[llvm] Simplify `(a % b) lt/ge (b-1)` into `(a % b) eq/ne (b-1)` (PR #72504)

[Nikita Popov via llvm-commits]

================
@@ -6855,6 +6855,45 @@ Instruction *InstCombinerImpl::visitICmpInst(ICmpInst &I) {
   if (Value *V = simplifyICmpInst(I.getPredicate(), Op0, Op1, Q))
     return replaceInstUsesWith(I, V);
 
+  {
----------------
nikic wrote:

You can add a new foldIcmpURemConstant() function next to foldIcmpSRemConstant() (and add it to the switch).

https://github.com/llvm/llvm-project/pull/72504