[llvm-commits] [llvm] r101083 - /llvm/trunk/lib/Analysis/ScalarEvolution.cpp

[Dan Gohman]

Author: djg
Date: Mon Apr 12 18:03:26 2010
New Revision: 101083

URL: http://llvm.org/viewvc/llvm-project?rev=101083&view=rev
Log:
Add fast paths to ScalarEvolution::getSizeOf and getOffsetOf, as
they're used a lot by getNodeForGEP, which can be called a lot.
This speeds up -iv-users by around 15% on several testcases.

Modified:
    llvm/trunk/lib/Analysis/ScalarEvolution.cpp

Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=101083&r1=101082&r2=101083&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Mon Apr 12 18:03:26 2010
@@ -2254,6 +2254,13 @@
 }
 
 const SCEV *ScalarEvolution::getSizeOfExpr(const Type *AllocTy) {
+  // If we have TargetData, we can bypass creating a target-independent
+  // constant expression and then folding it back into a ConstantInt.
+  // This is just a compile-time optimization.
+  if (TD)
+    return getConstant(TD->getIntPtrType(getContext()),
+                       TD->getTypeAllocSize(AllocTy));
+
   Constant *C = ConstantExpr::getSizeOf(AllocTy);
   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
     C = ConstantFoldConstantExpression(CE, TD);
@@ -2271,6 +2278,13 @@
 
 const SCEV *ScalarEvolution::getOffsetOfExpr(const StructType *STy,
                                              unsigned FieldNo) {
+  // If we have TargetData, we can bypass creating a target-independent
+  // constant expression and then folding it back into a ConstantInt.
+  // This is just a compile-time optimization.
+  if (TD)
+    return getConstant(TD->getIntPtrType(getContext()),
+                       TD->getStructLayout(STy)->getElementOffset(FieldNo));
+
   Constant *C = ConstantExpr::getOffsetOf(STy, FieldNo);
   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
     C = ConstantFoldConstantExpression(CE, TD);