// Note that BTx instructions use the carry bit, so we need to convert tests for zero flag
// into tests for carry flags.
// ULT and SETB check the carry flag; they are identical to CS and SETCS. Same, mutatis
// mutandis, for UGE and SETAE, and CC and SETCC.
((NE|EQ) (TESTL (SHLL (MOVLconst [1]) x) y)) => ((ULT|UGE) (BTL x y))
((NE|EQ) (TESTQ (SHLQ (MOVQconst [1]) x) y)) => ((ULT|UGE) (BTQ x y))