Possible ICE with ifort 17 and -xMIC-AVX512

[eric_n_]

Hello,

Please find below an issue (and reproducer) encountered by one of our development

team members.

Thanks,

Eric

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Encountered an ICE in ifort 17.0.1.132 Build 20161005 attempting to cross-compile AVX512 on a Xeon.

CPU: Intel(R) Xeon(R) CPU E5-2650 v2 @ 2.60GHz

OS: Linux K-li2 2.6.32-642.13.1.el6.centos.plus.x86_64 #1 SMP Thu Jan 12 11:45:05 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

Example code:

program main

  implicit none

  real(8) :: turb, baseterm, sw

  turb = 1.0_8

  sw = 1.0_8

  baseterm = turb * (-1.0_8)*1.0_8/sw + 1.0_8/sw 

end program

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Other info:

No error on versions:

15.3.187

16.0.109

16.2.181

16.3.210

17.0.098

_______________________________________________________

Log showing only certain flag combos trigger the ICE:

user@K-li2% ifort -std03 -xMIC-AVX512 -O2 -fpe0 -c -o turb_spalart_mod.o turb_spalart_mod.f90

catastrophic error: **Internal compiler error: segmentation violation signal raised** Please report this error along with the circumstances in which it occurred in a Software Problem Report.  Note: File and line given may not be explicit cause of this error.

compilation aborted for turb_spalart_mod.f90 (code 1)

user@K-li2% ifort -std03 -xMIC-AVX512 -O2 -fpe1 -c -o turb_spalart_mod.o turb_spalart_mod.f90

[no error]

user@K-li2% ifort -std03 -xMIC-AVX512 -O2 -fpe0 -fp-model strict -c -o turb_spalart_mod.o turb_spalart_mod.f90

[no error]

user@K-li2% ifort -std03 -xMIC-AVX512 -O2 -fpe0 -fp-model precise -fp-model except -c -o turb_spalart_mod.o turb_spalart_mod.f90

010101_14277

catastrophic error: **Internal compiler error: internal abort** Please report this error along with the circumstances in which it occurred in a Software Problem Report.  Note: File and line given may not be explicit cause of this error.

compilation aborted for turb_spalart_mod.f90 (code 1)

_______________________________________________________

Avoided the error with the following tweak:

  baseterm = 1.0_8/sw - turb*1.0_8/sw

[Martyn_C_Intel]

Hi Eric,

     I believe the error may be occurring during constant folding (constant evaluation) during compilation - that's why changing how the expression is evaluated works around. I'm not sure why -fpe0 triggers it. The good news is that this problem no longer occurs with the version 17.0.2 (2017 update 2) compiler that was posted to the Intel Registration Center last week. Please try that compiler on your larger application, and let us know if there are still any problems.