[InstCombine] Refactor powi(X,Y) / X to call foldPowiReassoc, NFC

Author: vfdff

llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp

@@ -611,6 +611,18 @@ Instruction *InstCombinerImpl::foldPowiReassoc(BinaryOperator &I) {
       Y->getType() == Z->getType())
     return createPowiExpr(I, *this, X, Y, Z);
 
+  // powi(X, Y) / X --> powi(X, Y-1)
+  // This is legal when (Y - 1) can't wraparound, in which case reassoc and nnan
+  // are required.
+  // TODO: Multi-use may be also better off creating Powi(x,y-1)
+  if (I.hasAllowReassoc() && I.hasNoNaNs() &&
+      match(Op0, m_OneUse(m_Intrinsic<Intrinsic::powi>(m_Specific(Op1),
+                                                       m_Value(Y)))) &&
+      willNotOverflowSignedSub(Y, ConstantInt::get(Y->getType(), 1), I)) {
+    Constant *NegOne = ConstantInt::getAllOnesValue(Y->getType());
+    return createPowiExpr(I, *this, Op1, Y, NegOne);
+  }
+
   return nullptr;
 }
 
@@ -1904,20 +1916,8 @@ Instruction *InstCombinerImpl::visitFDiv(BinaryOperator &I) {
     return replaceInstUsesWith(I, Pow);
   }
 
-  // powi(X, Y) / X --> powi(X, Y-1)
-  // This is legal when (Y - 1) can't wraparound, in which case reassoc and nnan
-  // are required.
-  // TODO: Multi-use may be also better off creating Powi(x,y-1)
-  if (I.hasAllowReassoc() && I.hasNoNaNs() &&
-      match(Op0, m_OneUse(m_Intrinsic<Intrinsic::powi>(m_Specific(Op1),
-                                                       m_Value(Y)))) &&
-      willNotOverflowSignedSub(Y, ConstantInt::get(Y->getType(), 1), I)) {
-    Constant *NegOne = ConstantInt::getAllOnesValue(Y->getType());
-    Value *Y1 = Builder.CreateAdd(Y, NegOne);
-    Type *Types[] = {Op1->getType(), Y1->getType()};
-    Value *Pow = Builder.CreateIntrinsic(Intrinsic::powi, Types, {Op1, Y1}, &I);
-    return replaceInstUsesWith(I, Pow);
-  }
+  if (Instruction *FoldedPowi = foldPowiReassoc(I))
+    return FoldedPowi;
 
   return nullptr;
 }