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From Vince Weaver:
I've been running the SPEC CPU 2006 benchmarks under valgrind (doing some
work on my BBV generating plugin).
There are two benchmarks that have issues, and I thought I'd share them
here for future reference.
1). zeusmp - does not run
It has a 1GB data segment, which valgrind cannot handle on a 32-bit
2). dealII - runs forever, never ending
It took a while, but I tracked this down to a 64bit/80bit
floating point issue.
The code in the QGauss<1>::QGauss() function has some code like this:
const long double tolerance = std::max (static_cast<long double>
(std::numeric_limits<double>::epsilon() / 100),
static_cast<long double>(std::numeric_limits<long
double>::epsilon() *5));
do {
various fp operations
} while (abs(p1/pp) > tolerance);
The tolerance in this case is being set to ~2.22e-18, but the
abs(p1/pp) value never gets below ~2.586e-17 under valgrind.
[This is because Valgrind only uses 64-bit FP values on x86, not 80-bit
This is similar to an issue that happens with the "art"
benchmark on SPEC CPU 2000, but in the "art" case it only
makes the code take longer to finish; this "dealII" problem
makes the benchmark loop forever.