#1261: optLevelFlags is not monotonic
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Reporter: Stefan O'Rear <[EMAIL PROTECTED]> | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 6.7
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: | Architecture: x86
Os: Linux |
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Changes (by Stefan O'Rear <[EMAIL PROTECTED]>):
* summary: 15x performance regression between HEAD and 6.6 =>
optLevelFlags is not monotonic
Comment:
By suggestion of Don Stewart, I tried again with -O2 (vs. -O3), and the
regression vanished. Nor is it a backfiring optimization, for -ddump-
simpl-stats (his idea again) shows -O3 does less in every way. It appears
from cursory examination of the driver that the option flags are decoded
in such a way that they are not monotonic, which is confusingly counter to
gcc etc tradition.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1261>
GHC <http://www.haskell.org/ghc/>
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