[X86] Change the masked FPCLASS implementation to use AND instead of OR to combine...

[X86] Change the masked FPCLASS implementation to use AND instead of OR to combine the mask results.

While the description for the instruction does mention OR, its talking about how the individual classification test results are ORed together.

The incoming mask is used as a zeroing write mask. If the bit is 1 the classification is written to the output. The bit is 0 the output is 0. This equivalent to an AND.

Here is pseudocode from the intrinsics guide

FOR j := 0 to 1
        i := j*64
        IF k1[j]
                k[j] := CheckFPClass_FP64(a[i+63:i], imm8[7:0])
        ELSE
                k[j] := 0
        FI
ENDFOR
k[MAX:2] := 0

llvm-svn: 326306