[llvm] [InstCombine] Simplification for (-a * b) / (a * b). (PR #71768)

[via llvm-commits]

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@@ -1544,6 +1544,14 @@ Instruction *InstCombinerImpl::visitSDiv(BinaryOperator &I) {
     }
   }
 
+  // -X / X --> X == INT_MIN ? 1 : -1
+  if ((match(Op0, m_Sub(m_Zero(), m_Value(X))) && match(Op1, m_Specific(X)))) {
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Z572 wrote:

use isKnownNegation will crash

https://github.com/llvm/llvm-project/pull/71768