If we don't, values that aren't precisely representable in f16 could
be used as-is in a promoted f32 operation, which would produce
incorrect results.
AArch64 had the correct behavior; add a focused test.
Fixes http://llvm.org/PR26871
llvm-svn: 268700
Summary:
Some target lowerings of FP_TO_FP16, for instance ARM's vcvtb.f16.f32
instruction, do not guarantee that the top 16 bits are zeroed out.
Remove the unsafe AssertZext and add tests to exercise this.
Reviewers: jmolloy, sbaranga, kristof.beyls, aadg
Subscribers: llvm-commits, srhines, aemerson
Differential Revision: http://reviews.llvm.org/D18426
llvm-svn: 264285
Summary:
During legalization if i16, do not ASSERTZEXT the result of FP_TO_FP16.
Directly return an FP_TO_FP16 node with return type as the
promote-to-type of i16.
This patch also removes extraneous length check. This legalization
should be valid even if integer and float types are of different
lengths.
This patch breaks a hard-float test for fp16 args. The test is changed
to allow a vmov to zero-out the top bits, and also ensure that the
return value is in an FP register.
Reviewers: ab, jmolloy
Subscribers: srhines, llvm-commits
Differential Revision: http://reviews.llvm.org/D15438
llvm-svn: 257184
Matt Arsenault