[AArch64] PR28877: Don't assume we're running after legalization when
creating vcvtfp2fxs
Summary:
The DAG combine transformation that was generating the
aarch64_neon_vcvtfp2fxs node was assuming that all inputs where legal
and wasn't accounting that the input could be a v4f64 if we're trying
to do the transformation before legalization. We now bail out in this
case.
All illegal types besides v4f64 were already rejected.
Fixes https://llvm.org/bugs/show_bug.cgi?id=28877
Reviewers: jmolloy
Subscribers: aemerson, rengolin, llvm-commits
Differential Revision: https://reviews.llvm.org/D23261
This fixes several ports on AArch64.
Requested by: andrew
MFC after: 3 days