Decompose an icmp into the form ((X & Mask) pred C) if possible.
Declared in <llvm/Analysis/CmpInstAnalysis.h>
std::optional<DecomposedBitTest>
decomposeBitTestICmp(
Value* LHS,
Value* RHS,
CmpInst::Predicate Pred,
bool LookThroughTrunc = true,
bool AllowNonZeroC = false,
bool DecomposeAnd = false);Unless AllowNonZeroC is true, C will always be 0. If DecomposeAnd is specified, then, for equality predicates, this will decompose bitmasking via and.
Decomposed bit-test form when possible; otherwise std::nullopt.
| Name | Description |
|---|---|
| LHS | Left-hand operand of the icmp. |
| RHS | Right-hand operand of the icmp. |
| Pred | Predicate of the icmp to decompose. |
| LookThroughTrunc | When true, look through truncates on the operands. |
| AllowNonZeroC | When true, allow a non-zero constant C. |
| DecomposeAnd | When true, decompose equality bitmasking via and. |