Hi,
Please, reply and keep replying to [email protected], so that proceedings
are kept together.
> Probably this "strict aliasing" 64-bit optimization bug for
> "crypto/bn/bn_nist.c"
>
> Mac OSX compiler fail test/ectest: cc [Apple LLVM version 4.2
> (clang-425.0.24) (based on LLVM 3.2svn)] gcc-mp-4.3 gcc-mp-4.4 gcc-mp-4.5
> gcc-mp-4.6 clang-mp-3.0 clang-mp-3.1 clang-mp-3.2
>
> Mac OSX compiler test/ectest OK: gcc-apple-4.2 gcc-mp-4.7 gcc-mp-4.8
> [gcc-mp-4.8 (MacPorts gcc48 4.8-20130203_0+universal) 4.8.0 20130203
> (experimental)] clang-mp-2.9 clang-mp-3.3 [clang version 3.3 (trunk 173279)]
In other words it's at least obvious that it varies with compiler
version. One can argue about where the bug is, compiler or bn_nist.c,
but it's not matter of probability. Anyway as I can't reproduce the
problem you'd have to assist.
For reference. Why does it show up with no-asm? bn_nist.c is collection
of functions for specific moduli, but it's perfectly possible to
calculate the result using general-purpose subroutines. It was found
that general-purpose *assembly* code paths deliver better performance
and it was arranged so that bn_nist is not invoked in asm builds (look
for #if defined(OPENSSL_BN_ASM_MONT) in crypto/ec/ec_cvt.c).
> After patch:
Could you test following *instead*? In every #if defined(NIST_INT64)
section you'll see a number of references to bp[something]. Can you
replace them with buf.ui[samething] and run the test? Currently bp is
constified buf.ui and it might give overeager compiler idea to reorder
references to buf in #if defined(NIST_IN64) section and [inlined]
nist_cp_bn_0 and cause the mayhem.
> $ diff -u ../openssl-SNAP-20130212/crypto/bn/bn_nist.c crypto/bn/bn_nist.c
> --- ../openssl-SNAP-20130212/crypto/bn/bn_nist.c 2013-01-11
> 18:13:43.000000000 +0400
> +++ crypto/bn/bn_nist.c 2013-02-12 13:51:12.000000000 +0400
> @@ -421,7 +421,7 @@
>
> nist_cp_bn_0(buf.bn, a_d + BN_NIST_192_TOP, top - BN_NIST_192_TOP,
> BN_NIST_192_TOP);
>
> -#if defined(NIST_INT64)
> +#if defined(NIST_INT64) && (BN_BITS2!=64 || defined(NO_BUG_CLANG_GCC_64BIT))
> {
> NIST_INT64 acc; /* accumulator */
> unsigned int *rp=(unsigned int *)r_d;
> @@ -701,7 +701,7 @@
>
> nist_cp_bn_0(buf.bn, a_d + BN_NIST_256_TOP, top - BN_NIST_256_TOP,
> BN_NIST_256_TOP);
>
> -#if defined(NIST_INT64)
> +#if defined(NIST_INT64) && (BN_BITS2!=64 || defined(NO_BUG_CLANG_GCC_64BIT))
> {
> NIST_INT64 acc; /* accumulator */
> unsigned int *rp=(unsigned int *)r_d;
> @@ -906,7 +906,7 @@
>
> nist_cp_bn_0(buf.bn, a_d + BN_NIST_384_TOP, top - BN_NIST_384_TOP,
> BN_NIST_384_TOP);
>
> -#if defined(NIST_INT64)
> +#if defined(NIST_INT64) && (BN_BITS2!=64 || defined(NO_BUG_CLANG_GCC_64BIT))
> {
> NIST_INT64 acc; /* accumulator */
> unsigned int *rp=(unsigned int *)r_d;
>
>
> Mac OSX compiler fail test/ectest: gcc-mp-4.3 gcc-mp-4.4 gcc-mp-4.5 gcc-mp-4.6
>
> Mac OSX compiler test/ectest OK: cc [Apple LLVM version 4.2 (clang-425.0.24)
> (based on LLVM 3.2svn)] gcc-apple-4.2 gcc-mp-4.7 gcc-mp-4.8 [gcc-mp-4.8
> (MacPorts gcc48 4.8-20130203_0+universal) 4.8.0 20130203 (experimental)]
> clang-mp-2.9 clang-mp-3.0 clang-mp-3.1 clang-mp-3.2 clang-mp-3.3 [clang
> version 3.3 (trunk 173279)]
>
>
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