[X86][InstCombine] Remove InstCombine code that turns X86 round intrinsics into llvm.ceil/floor. Remove some isel patterns that existed because that was happening.

We were turning roundss/sd/ps/pd intrinsics with immediates of 1 or 2 into
llvm.floor/ceil.  The llvm.ceil/floor intrinsics are supposed to correspond
to the libm functions.  For the libm functions we need to disable the
precision exception so the llvm.floor/ceil functions should always map to
encodings 0x9 and 0xA.

We had a mix of isel patterns where some used 0x9 and 0xA and others used
0x1 and 0x2. We need to be consistent and always use 0x9 and 0xA.

Since we have no way in isel of knowing where the llvm.ceil/floor came
from, we can't map X86 specific intrinsics with encodings 1 or 2 to it.
We could map 0x9 and 0xA to llvm.ceil/floor instead, but I'd really like
to see a use case and optimization advantage first.

I've left the backend test cases to show the blend we now emit without
the extra isel patterns. But I've removed the InstCombine tests completely.

llvm-svn: 361425

0 files changed, 0 insertions, 0 deletions