http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57996
Bug ID: 57996
Summary: Fold more standard complex functions
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: glisse at gcc dot gnu.org
Hello,
we don't seem to try any optimization on the cpow function (and many other
complex functions). In particular, if the arguments are complex_expr<x,0.>, we
don't take advantage of it.
Note that the C++ library has overloads for mixed pow calls and some code to
detect when operands are real, but that isn't the best place for it, ideally it
would just convert all to complex, call __builtin_cpow and let the middle-end
handle it. Related to PR libstdc++/56106.
Some of the optimizations should be limited to the unsafe-math case, but not
all (and the exact list may depend on whether your libc provides a correctly
rounded cpow or not).
cpow requires some special code, but the test for real arguments could be
shared by several unary functions (csin, ccos, cexp, ...).
