[InstSimplify] use m_Specific and commutative matcher to reduce code; NFCI

llvm-svn: 322955

1 files changed, 8 insertions, 9 deletions

diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 9f8e8c9a853..6c6b1cfe720 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -978,18 +978,17 @@ static Value *simplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
   bool IsSigned = Opcode == Instruction::SDiv;
 
   // (X * Y) / Y -> X if the multiplication does not overflow.
-  Value *X = nullptr, *Y = nullptr;
-  if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
-    if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
-    OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
-    // If the Mul knows it does not overflow, then we are good to go.
+  Value *X;
+  if (match(Op0, m_c_Mul(m_Value(X), m_Specific(Op1)))) {
+    auto *Mul = cast<OverflowingBinaryOperator>(Op0);
+    // If the Mul does not overflow, then we are good to go.
     if ((IsSigned && Mul->hasNoSignedWrap()) ||
         (!IsSigned && Mul->hasNoUnsignedWrap()))
       return X;
-    // If X has the form X = A / Y then X * Y cannot overflow.
-    if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
-      if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
-        return X;
+    // If X has the form X = A / Y, then X * Y cannot overflow.
+    if ((IsSigned && match(X, m_SDiv(m_Value(), m_Specific(Op1)))) ||
+        (!IsSigned && match(X, m_UDiv(m_Value(), m_Specific(Op1)))))
+      return X;
   }
 
   // (X rem Y) / Y -> 0