[SelectionDAG] Allow sin/cos -> sincos optimization on GNU triples w/ just -fno-math-errno
Summary:
This change enables the sin(x) cos(x) -> sincos(x) optimization on GNU
target triples. This optimization was being inhibited when -ffast-math
wasn't set because sincos in GLibC does not set errno, while sin and cos
do. However, this optimization will only run if the attributes on the
sin/cos calls include readnone, which is how clang represents the fact
that it doesn't care about the errno values set by these functions (via
the -fno-math-errno flag).
Reviewers: hfinkel, bogner
Subscribers: mcrosier, javed.absar, llvm-commits, paul.redmond
Differential Revision: https://reviews.llvm.org/D32921
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305204 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed