Release x64 ------
4>------ Build started: Project: X86CommonTableGen, Configuration:
Release x64 ------
5>------ Build started: Project: llvm-ranlib, Configuration: Release x64 ------
6>------ Build started: Project: llvm-lib, Configuration: Release x64 ------
7>------ Build started: Project: INSTALL, Configuration: Release x64 ------
7>  -- Install configuration: "Release"


Same issue.