[commit: ghc] master: Optimize self-recursive tail calls (d61c3ac)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/d61c3ac186c94021c851f7a2a6d20631e35fc1ba/ghc

>---------------------------------------------------------------

commit d61c3ac186c94021c851f7a2a6d20631e35fc1ba
Author: Jan Stolarek <jan.stolarek at p.lodz.pl>
Date:   Thu Aug 29 10:57:04 2013 +0100

    Optimize self-recursive tail calls
    
    This patch implements loopification optimization. It was described
    in "Low-level code optimisations in the Glasgow Haskell Compiler" by
    Krzysztof Woś, but we use a different approach here. Krzysztof's
    approach was to perform optimization as a Cmm-to-Cmm pass. Our
    approach is to generate properly optimized tail calls in the code
    generator, which saves us the trouble of processing Cmm. This idea
    was proposed by Simon Marlow. Implementation details are explained
    in Note [Self-recursive tail calls].
    
    Performance of most nofib benchmarks is not affected. There are
    some benchmarks that show 5-7% improvement, with an average improvement
    of 2.6%. It would require some further investigation to check if this
    is related to benchamrking noise or does this optimization really
    help make some class of programs faster.
    
    As a minor cleanup, this patch renames forkProc to forkLneBody.
    It also moves some data declarations from StgCmmMonad to
    StgCmmClosure, because they are needed there and it seems that
    StgCmmClosure is on top of the whole StgCmm* hierarchy.


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d61c3ac186c94021c851f7a2a6d20631e35fc1ba
 compiler/codeGen/StgCmmBind.hs    |   16 +++++-
 compiler/codeGen/StgCmmClosure.hs |  110 ++++++++++++++++++++++++++-----------
 compiler/codeGen/StgCmmExpr.hs    |  104 ++++++++++++++++++++++++++++++-----
 compiler/codeGen/StgCmmMonad.hs   |   86 ++++++++++++++---------------
 4 files changed, 222 insertions(+), 94 deletions(-)

Diff suppressed because of size. To see it, use:

    git diff-tree --root --patch-with-stat --no-color --find-copies-harder --ignore-space-at-eol --cc d61c3ac186c94021c851f7a2a6d20631e35fc1ba