[InstCombine] Allow min/max in constant BOp min/max folding (#142878)

Extend folding for `X Pred C2 ? X BOp C1 : C2 BOp C1` to `min/max(X, C2)
BOp C1` to allow min and max as `BOp`. This ensures a constant clamping
pattern is folded into a pair of min/max instructions. Here is a
simplified example of a case where this folding is not occurring
currently.

int clampToU8(int v) {
    if (v < 0) return 0;
    if (v > 255) return 255;
    return v;
}

https://godbolt.org/z/78jhKPWbv

Generic proof: https://alive2.llvm.org/ce/z/cdpLYy

0 files changed, 0 insertions, 0 deletions