[llvm-commits] [llvm] r111151 - /llvm/trunk/lib/Analysis/ScalarEvolution.cpp

[Dan Gohman]

Author: djg
Date: Mon Aug 16 11:57:24 2010
New Revision: 111151

URL: http://llvm.org/viewvc/llvm-project?rev=111151&view=rev
Log:
To create a copy of a SmallVector with an element removed from the
middle, copy the elements in two groups, rather than copying all the
elements and then doing an erase on the middle of the result. These
are SmallVectors, so we shouldn't expect to hit dynamic allocation
in the common case.

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=111151&r1=111150&r2=111151&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Mon Aug 16 11:57:24 2010
@@ -1530,8 +1530,9 @@
           if (Mul->getNumOperands() != 2) {
             // If the multiply has more than two operands, we must get the
             // Y*Z term.
-            SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(), Mul->op_end());
-            MulOps.erase(MulOps.begin()+MulOp);
+            SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(),
+                                                Mul->op_begin()+MulOp);
+            MulOps.append(Mul->op_begin()+MulOp+1, Mul->op_end());
             InnerMul = getMulExpr(MulOps);
           }
           const SCEV *One = getConstant(Ty, 1);
@@ -1564,15 +1565,15 @@
             const SCEV *InnerMul1 = Mul->getOperand(MulOp == 0);
             if (Mul->getNumOperands() != 2) {
               SmallVector<const SCEV *, 4> MulOps(Mul->op_begin(),
-                                                  Mul->op_end());
-              MulOps.erase(MulOps.begin()+MulOp);
+                                                  Mul->op_begin()+MulOp);
+              MulOps.append(Mul->op_begin()+MulOp+1, Mul->op_end());
               InnerMul1 = getMulExpr(MulOps);
             }
             const SCEV *InnerMul2 = OtherMul->getOperand(OMulOp == 0);
             if (OtherMul->getNumOperands() != 2) {
               SmallVector<const SCEV *, 4> MulOps(OtherMul->op_begin(),
-                                                  OtherMul->op_end());
-              MulOps.erase(MulOps.begin()+OMulOp);
+                                                  OtherMul->op_begin()+OMulOp);
+              MulOps.append(OtherMul->op_begin()+OMulOp+1, OtherMul->op_end());
               InnerMul2 = getMulExpr(MulOps);
             }
             const SCEV *InnerMulSum = getAddExpr(InnerMul1,InnerMul2);