#3717: Superfluous seq no eliminated
---------------------------------------------+------------------------------
Reporter: rl | Owner:
Type: bug | Status: closed
Priority: normal | Milestone: 7.0.2
Component: Compiler | Version: 6.13
Resolution: fixed | Keywords:
Testcase: simplCore/should_compile/T3717 | Blockedby:
Difficulty: | Os: Unknown/Multiple
Blocking: | Architecture: Unknown/Multiple
Failure: Runtime performance bug |
---------------------------------------------+------------------------------
Changes (by simonpj):
* status: new => closed
* resolution: => fixed
Comment:
Fixed by
{{{
Tue Jan 25 11:05:25 GMT 2011 [email protected]
* Fix Trac #3717 by making exprOkForSpeculation a bit cleverer
The main change here is to do with dropping redundant seqs.
See Note [exprOkForSpeculation: case expressions] in CoreUtils.
M ./compiler/coreSyn/CoreUtils.lhs -5 +14
M ./compiler/simplCore/Simplify.lhs -36 +47
Tue Jan 25 11:04:18 GMT 2011 [email protected]
* Improve dataToTag# magic
dataToTag# is a bit unsatisfactory because it requires
its argument to be evaluated, and we don't have a good
way to enforce that. This patch adds some comments, and
makes exprOkForSpeculation a bit less picky in the case
of dataToTag# (since the argument may, in fact, not be
eval'd).
M ./compiler/coreSyn/CorePrep.lhs -3 +8
M ./compiler/coreSyn/CoreUtils.lhs +24
}}}
No need to merge; putting this in 7.2 is fine.
Simon
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3717#comment:5>
GHC <http://www.haskell.org/ghc/>
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