[llvm-commits] [llvm] r53217 - in /llvm/trunk: include/llvm/Analysis/ScalarEvolutionExpander.h lib/Analysis/ScalarEvolutionExpander.cpp

[Nick Lewycky]

Author: nicholas
Date: Tue Jul  8 00:05:37 2008
New Revision: 53217

URL: http://llvm.org/viewvc/llvm-project?rev=53217&view=rev
Log:
Expand SCEVUDiv of power of 2 to a lshr instruction.

Modified:
    llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h
    llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp

Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h?rev=53217&r1=53216&r2=53217&view=diff

==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolutionExpander.h Tue Jul  8 00:05:37 2008
@@ -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);
 

Modified: llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp?rev=53217&r1=53216&r2=53217&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp Tue Jul  8 00:05:37 2008
@@ -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();