lrint/llrint are defined as rounding using the current rounding
mode. Numbers that can't be converted raise FE_INVALID and an
implementation defined value is returned. They may also write to
errno.
I believe this means we can use cvtss2si/cvtsd2si or fist to
convert as long as -fno-math-errno is passed on the command line.
Clang will leave them as libcalls if errno is enabled so they
won't become ISD::LRINT/LLRINT in SelectionDAG.
For 64-bit results on a 32-bit target we can't use cvtss2si/cvtsd2si
but we can use fist since it can write to a 64-bit memory location.
Though maybe we could consider using vcvtps2qq/vcvtpd2qq on avx512dq
targets?
gcc also does this optimization.
I think we might be able to do this with STRICT_LRINT/LLRINT as
well, but I've left that for future work.
Differential Revision: https://reviews.llvm.org/D73859
We don't need tests for truncating the result. There's nothing
special about those truncates.
We can test llrint/llround for 64-bit and 32-bit targets in the same file.
Same with lrint/lround with i32 result result. lrint/lround with
64-bit result should only occur on a 64-bit target.
Add some missing tests for f80 conversions.
This patch add the ISD::LRINT and ISD::LLRINT along with new
intrinsics. The changes are straightforward as for other
floating-point rounding functions, with just some adjustments
required to handle the return value being an interger.
The idea is to optimize lrint/llrint generation for AArch64
in a subsequent patch. Current semantic is just route it to libm
symbol.
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D62017
llvm-svn: 361875
