[llvm] [InstCombine] Factorise Add and Min/Max using Distributivity (PR #101717)

[Nikita Popov via llvm-commits]

================
@@ -1503,6 +1503,76 @@ foldMinimumOverTrailingOrLeadingZeroCount(Value *I0, Value *I1,
       ConstantInt::getTrue(ZeroUndef->getType()));
 }
 
+/// Return whether "X LOp (Y ROp Z)" is always equal to
+/// "(X LOp Y) ROp (X LOp Z)".
+static bool leftDistributesOverRight(Instruction::BinaryOps LOp, bool HasNUW,
+                                     bool HasNSW, Intrinsic::ID ROp) {
+  switch (ROp) {
+  case Intrinsic::umax:
+  case Intrinsic::umin:
+    return hasNUW && LOp == Instruction::Add;
+  case Intrinsic::smax:
+  case Intrinsic::smin:
+    return hasNSW && LOp == Instruction::Add;
----------------
nikic wrote:

```suggestion
    return HasNUW && LOp == Instruction::Add;
  case Intrinsic::smax:
  case Intrinsic::smin:
    return HasNSW && LOp == Instruction::Add;
```

https://github.com/llvm/llvm-project/pull/101717