llvm-project

807cc379 - [DAGCombiner] Fold subtraction if above threshold to `umin` (#134235)

[DAGCombiner] Fold subtraction if above threshold to `umin` (#134235) Folds patterns such as: unsigned foo(unsigned x, unsigned y) { return x >= y ? x - y : x; } Before, on RISC-V: sltu a2, a0, a1 addi a2, a2, -1 and a1, a1, a2 subw a0, a0, a1 Or, with Zicond: sltu a2, a0, a1 czero.nez a1, a1, a2 subw a0, a0, a1 After, with Zbb: subw a1, a0, a1 minu a0, a0, a1 Only applies to unsigned comparisons. If `x >= y` then `x - y` is less than or equal `x`. Otherwise, `x - y` wraps and is greater than `x`.