potential bug with compiler setting

[tj-sun]

It appears the following test passes with gcc but fails with icc
regression/test_helmholtz_sphere.py::test_helmholtz_sphere_lowestorder[MeshClass1]

[wence-]

fails in what way?

[tj-sun]

convergence rate

assert (l2conv > 1.7).all()
E assert <built-in method all of numpy.ndarray object at 0x7f88b791cd00>()
E + where <built-in method all of numpy.ndarray object at 0x7f88b791cd00> = array([ 0.04270851, 0.01346899]) > 1.7.all

[wence-]

OK, yes, that's bad.

[miklos1]

Is this a bug in the Intel compiler, TSFC, or COFFEE?

[tj-sun]

On first look it appears that 1) the c files are identical 2) the compilation commands are identical
So I guess it's probably problem with either the compiler (unlikely?) or that we ought to use different flags for different compilers somehow.

Will have another look later.

[miklos1]

Before saying that it's a C compiler bug, you must judge that the generated code is standard conforming and does not contain undefined behaviour.

Another thing to try with potential C compiler bugs is the change/lower the optimisation level.