09029045a8
Add the following folds for integer min max folding in InstCombine: - (X > Y) ? X : (Y - 1) ==> MIN(X, Y - 1) - (X < Y) ? X : (Y + 1) ==> MAX(X, Y + 1) These are safe when overflow corresponding to the sign of the comparison is poison. (proof https://alive2.llvm.org/ce/z/oj5iiI). The most common of these patterns is likely the minimum case which occurs in some internal library code when clamping an integer index to a range (The maximum cases are included for completeness). Here is a simplified example: int clampToWidth(int idx, int width) { if (idx >= width) return width - 1; return idx; } https://cuda.godbolt.org/z/nhPzWrc3W