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Fix Issue 16264(+11599) - BigInt multiplication crashes on 64-bit #5715

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merged 1 commit into from
Oct 28, 2017
Merged

Fix Issue 16264(+11599) - BigInt multiplication crashes on 64-bit #5715

merged 1 commit into from
Oct 28, 2017

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yosupo06
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@yosupo06 yosupo06 commented Aug 31, 2017 •
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Thanks for your pull request, @yosupo06! We are looking forward to reviewing it, and you should be hearing from a maintainer soon.

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✓ 16264 BigInt multiplication crashes on 64-bit (biguintnoasm.d(276): Range violation)

@MartinNowak
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Thanks for your fix and thorough testing.
A small explanation of what you fixed (in the commit message) would be really helpful to review this.

MartinNowak
MartinNowak reviewed Oct 15, 2017
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std/internal/math/biguintcore.d
mulKaratsuba(result[0 .. half + y.length], y, x[0 .. half], scratchbuff);
partial[] = result[half .. half + y.length];
mulKaratsuba(result[half .. $], y, x[half .. $], scratchbuff);
addAssignSimple(result[half .. half + y.length], partial);
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This looks structurally very similar to the variant below, any chance this could be integrated there?

std/internal/math/biguintcore.d
paddingY = true;
assert(chunksize + extra + chunksize *(numchunks-1) == x.length );
bool isExtraSmall = extra * extra * 2 < y.length * y.length;
if (numchunks == 1 && isExtraSmall)
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Maybe a comment what this condition means?

@MartinNowak
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thx

@MartinNowak MartinNowak merged commit 18c19d8 into dlang:stable Oct 28, 2017
@CyberShadow
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This pull request introduced a regression:
https://issues.dlang.org/show_bug.cgi?id=19740

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@MartinNowak MartinNowak MartinNowak approved these changes

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@yosupo06 @dlang-bot @MartinNowak @CyberShadow @JackStouffer