[llvm-commits] [llvm] r100845 - /llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp

[Dan Gohman]

Author: djg
Date: Thu Apr  8 21:00:38 2010
New Revision: 100845

URL: http://llvm.org/viewvc/llvm-project?rev=100845&view=rev
Log:
Refactor the code for computing the insertion point for an expression into
a separate function.

Modified:
    llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp?rev=100845&r1=100844&r2=100845&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp Thu Apr  8 21:00:38 2010
@@ -1236,6 +1236,10 @@
                     DenseSet<const SCEV *> &VisitedRegs) const;
   void Solve(SmallVectorImpl<const Formula *> &Solution) const;
 
+  BasicBlock::iterator AdjustInputPositionForExpand(BasicBlock::iterator IP,
+                                                    const LSRFixup &LF,
+                                                    const LSRUse &LU) const;
+
   Value *Expand(const LSRFixup &LF,
                 const Formula &F,
                 BasicBlock::iterator IP,
@@ -2801,14 +2805,13 @@
   return Node->getBlock();
 }
 
-Value *LSRInstance::Expand(const LSRFixup &LF,
-                           const Formula &F,
-                           BasicBlock::iterator IP,
-                           SCEVExpander &Rewriter,
-                           SmallVectorImpl<WeakVH> &DeadInsts) const {
-  const LSRUse &LU = Uses[LF.LUIdx];
-
-  // Then, collect some instructions which must be dominated by the
+/// AdjustInputPositionForExpand - Determine an input position which will be
+/// dominated by the operands and which will dominate the result.
+BasicBlock::iterator
+LSRInstance::AdjustInputPositionForExpand(BasicBlock::iterator IP,
+                                          const LSRFixup &LF,
+                                          const LSRUse &LU) const {
+  // Collect some instructions which must be dominated by the
   // expanding replacement. These must be dominated by any operands that
   // will be required in the expansion.
   SmallVector<Instruction *, 4> Inputs;
@@ -2867,9 +2870,27 @@
     else
       IP = Tentative;
   }
+
+  // Don't insert instructions before PHI nodes.
   while (isa<PHINode>(IP)) ++IP;
+
+  // Ignore debug intrinsics.
   while (isa<DbgInfoIntrinsic>(IP)) ++IP;
 
+  return IP;
+}
+
+Value *LSRInstance::Expand(const LSRFixup &LF,
+                           const Formula &F,
+                           BasicBlock::iterator IP,
+                           SCEVExpander &Rewriter,
+                           SmallVectorImpl<WeakVH> &DeadInsts) const {
+  const LSRUse &LU = Uses[LF.LUIdx];
+
+  // Determine an input position which will be dominated by the operands and
+  // which will dominate the result.
+  IP = AdjustInputPositionForExpand(IP, LF, LU);
+
   // Inform the Rewriter if we have a post-increment use, so that it can
   // perform an advantageous expansion.
   Rewriter.setPostInc(LF.PostIncLoops);