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[Bug regression/71231] [7 Regression]: 300% runtime increase for rnflow
- From: "pinskia at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 24 May 2016 00:17:32 +0000
- Subject: [Bug regression/71231] [7 Regression]: 300% runtime increase for rnflow
- Auto-submitted: auto-generated
- References: <bug-71231-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71231
--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This code has the following warning:
!CRAY - The following multiply must be done with 64 bits (not 46 bits)
! The algoritm depends on the overflow characteristics of
! a 32 or 64 bit multiply.
So the code is implicitly saying it needs to be done using overflow as wrapping
for signed integer but in Fortran, overflow is undefined.
This is the code from genuni.