Expand SCEVUDiv of power of 2 to a lshr instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53217 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/Analysis/ScalarEvolutionExpander.h b/include/llvm/Analysis/ScalarEvolutionExpander.h
index bd9596c..cd075ef 100644
--- a/include/llvm/Analysis/ScalarEvolutionExpander.h
+++ b/include/llvm/Analysis/ScalarEvolutionExpander.h
@@ -102,11 +102,7 @@
Value *visitMulExpr(SCEVMulExpr *S);
- Value *visitUDivExpr(SCEVUDivExpr *S) {
- Value *LHS = expand(S->getLHS());
- Value *RHS = expand(S->getRHS());
- return InsertBinop(Instruction::UDiv, LHS, RHS, InsertPt);
- }
+ Value *visitUDivExpr(SCEVUDivExpr *S);
Value *visitAddRecExpr(SCEVAddRecExpr *S);
diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index 593e273..628129d 100644
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -129,6 +129,20 @@
return V;
}
+Value *SCEVExpander::visitUDivExpr(SCEVUDivExpr *S) {
+ Value *LHS = expand(S->getLHS());
+ if (SCEVConstant *SC = dyn_cast<SCEVConstant>(S->getRHS())) {
+ const APInt &RHS = SC->getValue()->getValue();
+ if (RHS.isPowerOf2())
+ return InsertBinop(Instruction::LShr, LHS,
+ ConstantInt::get(S->getType(), RHS.logBase2()),
+ InsertPt);
+ }
+
+ Value *RHS = expand(S->getRHS());
+ return InsertBinop(Instruction::UDiv, LHS, RHS, InsertPt);
+}
+
Value *SCEVExpander::visitAddRecExpr(SCEVAddRecExpr *S) {
const Type *Ty = S->getType();
const Loop *L = S->getLoop();