[llvm] [InstCombine] Fold `A == MIN_INT ? MAX_INT : 0 - A` to `ssub_sat 0, A` (PR #194519)

[Antonio Frighetto via llvm-commits]

================
@@ -2154,6 +2154,15 @@ static Instruction *foldSelectICmpEq(SelectInst &SI, ICmpInst *ICI,
   if (Pred == ICmpInst::ICMP_NE)
     std::swap(TrueVal, FalseVal);
 
+  /// `A == MIN_INT ? MAX_INT : 0 - A` --> `ssub_sat 0, A`
+  if (match(CmpRHS, m_MinSignedValue()) && match(TrueVal, m_MaxSignedValue()) &&
+      match(FalseVal, m_Sub(m_ZeroInt(), m_Specific(CmpLHS)))) {
----------------
antoniofrighetto wrote:

```suggestion
      match(FalseVal, m_Neg(m_Specific(CmpLHS)))) {
```

https://github.com/llvm/llvm-project/pull/194519