Bug 31301 - Extremely long compilation time
Summary: Extremely long compilation time
Status: RESOLVED DUPLICATE of bug 20923
Alias: None
Product: gcc
Classification: Unclassified
Component: fortran (show other bugs)
Version: 4.3.0
: P3 normal
Target Milestone: ---
Assignee: Not yet assigned to anyone
URL:
Keywords: compile-time-hog
Depends on:
Blocks:
 
Reported: 2007-03-21 19:53 UTC by Tobias Burnus
Modified: 2009-12-10 08:26 UTC (History)
3 users (show)

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Description Tobias Burnus 2007-03-21 19:53:06 UTC 
The following program compiles with g95 and f95 in less than a second. gfortran needs more than several minutes (until I lost patience).

I think gfortran does not enter an endless loop but tries to solve the h1 assignment explicitly. (At least is seems to do this with a much stripped down version.)

Full example:
http://home.comcast.net/~kmbtib/fft64t.i90
http://home.comcast.net/~kmbtib/fft64t.f90

The slow-down line is:
  h1 = (/(sum((/(exp(-2*pi*(0,1)*mod(k*L,N)/N)*h2(L),L=0,N-1)/)),k=0,N-1)/)
Comment 1 Andrew Pinski 2007-03-21 21:45:18 UTC 
I bet this is a duplicate of another bug like say PR 20923.
Comment 2 Tobias Burnus 2007-03-21 21:56:05 UTC 

*** This bug has been marked as a duplicate of 20923 ***
Comment 3 Tobias Burnus 2009-12-10 08:26:25 UTC 
Actually a duplicate of PR 32489 (or rather the other way round).

Same test case, same reporter; this one is 3 months older - but the other PR has a patch ...