https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115427
Bug ID: 115427
Summary: fallback for interclass mathfn bifs like isinf,
isfinite, isnormal
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: linkw at gcc dot gnu.org
Target Milestone: ---
This is filed as follow up for the discussion in [1].
The optabs for isfinite and isnormal would be landed soon, the documentation
allows the optab expansion to fail (as it doesn't mention it's not allowed to),
but with an artificial FAIL in the define_expand for these optabs, there are
two cases:
1) for isinf, it would result in a call to isinf, but in fact
fold_builtin_interclass_mathfn is able to fold them if there is no target
specific implementation.
2) for isfinite and isnormal, since there is no library call registered, it
would result in a call to __builtin_{isfinite, isnormal}, which is completely
wrong.
So following Richi's suggestion, this PR is to follow up the falling back way.
[1]
https://inbox.sourceware.org/gcc-patches/17c9ab5d-f1d4-9447-fccf-d9aa0ad56...@linux.ibm.com/
