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digitalmars.D.learn - Internal Compiler Error Help

reply "Saurabh Das" <saurabh.das gmail.com> writes:
Hello,

We have been working on a genetic programming project, and 
occasionally the compiler fails and gives an internal error. I've 
captured and reduced one of these down to a single expression. 
See http://dpaste.dzfl.pl/e7a66aa067ab (reduced_expr.d)

When I compile this file using: dmd -c -O reduced_expr.d

It says:
DMD 2.066.1] Internal error: backend/cod1.c 1562
DMD 2.067.1] Internal error: backend/cod1.c 1567

The compile succeeds without the '-O' flag.

Am I correct in assuming that an internal error in the compiler 
should be filed as a bug report?

As you can see, the expression is a massive ugly thing, as is 
often the case with genetic programming. I'd like to reduce this 
expression further before filing said bug report. I recall seeing 
a project on this forum which automatically figures out the 
simplest program which causes a compile failure. Can someone 
kindly point me to it?

Thanks,
Saurabh
May 21 2015
next sibling parent reply "Andrea Fontana" <nospam example.com> writes:
https://github.com/CyberShadow/DustMite/wiki

On Thursday, 21 May 2015 at 08:28:30 UTC, Saurabh Das wrote:

 Hello,

 We have been working on a genetic programming project, and 
 occasionally the compiler fails and gives an internal error. 
 I've captured and reduced one of these down to a single 
 expression. See http://dpaste.dzfl.pl/e7a66aa067ab 
 (reduced_expr.d)

 When I compile this file using: dmd -c -O reduced_expr.d

 It says:
 DMD 2.066.1] Internal error: backend/cod1.c 1562
 DMD 2.067.1] Internal error: backend/cod1.c 1567

 The compile succeeds without the '-O' flag.

 Am I correct in assuming that an internal error in the compiler 
 should be filed as a bug report?

 As you can see, the expression is a massive ugly thing, as is 
 often the case with genetic programming. I'd like to reduce 
 this expression further before filing said bug report. I recall 
 seeing a project on this forum which automatically figures out 
 the simplest program which causes a compile failure. Can 
 someone kindly point me to it?

 Thanks,
 Saurabh
May 21 2015
parent reply "Saurabh Das" <saurabh.das gmail.com> writes:
Thanks!

Wow, dustmite is really useful. It reduces the expression down to:

double someFunction(double AvgPriceChangeNormalized, double 
TicksTenMinutesNormalized)
{
     return 
(TicksTenMinutesNormalized?1:AvgPriceChangeNormalized)?1:TicksTenMinutesNormalized/(TicksTenMinutesNormalized==0)==0;
}

Which gives a compiler error: Internal error: backend/cod1.c 1562
May 21 2015
parent reply "John Colvin" <john.loughran.colvin gmail.com> writes:
On Thursday, 21 May 2015 at 08:55:45 UTC, Saurabh Das wrote:

 Thanks!

 Wow, dustmite is really useful. It reduces the expression down 
 to:

 double someFunction(double AvgPriceChangeNormalized, double 
 TicksTenMinutesNormalized)
 {
     return 
 (TicksTenMinutesNormalized?1:AvgPriceChangeNormalized)?1:TicksTenMinutesNormalized/(TicksTenMinutesNormalized==0)==0;
 }

 Which gives a compiler error: Internal error: backend/cod1.c 
 1562


make that

double foo(double a, double b)
{
     return (b ? 1 : a) ? 1 : b / (b == 0) == 0;
}

and please submit to https://issues.dlang.org

That expression is, not to put too fine a point on it, mad. The 
operator precedence itself is giving me a headache, let alone the 
division of a double by a boolean... I'm pretty sure it doesn't 
do what you want it to, unless what you want is seriously weird.

As a matter of fact, i'm pretty sure that expression evaluates to 
1, irrelevant of the values of the two variables.
May 21 2015
next sibling parent reply "John Colvin" <john.loughran.colvin gmail.com> writes:
On Thursday, 21 May 2015 at 10:24:59 UTC, John Colvin wrote:

 On Thursday, 21 May 2015 at 08:55:45 UTC, Saurabh Das wrote:

 Thanks!

 Wow, dustmite is really useful. It reduces the expression down 
 to:

 double someFunction(double AvgPriceChangeNormalized, double 
 TicksTenMinutesNormalized)
 {
    return 
 (TicksTenMinutesNormalized?1:AvgPriceChangeNormalized)?1:TicksTenMinutesNormalized/(TicksTenMinutesNormalized==0)==0;
 }

 Which gives a compiler error: Internal error: backend/cod1.c 
 1562


 make that

 double foo(double a, double b)
 {
     return (b ? 1 : a) ? 1 : b / (b == 0) == 0;
 }

 and please submit to https://issues.dlang.org

 That expression is, not to put too fine a point on it, mad. The 
 operator precedence itself is giving me a headache, let alone 
 the division of a double by a boolean... I'm pretty sure it 
 doesn't do what you want it to, unless what you want is 
 seriously weird.

 As a matter of fact, i'm pretty sure that expression evaluates 
 to 1, irrelevant of the values of the two variables.


s/irrelevant/irrespective/
May 21 2015
parent reply "Saurabh Das" <saurabh.das gmail.com> writes:
 and please submit to https://issues.dlang.org




Submitted: https://issues.dlang.org/show_bug.cgi?id=14613


 That expression is, not to put too fine a point on it, mad. 
 The operator precedence itself is giving me a headache, let 
 alone the division of a double by a boolean... I'm pretty sure 
 it doesn't do what you want it to, unless what you want is 
 seriously weird.

 As a matter of fact, i'm pretty sure that expression evaluates 
 to 1, irrelevant of the values of the two variables.


 s/irrelevant/irrespective/


The original expression was a candidate in a genetic programming 
population - a result of trial and error / "natural" selection 
over a few generations. The dustmite-reduced expression is really 
weird I agree - I don't know what to make of it. I've reported it 
as I found it.

The otiginal expression is not so wierd, it just haphazardly 
long. It doesn't do any strange divides or compares.

In either case, it shouldn't compile normally without the '-O' 
and fail to compile with it.

We managed a 1000x speed up over Java on our genetic programming 
system by using D, but this compile failure is preventing us from 
using the release / optimised builds :((

Thanks,
Saurabh
May 21 2015
parent reply "Saurabh Das" <saurabh.das gmail.com> writes:
PS: The original expression: 
http://dpaste.dzfl.pl/raw/e7a66aa067ab

double someFunction(double AvgPriceChangeNormalized, double 
DayFactor, double TicksTenMinutesNormalized)
{
     return 
((((AvgPriceChangeNormalized)*(0.0868))*((DayFactor)*(TicksTenMinutesNormalized)))*(((AvgPriceChangeNormalized)*(0.0868))*(((((((((TicksTenMinutesNormalized)==0)?(1):((AvgPriceChangeNormalized)/(TicksTenMinutesNormalized)))-((TicksTenMinutesNormalized)+(DayFactor)))==0)?(1):((TicksTenMinutesNormalized)/((((TicksTenMinutesNormalized)==0)?(1):((AvgPriceChangeNormalized)/(TicksTenMinutesNormalized)))-((TicksTenMinutesNormalized)+(DayFactor)))))==0)?(1):(((TicksTenMinutesNormalized)+(-0.865))/((((((TicksTenMinutesNormalized)==0)?(1):((AvgPriceChangeNormalized)/(TicksTenMinutesNormalized)))-((TicksTenMinutesNormalized)+(DayFactor)))==0)?(1):((TicksTenMinutesNormalized)/((((TicksTenMinutesNormalized)==0)?(1):((AvgPriceChangeNormalized)/(TicksTenMinutesNormalized)))-((TicksTenMinutesNormalized)+(DayFactor)))))))*(TicksTenMinutesNormalized))));
}
May 21 2015
next sibling parent ketmar <ketmar ketmar.no-ip.org> writes:
On Thu, 21 May 2015 11:36:14 +0000, Saurabh Das wrote:


 PS: The original expression:
 http://dpaste.dzfl.pl/raw/e7a66aa067ab
=20
 double someFunction(double AvgPriceChangeNormalized, double DayFactor,
 double TicksTenMinutesNormalized)
 {
      return
 ((((AvgPriceChangeNormalized)*(0.0868))*((DayFactor)*


(TicksTenMinutesNormalized)))*(((AvgPriceChangeNormalized)*(0.0868))*
(((((((((TicksTenMinutesNormalized)=3D=3D0)?(1):((AvgPriceChangeNormalized)=
/
(TicksTenMinutesNormalized)))-((TicksTenMinutesNormalized)
+(DayFactor)))=3D=3D0)?(1):((TicksTenMinutesNormalized)/
((((TicksTenMinutesNormalized)=3D=3D0)?(1):((AvgPriceChangeNormalized)/
(TicksTenMinutesNormalized)))-((TicksTenMinutesNormalized)
+(DayFactor)))))=3D=3D0)?(1):(((TicksTenMinutesNormalized)+(-0.865))/
((((((TicksTenMinutesNormalized)=3D=3D0)?(1):((AvgPriceChangeNormalized)/
(TicksTenMinutesNormalized)))-((TicksTenMinutesNormalized)
+(DayFactor)))=3D=3D0)?(1):((TicksTenMinutesNormalized)/
((((TicksTenMinutesNormalized)=3D=3D0)?(1):((AvgPriceChangeNormalized)/
(TicksTenMinutesNormalized)))-((TicksTenMinutesNormalized)
+(DayFactor)))))))*(TicksTenMinutesNormalized))));

 }


now i have to find a way to unsee it...=
May 21 2015
prev sibling parent reply "John Colvin" <john.loughran.colvin gmail.com> writes:
On Thursday, 21 May 2015 at 11:36:15 UTC, Saurabh Das wrote:

 PS: The original expression: 
 http://dpaste.dzfl.pl/raw/e7a66aa067ab

 double someFunction(double AvgPriceChangeNormalized, double 
 DayFactor, double TicksTenMinutesNormalized)
 {
     return 
 ((((AvgPriceChangeNormalized)*(0.0868))*((DayFactor)*(TicksTenMinutesNormalized)))*(((AvgPriceChangeNormalized)*(0.0868))*(((((((((TicksTenMinutesNormalized)==0)?(1):((AvgPriceChangeNormalized)/(TicksTenMinutesNormalized)))-((TicksTenMinutesNormalized)+(DayFactor)))==0)?(1):((TicksTenMinutesNormalized)/((((TicksTenMinutesNormalized)==0)?(1):((AvgPriceChangeNormalized)/(TicksTenMinutesNormalized)))-((TicksTenMinutesNormalized)+(DayFactor)))))==0)?(1):(((TicksTenMinutesNormalized)+(-0.865))/((((((TicksTenMinutesNormalized)==0)?(1):((AvgPriceChangeNormalized)/(TicksTenMinutesNormalized)))-((TicksTenMinutesNormalized)+(DayFactor)))==0)?(1):((TicksTenMinutesNormalized)/((((TicksTenMinutesNormalized)==0)?(1):((AvgPriceChangeNormalized)/(TicksTenMinutesNormalized)))-((TicksTenMinutesNormalized)+(DayFactor)))))))*(TicksTenMinutesNormalized))));
 }


fair enough. I thought normally you'd want to have some sort of 
expression simplification in genetic programming, to avoid adding 
too many superfluous degrees of freedom? Aside from the obvious 
problems, those extra degrees of freedom can put you at risk of 
overfitting.
May 21 2015
parent reply "Saurabh Das" <saurabh.das gmail.com> writes:
 fair enough. I thought normally you'd want to have some sort of 
 expression simplification in genetic programming, to avoid 
 adding too many superfluous degrees of freedom? Aside from the 
 obvious problems, those extra degrees of freedom can put you at 
 risk of overfitting.


Yes - our evaluation criteria gives bonus points for simpler 
expressions. We also strongly constrain the degrees of freedom. 
Both these aim to reduce overfitting. The expression seems rather 
complex because every division is protected by a equal to 0 
check. Since our data sets are vast and number of features is 
kept low, overfitting is less of a concern. We do watch out for 
it though.

In release builds, the compiler does the job of simplifying the 
expression, so we don't input a simplified expression a-priori. 
We are currently building this framework because earlier Java 
frameworks were deficient in speed. Already we have achieved a ~ 
1000x speedup, so right now we are looking to consolidate and 
stabilise. In the next iteration, we could think of adding a 
simplify expression feature.

Thanks,
Saurabh
May 21 2015
parent reply "Kagamin" <spam here.lot> writes:
If you're looking for speed, how about ldc?
May 21 2015
parent "Saurabh Das" <saurabh.das gmail.com> writes:
On Thursday, 21 May 2015 at 14:12:25 UTC, Kagamin wrote:

 If you're looking for speed, how about ldc?


Absolutely - we are working on getting it to compile on ldc 
and/or gdc.
May 21 2015
prev sibling parent "Kagamin" <spam here.lot> writes:
double foo(double b)
{
     return b / (b == 0) == 0;
}

Looks like this fails too.
May 21 2015
prev sibling parent Jonathan M Davis via Digitalmars-d-learn writes:
On Thursday, May 21, 2015 08:28:29 Saurabh Das via Digitalmars-d-learn wrote:

 Am I correct in assuming that an internal error in the compiler
 should be filed as a bug report?


Yes. You should never see an ICE, and the compiler should never segfault.
So, whenever you see either of those happen, please report it.

- Jonathan M Davis
May 21 2015