[llvm] [InstSimplify] Simplify the select with integer comparison relationship (PR #66668)

[via llvm-commits]

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@@ -8282,6 +8282,28 @@ static std::optional<bool> isImpliedCondICmps(const ICmpInst *LHS,
   if (areMatchingOperands(L0, L1, R0, R1, AreSwappedOps))
     return isImpliedCondMatchingOperands(LPred, RPred, AreSwappedOps);
 
+  if (RPred == ICmpInst::ICMP_SLE) {
+    Value *X;
+    Value *Y;
+    // x -nsw y <= -1 <==> x < y
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vfdff wrote:

you'll see now we also can't optimize the following case
```
#include <stdlib.h>
int test_slt (int x, int y) {
  return x<y ? abs (x-y+1): 0;   // here `x-y+1 <= 0`
}
```

https://github.com/llvm/llvm-project/pull/66668