IDIOM 17: overflows of jump table offset computations should be UNKNOWNSIGN checks instead of UNSIGNED.

Detect more benign truncations in IDIOM 2 based on the original source of the truncated operand and its subsequent uses.

Improved detection of truncation idiom 14 and overflow idiom 10 (multiplication by large constant), including fixing IDA Pro operands list for imul opcode.

Expand IDIOM 3 to include subtraction of small immediate from condition code; add IDIOM 13 for all NEGATEDPTR references; increase MEDS propagation of POINTER types.

Benign underflow idioms 11 and 12; subtrahend is large constant, or both operands were obtained from zero-extended moves.

Build RTLs for dryrun lib opcodes; fix uninit vars and clean up code; start mul by large const idiom recognition.

Fix bug in which addressing reg is falsely seen as binary arithmetic reg, causing overflow checks to be UNSIGNED instead of UNKNOWNSIGN (false positives).

Do not allow DEF signedness to become mixed due to propagation of USE operand signedness within an RTL.

Infer signedness from opcodes; suppress overflow and underflow checks on small values from condition codes.