On 3/7/18 1:57 PM, Matt Gamble wrote:
This is a record for me with two 32bit vs 64bit issues in one day. Seems to be a problem with using "each" under 32bit which can be fixed by using foreach or switching to x64. Am I doing something wrong or is this the second bug I've found today?


Below is a silly case, that replicates an error. (i.e. I know I could use iota(0,9,2).array), but that does not demonstrate the potential bug and would not fix my actual program.)

import std.range;
import std.algorithm;
import std.stdio;

unittest
{
     auto a = new double[9];
     a[0] = 0;
     iota(1,a.length).each!(i => a[i] = a[i-1] + 2);
     writeln(a);
}

//x86, wrong, error
//[-nan, 2, 4, 6, 8, 10, 12, 14, 16]
//First-chance exception: std.format.FormatException Unterminated format specifier: "%" at C:\D\dmd2\windows\bin\..\..\src\phobos\std\format.d(1175)

//x64, correct
//[0, 2, 4, 6, 8, 10, 12, 14, 16]

unittest
{
     auto a = new double[9];
     a[0] = 0;
     foreach(i; 1..a.length) a[i] = a[i - 1] + 2;
     writeln(a);
}

//x86, correct
//[0, 2, 4, 6, 8, 10, 12, 14, 16]

//x64, correct
//[0, 2, 4, 6, 8, 10, 12, 14, 16]

This is windows 10, DMD v2.076.1


It has something to do with the fact that you are returning the value:

iota(1, a.length).each!((i) {a[i] = a[i - 1] + 2;}); // ok
iota(1, a.length).each!((i) {return a[i] = a[i - 1] + 2;}); // shows error


Which is odd to say the least, I don't think each is supposed to do anything with the return value.

I don't get the exception BTW (2.078.1 Windows 10).

Looking at each, it looks like it does this:

cast(void) unaryFun!pred(r.front);

So I tried this:

auto pred = i => a[i] = a[i-1] + 2;
foreach(i; 1 .. a.length)
   cast(void)pred(i);

And I see the -nan value. Remove the cast(void) and I don't see it.

Clearly there is some codegen issue here.

-Steve

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