Many VTK test fail on arm64 Mac due to Clang's new default of -ffp-contract=on
Building VTK master on my Intel Mac results in only 1 test failure. But on arm64 Macs, there are about 15.
You can see details here: https://open.cdash.org/viewTest.php?onlyfailed&buildid=9564918
I debugged them, and found at least 2 were due to very tight numerical precision expectations, and created MRs:
I then had some deja vu, and remembered how Clang 14 changed to default to -ffp-contract=on and how this caused numerical differences in our own code, more so on arm64 than x86_64. So I tried building again with -ffp-model=strict and now 13 of 15 pass.
Since this is clang’s default now (on almost all platforms), what should we do about this?
Require -ffp-model=strict? Loosen the strictness of the tests?
Edited by David Gobbi