[llvm-branch-commits] [llvm-branch] r101103 - in /llvm/branches/Apple/Morbo: include/llvm/Analysis/ lib/Analysis/ lib/Transforms/Scalar/ test/CodeGen/X86/ test/Transforms/LoopStrengthReduce/

Dan Gohman gohman at apple.com
Mon Apr 12 17:21:38 PDT 2010


Author: djg
Date: Mon Apr 12 19:21:38 2010
New Revision: 101103

URL: http://llvm.org/viewvc/llvm-project?rev=101103&view=rev
Log:
$ svn merge -c 100515 https://djg@llvm.org/svn/llvm-project/llvm/trunk
--- Merging r100515 into '.':
U    lib/Analysis/IVUsers.cpp
$ svn merge -c 100699 https://djg@llvm.org/svn/llvm-project/llvm/trunk
--- Merging r100699 into '.':
U    test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll
A    test/CodeGen/X86/multiple-loop-post-inc.ll
A    include/llvm/Analysis/ScalarEvolutionNormalization.h
U    include/llvm/Analysis/IVUsers.h
U    include/llvm/Analysis/ScalarEvolutionExpander.h
G    lib/Analysis/IVUsers.cpp
U    lib/Analysis/ScalarEvolutionExpander.cpp
A    lib/Analysis/ScalarEvolutionNormalization.cpp
U    lib/Transforms/Scalar/IndVarSimplify.cpp
U    lib/Transforms/Scalar/LoopStrengthReduce.cpp
$ svn merge -c 100748 https://djg@llvm.org/svn/llvm-project/llvm/trunk
--- Merging r100748 into '.':
U    test/CodeGen/X86/multiple-loop-post-inc.ll
G    lib/Transforms/Scalar/LoopStrengthReduce.cpp
$ svn merge -c 100749 https://djg@llvm.org/svn/llvm-project/llvm/trunk
--- Merging r100749 into '.':
U    lib/Analysis/ScalarEvolution.cpp
$ svn merge -c 100828 https://djg@llvm.org/svn/llvm-project/llvm/trunk
--- Merging r100828 into '.':
G    lib/Transforms/Scalar/LoopStrengthReduce.cpp
$ svn merge -c 100839 https://djg@llvm.org/svn/llvm-project/llvm/trunk
--- Merging r100839 into '.':
A    test/Transforms/LoopStrengthReduce/insert-positions.ll
G    lib/Analysis/IVUsers.cpp
$ svn merge -c 100845 https://djg@llvm.org/svn/llvm-project/llvm/trunk
--- Merging r100845 into '.':
G    lib/Transforms/Scalar/LoopStrengthReduce.cpp
$ svn merge -c 100874 https://djg@llvm.org/svn/llvm-project/llvm/trunk
--- Merging r100874 into '.':
G    lib/Analysis/ScalarEvolutionExpander.cpp
$ svn merge -c 100883 https://djg@llvm.org/svn/llvm-project/llvm/trunk
--- Merging r100883 into '.':
G    lib/Transforms/Scalar/LoopStrengthReduce.cpp
$ svn merge -c 100884 https://djg@llvm.org/svn/llvm-project/llvm/trunk
--- Merging r100884 into '.':
A    test/Transforms/LoopStrengthReduce/uglygep.ll
G    lib/Analysis/ScalarEvolutionExpander.cpp
$ svn merge -c 100906 https://djg@llvm.org/svn/llvm-project/llvm/trunk
--- Merging r100906 into '.':
U    test/Transforms/LoopStrengthReduce/uglygep.ll
G    lib/Transforms/Scalar/LoopStrengthReduce.cpp
$ svn merge -c 101033 https://djg@llvm.org/svn/llvm-project/llvm/trunk
--- Merging r101033 into '.':
G    lib/Transforms/Scalar/LoopStrengthReduce.cpp

Added:
    llvm/branches/Apple/Morbo/include/llvm/Analysis/ScalarEvolutionNormalization.h
      - copied unchanged from r100699, llvm/trunk/include/llvm/Analysis/ScalarEvolutionNormalization.h
    llvm/branches/Apple/Morbo/lib/Analysis/ScalarEvolutionNormalization.cpp
      - copied unchanged from r100699, llvm/trunk/lib/Analysis/ScalarEvolutionNormalization.cpp
    llvm/branches/Apple/Morbo/test/CodeGen/X86/multiple-loop-post-inc.ll
      - copied, changed from r100699, llvm/trunk/test/CodeGen/X86/multiple-loop-post-inc.ll
    llvm/branches/Apple/Morbo/test/Transforms/LoopStrengthReduce/insert-positions.ll
      - copied unchanged from r100839, llvm/trunk/test/Transforms/LoopStrengthReduce/insert-positions.ll
    llvm/branches/Apple/Morbo/test/Transforms/LoopStrengthReduce/uglygep.ll
      - copied, changed from r100884, llvm/trunk/test/Transforms/LoopStrengthReduce/uglygep.ll
Modified:
    llvm/branches/Apple/Morbo/include/llvm/Analysis/IVUsers.h
    llvm/branches/Apple/Morbo/include/llvm/Analysis/ScalarEvolutionExpander.h
    llvm/branches/Apple/Morbo/lib/Analysis/IVUsers.cpp
    llvm/branches/Apple/Morbo/lib/Analysis/ScalarEvolution.cpp
    llvm/branches/Apple/Morbo/lib/Analysis/ScalarEvolutionExpander.cpp
    llvm/branches/Apple/Morbo/lib/Transforms/Scalar/IndVarSimplify.cpp
    llvm/branches/Apple/Morbo/lib/Transforms/Scalar/LoopStrengthReduce.cpp
    llvm/branches/Apple/Morbo/test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll

Modified: llvm/branches/Apple/Morbo/include/llvm/Analysis/IVUsers.h
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Morbo/include/llvm/Analysis/IVUsers.h?rev=101103&r1=101102&r2=101103&view=diff
==============================================================================
--- llvm/branches/Apple/Morbo/include/llvm/Analysis/IVUsers.h (original)
+++ llvm/branches/Apple/Morbo/include/llvm/Analysis/IVUsers.h Mon Apr 12 19:21:38 2010
@@ -16,6 +16,7 @@
 #define LLVM_ANALYSIS_IVUSERS_H
 
 #include "llvm/Analysis/LoopPass.h"
+#include "llvm/Analysis/ScalarEvolutionNormalization.h"
 #include "llvm/Support/ValueHandle.h"
 
 namespace llvm {
@@ -26,17 +27,18 @@
 class IVUsers;
 class ScalarEvolution;
 class SCEV;
+class IVUsers;
 
 /// IVStrideUse - Keep track of one use of a strided induction variable.
 /// The Expr member keeps track of the expression, User is the actual user
 /// instruction of the operand, and 'OperandValToReplace' is the operand of
 /// the User that is the use.
 class IVStrideUse : public CallbackVH, public ilist_node<IVStrideUse> {
+  friend class IVUsers;
 public:
-  IVStrideUse(IVUsers *P, const SCEV *S, const SCEV *Off,
+  IVStrideUse(IVUsers *P, const SCEV *E,
               Instruction* U, Value *O)
-    : CallbackVH(U), Parent(P), Stride(S), Offset(Off),
-      OperandValToReplace(O), IsUseOfPostIncrementedValue(false) {
+    : CallbackVH(U), Parent(P), Expr(E), OperandValToReplace(O) {
   }
 
   /// getUser - Return the user instruction for this use.
@@ -53,24 +55,16 @@
   /// this IVStrideUse.
   IVUsers *getParent() const { return Parent; }
 
-  /// getStride - Return the expression for the stride for the use.
-  const SCEV *getStride() const { return Stride; }
+  /// getExpr - Return the expression for the use.
+  const SCEV *getExpr() const { return Expr; }
 
-  /// setStride - Assign a new stride to this use.
-  void setStride(const SCEV *Val) {
-    Stride = Val;
-  }
-
-  /// getOffset - Return the offset to add to a theoretical induction
-  /// variable that starts at zero and counts up by the stride to compute
-  /// the value for the use. This always has the same type as the stride.
-  const SCEV *getOffset() const { return Offset; }
-
-  /// setOffset - Assign a new offset to this use.
-  void setOffset(const SCEV *Val) {
-    Offset = Val;
+  /// setExpr - Assign a new expression to this use.
+  void setExpr(const SCEV *Val) {
+    Expr = Val;
   }
 
+  const SCEV *getStride(const Loop *L) const;
+
   /// getOperandValToReplace - Return the Value of the operand in the user
   /// instruction that this IVStrideUse is representing.
   Value *getOperandValToReplace() const {
@@ -83,37 +77,30 @@
     OperandValToReplace = Op;
   }
 
-  /// isUseOfPostIncrementedValue - True if this should use the
-  /// post-incremented version of this IV, not the preincremented version.
-  /// This can only be set in special cases, such as the terminating setcc
-  /// instruction for a loop or uses dominated by the loop.
-  bool isUseOfPostIncrementedValue() const {
-    return IsUseOfPostIncrementedValue;
+  /// getPostIncLoops - Return the set of loops for which the expression has
+  /// been adjusted to use post-inc mode.
+  const PostIncLoopSet &getPostIncLoops() const {
+    return PostIncLoops;
   }
 
-  /// setIsUseOfPostIncrmentedValue - set the flag that indicates whether
-  /// this is a post-increment use.
-  void setIsUseOfPostIncrementedValue(bool Val) {
-    IsUseOfPostIncrementedValue = Val;
-  }
+  /// transformToPostInc - Transform the expression to post-inc form for the
+  /// given loop.
+  void transformToPostInc(const Loop *L);
 
 private:
   /// Parent - a pointer to the IVUsers that owns this IVStrideUse.
   IVUsers *Parent;
 
-  /// Stride - The stride for this use.
-  const SCEV *Stride;
-
-  /// Offset - The offset to add to the base induction expression.
-  const SCEV *Offset;
+  /// Expr - The expression for this use.
+  const SCEV *Expr;
 
   /// OperandValToReplace - The Value of the operand in the user instruction
   /// that this IVStrideUse is representing.
   WeakVH OperandValToReplace;
 
-  /// IsUseOfPostIncrementedValue - True if this should use the
-  /// post-incremented version of this IV, not the preincremented version.
-  bool IsUseOfPostIncrementedValue;
+  /// PostIncLoops - The set of loops for which Expr has been adjusted to
+  /// use post-inc mode. This corresponds with SCEVExpander's post-inc concept.
+  PostIncLoopSet PostIncLoops;
 
   /// Deleted - Implementation of CallbackVH virtual function to
   /// receive notification when the User is deleted.
@@ -174,18 +161,13 @@
   /// return true.  Otherwise, return false.
   bool AddUsersIfInteresting(Instruction *I);
 
-  IVStrideUse &AddUser(const SCEV *Stride, const SCEV *Offset,
+  IVStrideUse &AddUser(const SCEV *Expr,
                        Instruction *User, Value *Operand);
 
   /// getReplacementExpr - Return a SCEV expression which computes the
   /// value of the OperandValToReplace of the given IVStrideUse.
   const SCEV *getReplacementExpr(const IVStrideUse &U) const;
 
-  /// getCanonicalExpr - Return a SCEV expression which computes the
-  /// value of the SCEV of the given IVStrideUse, ignoring the 
-  /// isUseOfPostIncrementedValue flag.
-  const SCEV *getCanonicalExpr(const IVStrideUse &U) const;
-
   typedef ilist<IVStrideUse>::iterator iterator;
   typedef ilist<IVStrideUse>::const_iterator const_iterator;
   iterator begin() { return IVUses.begin(); }

Modified: llvm/branches/Apple/Morbo/include/llvm/Analysis/ScalarEvolutionExpander.h
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Morbo/include/llvm/Analysis/ScalarEvolutionExpander.h?rev=101103&r1=101102&r2=101103&view=diff
==============================================================================
--- llvm/branches/Apple/Morbo/include/llvm/Analysis/ScalarEvolutionExpander.h (original)
+++ llvm/branches/Apple/Morbo/include/llvm/Analysis/ScalarEvolutionExpander.h Mon Apr 12 19:21:38 2010
@@ -15,6 +15,7 @@
 #define LLVM_ANALYSIS_SCALAREVOLUTION_EXPANDER_H
 
 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
+#include "llvm/Analysis/ScalarEvolutionNormalization.h"
 #include "llvm/Support/IRBuilder.h"
 #include "llvm/Support/TargetFolder.h"
 #include <set>
@@ -32,12 +33,12 @@
       InsertedExpressions;
     std::set<Value*> InsertedValues;
 
-    /// PostIncLoop - When non-null, expanded addrecs referring to the given
-    /// loop expanded in post-inc mode. For example, expanding {1,+,1}<L> in
-    /// post-inc mode returns the add instruction that adds one to the phi
-    /// for {0,+,1}<L>, as opposed to a new phi starting at 1. This is only
-    /// supported in non-canonical mode.
-    const Loop *PostIncLoop;
+    /// PostIncLoops - Addrecs referring to any of the given loops are expanded
+    /// in post-inc mode. For example, expanding {1,+,1}<L> in post-inc mode
+    /// returns the add instruction that adds one to the phi for {0,+,1}<L>,
+    /// as opposed to a new phi starting at 1. This is only supported in
+    /// non-canonical mode.
+    PostIncLoopSet PostIncLoops;
 
     /// IVIncInsertPos - When this is non-null, addrecs expanded in the
     /// loop it indicates should be inserted with increments at
@@ -62,7 +63,7 @@
   public:
     /// SCEVExpander - Construct a SCEVExpander in "canonical" mode.
     explicit SCEVExpander(ScalarEvolution &se)
-      : SE(se), PostIncLoop(0), IVIncInsertLoop(0), CanonicalMode(true),
+      : SE(se), IVIncInsertLoop(0), CanonicalMode(true),
         Builder(se.getContext(), TargetFolder(se.TD)) {}
 
     /// clear - Erase the contents of the InsertedExpressions map so that users
@@ -89,14 +90,18 @@
       IVIncInsertPos = Pos;
     }
 
-    /// setPostInc - If L is non-null, enable post-inc expansion for addrecs
-    /// referring to the given loop. If L is null, disable post-inc expansion
-    /// completely. Post-inc expansion is only supported in non-canonical
+    /// setPostInc - Enable post-inc expansion for addrecs referring to the
+    /// given loops. Post-inc expansion is only supported in non-canonical
     /// mode.
-    void setPostInc(const Loop *L) {
+    void setPostInc(const PostIncLoopSet &L) {
       assert(!CanonicalMode &&
              "Post-inc expansion is not supported in CanonicalMode");
-      PostIncLoop = L;
+      PostIncLoops = L;
+    }
+
+    /// clearPostInc - Disable all post-inc expansion.
+    void clearPostInc() {
+      PostIncLoops.clear();
     }
 
     /// disableCanonicalMode - Disable the behavior of expanding expressions in

Modified: llvm/branches/Apple/Morbo/lib/Analysis/IVUsers.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Morbo/lib/Analysis/IVUsers.cpp?rev=101103&r1=101102&r2=101103&view=diff
==============================================================================
--- llvm/branches/Apple/Morbo/lib/Analysis/IVUsers.cpp (original)
+++ llvm/branches/Apple/Morbo/lib/Analysis/IVUsers.cpp Mon Apr 12 19:21:38 2010
@@ -62,120 +62,34 @@
   Ops.push_back(S);
 }
 
-/// getSCEVStartAndStride - Compute the start and stride of this expression,
-/// returning false if the expression is not a start/stride pair, or true if it
-/// is.  The stride must be a loop invariant expression, but the start may be
-/// a mix of loop invariant and loop variant expressions.  The start cannot,
-/// however, contain an AddRec from a different loop, unless that loop is an
-/// outer loop of the current loop.
-static bool getSCEVStartAndStride(const SCEV *&SH, Loop *L, Loop *UseLoop,
-                                  const SCEV *&Start, const SCEV *&Stride,
-                                  ScalarEvolution *SE, DominatorTree *DT) {
-  const SCEV *TheAddRec = Start;   // Initialize to zero.
-
-  // If the outer level is an AddExpr, the operands are all start values except
-  // for a nested AddRecExpr.
-  if (const SCEVAddExpr *AE = dyn_cast<SCEVAddExpr>(SH)) {
-    for (unsigned i = 0, e = AE->getNumOperands(); i != e; ++i)
-      if (const SCEVAddRecExpr *AddRec =
-             dyn_cast<SCEVAddRecExpr>(AE->getOperand(i)))
-        TheAddRec = SE->getAddExpr(AddRec, TheAddRec);
-      else
-        Start = SE->getAddExpr(Start, AE->getOperand(i));
-  } else if (isa<SCEVAddRecExpr>(SH)) {
-    TheAddRec = SH;
-  } else {
-    return false;  // not analyzable.
-  }
-
-  // Break down TheAddRec into its component parts.
-  SmallVector<const SCEV *, 4> Subexprs;
-  CollectSubexprs(TheAddRec, Subexprs, *SE);
-
-  // Look for an addrec on the current loop among the parts.
-  const SCEV *AddRecStride = 0;
-  for (SmallVectorImpl<const SCEV *>::iterator I = Subexprs.begin(),
-       E = Subexprs.end(); I != E; ++I) {
-    const SCEV *S = *I;
-    if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S))
-      if (AR->getLoop() == L) {
-        *I = AR->getStart();
-        AddRecStride = AR->getStepRecurrence(*SE);
-        break;
-      }
-  }
-  if (!AddRecStride)
-    return false;
+/// isInteresting - Test whether the given expression is "interesting" when
+/// used by the given expression, within the context of analyzing the
+/// given loop.
+static bool isInteresting(const SCEV *S, const Instruction *I, const Loop *L) {
+  // Anything loop-invariant is interesting.
+  if (!isa<SCEVUnknown>(S) && S->isLoopInvariant(L))
+    return true;
 
-  // Add up everything else into a start value (which may not be
-  // loop-invariant).
-  const SCEV *AddRecStart = SE->getAddExpr(Subexprs);
-
-  // Use getSCEVAtScope to attempt to simplify other loops out of
-  // the picture.
-  AddRecStart = SE->getSCEVAtScope(AddRecStart, UseLoop);
-
-  Start = SE->getAddExpr(Start, AddRecStart);
-
-  // If stride is an instruction, make sure it properly dominates the header.
-  // Otherwise we could end up with a use before def situation.
-  if (!isa<SCEVConstant>(AddRecStride)) {
-    BasicBlock *Header = L->getHeader();
-    if (!AddRecStride->properlyDominates(Header, DT))
-      return false;
-
-    DEBUG(dbgs() << "[";
-          WriteAsOperand(dbgs(), L->getHeader(), /*PrintType=*/false);
-          dbgs() << "] Variable stride: " << *AddRecStride << "\n");
+  // An addrec is interesting if it's affine or if it has an interesting start.
+  if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
+    // Keep things simple. Don't touch loop-variant strides.
+    if (AR->getLoop() == L)
+      return AR->isAffine() || !L->contains(I);
+    // Otherwise recurse to see if the start value is interesting.
+    return isInteresting(AR->getStart(), I, L);
   }
 
-  Stride = AddRecStride;
-  return true;
-}
-
-/// IVUseShouldUsePostIncValue - We have discovered a "User" of an IV expression
-/// and now we need to decide whether the user should use the preinc or post-inc
-/// value.  If this user should use the post-inc version of the IV, return true.
-///
-/// Choosing wrong here can break dominance properties (if we choose to use the
-/// post-inc value when we cannot) or it can end up adding extra live-ranges to
-/// the loop, resulting in reg-reg copies (if we use the pre-inc value when we
-/// should use the post-inc value).
-static bool IVUseShouldUsePostIncValue(Instruction *User, Instruction *IV,
-                                       Loop *L, DominatorTree *DT) {
-  // If the user is in the loop, use the preinc value.
-  if (L->contains(User)) return false;
-
-  BasicBlock *LatchBlock = L->getLoopLatch();
-  if (!LatchBlock)
+  // An add is interesting if any of its operands is.
+  if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
+    for (SCEVAddExpr::op_iterator OI = Add->op_begin(), OE = Add->op_end();
+         OI != OE; ++OI)
+      if (isInteresting(*OI, I, L))
+        return true;
     return false;
+  }
 
-  // Ok, the user is outside of the loop.  If it is dominated by the latch
-  // block, use the post-inc value.
-  if (DT->dominates(LatchBlock, User->getParent()))
-    return true;
-
-  // There is one case we have to be careful of: PHI nodes.  These little guys
-  // can live in blocks that are not dominated by the latch block, but (since
-  // their uses occur in the predecessor block, not the block the PHI lives in)
-  // should still use the post-inc value.  Check for this case now.
-  PHINode *PN = dyn_cast<PHINode>(User);
-  if (!PN) return false;  // not a phi, not dominated by latch block.
-
-  // Look at all of the uses of IV by the PHI node.  If any use corresponds to
-  // a block that is not dominated by the latch block, give up and use the
-  // preincremented value.
-  unsigned NumUses = 0;
-  for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
-    if (PN->getIncomingValue(i) == IV) {
-      ++NumUses;
-      if (!DT->dominates(LatchBlock, PN->getIncomingBlock(i)))
-        return false;
-    }
-
-  // Okay, all uses of IV by PN are in predecessor blocks that really are
-  // dominated by the latch block.  Use the post-incremented value.
-  return true;
+  // Nothing else is interesting here.
+  return false;
 }
 
 /// AddUsersIfInteresting - Inspect the specified instruction.  If it is a
@@ -196,16 +110,9 @@
   const SCEV *ISE = SE->getSCEV(I);
   if (isa<SCEVCouldNotCompute>(ISE)) return false;
 
-  // Get the start and stride for this expression.
-  Loop *UseLoop = LI->getLoopFor(I->getParent());
-  const SCEV *Start = SE->getIntegerSCEV(0, ISE->getType());
-  const SCEV *Stride = Start;
-
-  if (!getSCEVStartAndStride(ISE, L, UseLoop, Start, Stride, SE, DT))
-    return false;  // Non-reducible symbolic expression, bail out.
-
-  // Keep things simple. Don't touch loop-variant strides.
-  if (!Stride->isLoopInvariant(L) && L->contains(I))
+  // If we've come to an uninteresting expression, stop the traversal and
+  // call this a user.
+  if (!isInteresting(ISE, I, L))
     return false;
 
   SmallPtrSet<Instruction *, 4> UniqueUsers;
@@ -241,27 +148,24 @@
     }
 
     if (AddUserToIVUsers) {
-      // Okay, we found a user that we cannot reduce.  Analyze the instruction
-      // and decide what to do with it.  If we are a use inside of the loop, use
-      // the value before incrementation, otherwise use it after incrementation.
-      if (IVUseShouldUsePostIncValue(User, I, L, DT)) {
-        // The value used will be incremented by the stride more than we are
-        // expecting, so subtract this off.
-        const SCEV *NewStart = SE->getMinusSCEV(Start, Stride);
-        IVUses.push_back(new IVStrideUse(this, Stride, NewStart, User, I));
-        IVUses.back().setIsUseOfPostIncrementedValue(true);
-        DEBUG(dbgs() << "   USING POSTINC SCEV, START=" << *NewStart<< "\n");
-      } else {
-        IVUses.push_back(new IVStrideUse(this, Stride, Start, User, I));
-      }
+      // Okay, we found a user that we cannot reduce.
+      IVUses.push_back(new IVStrideUse(this, ISE, User, I));
+      IVStrideUse &NewUse = IVUses.back();
+      // Transform the expression into a normalized form.
+      NewUse.Expr =
+        TransformForPostIncUse(NormalizeAutodetect, NewUse.Expr,
+                               User, I,
+                               NewUse.PostIncLoops,
+                               *SE, *DT);
+      DEBUG(dbgs() << "   NORMALIZED TO: " << *NewUse.Expr << '\n');
     }
   }
   return true;
 }
 
-IVStrideUse &IVUsers::AddUser(const SCEV *Stride, const SCEV *Offset,
+IVStrideUse &IVUsers::AddUser(const SCEV *Expr,
                               Instruction *User, Value *Operand) {
-  IVUses.push_back(new IVStrideUse(this, Stride, Offset, User, Operand));
+  IVUses.push_back(new IVStrideUse(this, Expr, User, Operand));
   return IVUses.back();
 }
 
@@ -295,30 +199,10 @@
 /// getReplacementExpr - Return a SCEV expression which computes the
 /// value of the OperandValToReplace of the given IVStrideUse.
 const SCEV *IVUsers::getReplacementExpr(const IVStrideUse &U) const {
-  // Start with zero.
-  const SCEV *RetVal = SE->getIntegerSCEV(0, U.getStride()->getType());
-  // Create the basic add recurrence.
-  RetVal = SE->getAddRecExpr(RetVal, U.getStride(), L);
-  // Add the offset in a separate step, because it may be loop-variant.
-  RetVal = SE->getAddExpr(RetVal, U.getOffset());
-  // For uses of post-incremented values, add an extra stride to compute
-  // the actual replacement value.
-  if (U.isUseOfPostIncrementedValue())
-    RetVal = SE->getAddExpr(RetVal, U.getStride());
-  return RetVal;
-}
-
-/// getCanonicalExpr - Return a SCEV expression which computes the
-/// value of the SCEV of the given IVStrideUse, ignoring the 
-/// isUseOfPostIncrementedValue flag.
-const SCEV *IVUsers::getCanonicalExpr(const IVStrideUse &U) const {
-  // Start with zero.
-  const SCEV *RetVal = SE->getIntegerSCEV(0, U.getStride()->getType());
-  // Create the basic add recurrence.
-  RetVal = SE->getAddRecExpr(RetVal, U.getStride(), L);
-  // Add the offset in a separate step, because it may be loop-variant.
-  RetVal = SE->getAddExpr(RetVal, U.getOffset());
-  return RetVal;
+  PostIncLoopSet &Loops = const_cast<PostIncLoopSet &>(U.PostIncLoops);
+  return TransformForPostIncUse(Denormalize, U.getExpr(),
+                                U.getUser(), U.getOperandValToReplace(),
+                                Loops, *SE, *DT);
 }
 
 void IVUsers::print(raw_ostream &OS, const Module *M) const {
@@ -339,8 +223,13 @@
     WriteAsOperand(OS, UI->getOperandValToReplace(), false);
     OS << " = "
        << *getReplacementExpr(*UI);
-    if (UI->isUseOfPostIncrementedValue())
-      OS << " (post-inc)";
+    for (PostIncLoopSet::const_iterator
+         I = UI->PostIncLoops.begin(),
+         E = UI->PostIncLoops.end(); I != E; ++I) {
+      OS << " (post-inc with loop ";
+      WriteAsOperand(OS, (*I)->getHeader(), false);
+      OS << ")";
+    }
     OS << " in  ";
     UI->getUser()->print(OS, &Annotator);
     OS << '\n';
@@ -356,6 +245,39 @@
   IVUses.clear();
 }
 
+static const SCEVAddRecExpr *findAddRecForLoop(const SCEV *S, const Loop *L) {
+  if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
+    if (AR->getLoop() == L)
+      return AR;
+    return findAddRecForLoop(AR->getStart(), L);
+  }
+
+  if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
+    for (SCEVAddExpr::op_iterator I = Add->op_begin(), E = Add->op_end();
+         I != E; ++I)
+      if (const SCEVAddRecExpr *AR = findAddRecForLoop(*I, L))
+        return AR;
+    return 0;
+  }
+
+  return 0;
+}
+
+const SCEV *IVStrideUse::getStride(const Loop *L) const {
+  if (const SCEVAddRecExpr *AR = findAddRecForLoop(getExpr(), L))
+    return AR->getStepRecurrence(*Parent->SE);
+  return 0;
+}
+
+void IVStrideUse::transformToPostInc(const Loop *L) {
+  PostIncLoopSet Loops;
+  Loops.insert(L);
+  Expr = TransformForPostIncUse(Normalize, Expr,
+                                getUser(), getOperandValToReplace(),
+                                Loops, *Parent->SE, *Parent->DT);
+  PostIncLoops.insert(L);
+}
+
 void IVStrideUse::deleted() {
   // Remove this user from the list.
   Parent->IVUses.erase(this);

Modified: llvm/branches/Apple/Morbo/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Morbo/lib/Analysis/ScalarEvolution.cpp?rev=101103&r1=101102&r2=101103&view=diff
==============================================================================
--- llvm/branches/Apple/Morbo/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/branches/Apple/Morbo/lib/Analysis/ScalarEvolution.cpp Mon Apr 12 19:21:38 2010
@@ -3123,8 +3123,6 @@
     return getConstant(CI);
   else if (isa<ConstantPointerNull>(V))
     return getIntegerSCEV(0, V->getType());
-  else if (isa<UndefValue>(V))
-    return getIntegerSCEV(0, V->getType());
   else if (GlobalAlias *GA = dyn_cast<GlobalAlias>(V))
     return GA->mayBeOverridden() ? getUnknown(V) : getSCEV(GA->getAliasee());
   else

Modified: llvm/branches/Apple/Morbo/lib/Analysis/ScalarEvolutionExpander.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Morbo/lib/Analysis/ScalarEvolutionExpander.cpp?rev=101103&r1=101102&r2=101103&view=diff
==============================================================================
--- llvm/branches/Apple/Morbo/lib/Analysis/ScalarEvolutionExpander.cpp (original)
+++ llvm/branches/Apple/Morbo/lib/Analysis/ScalarEvolutionExpander.cpp Mon Apr 12 19:21:38 2010
@@ -705,9 +705,11 @@
       Sum = expandAddToGEP(NewOps.begin(), NewOps.end(), PTy, Ty, Sum);
     } else if (const PointerType *PTy = dyn_cast<PointerType>(Op->getType())) {
       // The running sum is an integer, and there's a pointer at this level.
-      // Try to form a getelementptr.
+      // Try to form a getelementptr. If the running sum is instructions,
+      // use a SCEVUnknown to avoid re-analyzing them.
       SmallVector<const SCEV *, 4> NewOps;
-      NewOps.push_back(SE.getUnknown(Sum));
+      NewOps.push_back(isa<Instruction>(Sum) ? SE.getUnknown(Sum) :
+                                               SE.getSCEV(Sum));
       for (++I; I != E && I->first == CurLoop; ++I)
         NewOps.push_back(I->second);
       Sum = expandAddToGEP(NewOps.begin(), NewOps.end(), PTy, Ty, expand(Op));
@@ -966,9 +968,12 @@
   // Determine a normalized form of this expression, which is the expression
   // before any post-inc adjustment is made.
   const SCEVAddRecExpr *Normalized = S;
-  if (L == PostIncLoop) {
-    const SCEV *Step = S->getStepRecurrence(SE);
-    Normalized = cast<SCEVAddRecExpr>(SE.getMinusSCEV(S, Step));
+  if (PostIncLoops.count(L)) {
+    PostIncLoopSet Loops;
+    Loops.insert(L);
+    Normalized =
+      cast<SCEVAddRecExpr>(TransformForPostIncUse(Normalize, S, 0, 0,
+                                                  Loops, SE, *SE.DT));
   }
 
   // Strip off any non-loop-dominating component from the addrec start.
@@ -1002,7 +1007,7 @@
 
   // Accommodate post-inc mode, if necessary.
   Value *Result;
-  if (L != PostIncLoop)
+  if (!PostIncLoops.count(L))
     Result = PN;
   else {
     // In PostInc mode, use the post-incremented value.
@@ -1274,7 +1279,7 @@
       // If the SCEV is computable at this level, insert it into the header
       // after the PHIs (and after any other instructions that we've inserted
       // there) so that it is guaranteed to dominate any user inside the loop.
-      if (L && S->hasComputableLoopEvolution(L) && L != PostIncLoop)
+      if (L && S->hasComputableLoopEvolution(L) && !PostIncLoops.count(L))
         InsertPt = L->getHeader()->getFirstNonPHI();
       while (isInsertedInstruction(InsertPt) || isa<DbgInfoIntrinsic>(InsertPt))
         InsertPt = llvm::next(BasicBlock::iterator(InsertPt));
@@ -1296,7 +1301,7 @@
   Value *V = visit(S);
 
   // Remember the expanded value for this SCEV at this location.
-  if (!PostIncLoop)
+  if (PostIncLoops.empty())
     InsertedExpressions[std::make_pair(S, InsertPt)] = V;
 
   restoreInsertPoint(SaveInsertBB, SaveInsertPt);
@@ -1304,7 +1309,7 @@
 }
 
 void SCEVExpander::rememberInstruction(Value *I) {
-  if (!PostIncLoop)
+  if (PostIncLoops.empty())
     InsertedValues.insert(I);
 
   // If we just claimed an existing instruction and that instruction had

Modified: llvm/branches/Apple/Morbo/lib/Transforms/Scalar/IndVarSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Morbo/lib/Transforms/Scalar/IndVarSimplify.cpp?rev=101103&r1=101102&r2=101103&view=diff
==============================================================================
--- llvm/branches/Apple/Morbo/lib/Transforms/Scalar/IndVarSimplify.cpp (original)
+++ llvm/branches/Apple/Morbo/lib/Transforms/Scalar/IndVarSimplify.cpp Mon Apr 12 19:21:38 2010
@@ -450,6 +450,46 @@
   return Changed;
 }
 
+// FIXME: It is an extremely bad idea to indvar substitute anything more
+// complex than affine induction variables.  Doing so will put expensive
+// polynomial evaluations inside of the loop, and the str reduction pass
+// currently can only reduce affine polynomials.  For now just disable
+// indvar subst on anything more complex than an affine addrec, unless
+// it can be expanded to a trivial value.
+static bool isSafe(const SCEV *S, const Loop *L) {
+  // Loop-invariant values are safe.
+  if (S->isLoopInvariant(L)) return true;
+
+  // Affine addrecs are safe. Non-affine are not, because LSR doesn't know how
+  // to transform them into efficient code.
+  if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S))
+    return AR->isAffine();
+
+  // An add is safe it all its operands are safe.
+  if (const SCEVCommutativeExpr *Commutative = dyn_cast<SCEVCommutativeExpr>(S)) {
+    for (SCEVCommutativeExpr::op_iterator I = Commutative->op_begin(),
+         E = Commutative->op_end(); I != E; ++I)
+      if (!isSafe(*I, L)) return false;
+    return true;
+  }
+  
+  // A cast is safe if its operand is.
+  if (const SCEVCastExpr *C = dyn_cast<SCEVCastExpr>(S))
+    return isSafe(C->getOperand(), L);
+
+  // A udiv is safe if its operands are.
+  if (const SCEVUDivExpr *UD = dyn_cast<SCEVUDivExpr>(S))
+    return isSafe(UD->getLHS(), L) &&
+           isSafe(UD->getRHS(), L);
+
+  // SCEVUnknown is always safe.
+  if (isa<SCEVUnknown>(S))
+    return true;
+
+  // Nothing else is safe.
+  return false;
+}
+
 void IndVarSimplify::RewriteIVExpressions(Loop *L, SCEVExpander &Rewriter) {
   SmallVector<WeakVH, 16> DeadInsts;
 
@@ -461,7 +501,6 @@
   // the need for the code evaluation methods to insert induction variables
   // of different sizes.
   for (IVUsers::iterator UI = IU->begin(), E = IU->end(); UI != E; ++UI) {
-    const SCEV *Stride = UI->getStride();
     Value *Op = UI->getOperandValToReplace();
     const Type *UseTy = Op->getType();
     Instruction *User = UI->getUser();
@@ -482,7 +521,7 @@
     // currently can only reduce affine polynomials.  For now just disable
     // indvar subst on anything more complex than an affine addrec, unless
     // it can be expanded to a trivial value.
-    if (!AR->isLoopInvariant(L) && !Stride->isLoopInvariant(L))
+    if (!isSafe(AR, L))
       continue;
 
     // Determine the insertion point for this user. By default, insert

Modified: llvm/branches/Apple/Morbo/lib/Transforms/Scalar/LoopStrengthReduce.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Morbo/lib/Transforms/Scalar/LoopStrengthReduce.cpp?rev=101103&r1=101102&r2=101103&view=diff
==============================================================================
--- llvm/branches/Apple/Morbo/lib/Transforms/Scalar/LoopStrengthReduce.cpp (original)
+++ llvm/branches/Apple/Morbo/lib/Transforms/Scalar/LoopStrengthReduce.cpp Mon Apr 12 19:21:38 2010
@@ -262,11 +262,15 @@
   SmallVector<const SCEV *, 4> Bad;
   DoInitialMatch(S, L, Good, Bad, SE, DT);
   if (!Good.empty()) {
-    BaseRegs.push_back(SE.getAddExpr(Good));
+    const SCEV *Sum = SE.getAddExpr(Good);
+    if (!Sum->isZero())
+      BaseRegs.push_back(Sum);
     AM.HasBaseReg = true;
   }
   if (!Bad.empty()) {
-    BaseRegs.push_back(SE.getAddExpr(Bad));
+    const SCEV *Sum = SE.getAddExpr(Bad);
+    if (!Sum->isZero())
+      BaseRegs.push_back(Sum);
     AM.HasBaseReg = true;
   }
 }
@@ -781,10 +785,10 @@
   /// will be replaced.
   Value *OperandValToReplace;
 
-  /// PostIncLoop - If this user is to use the post-incremented value of an
+  /// PostIncLoops - If this user is to use the post-incremented value of an
   /// induction variable, this variable is non-null and holds the loop
   /// associated with the induction variable.
-  const Loop *PostIncLoop;
+  PostIncLoopSet PostIncLoops;
 
   /// LUIdx - The index of the LSRUse describing the expression which
   /// this fixup needs, minus an offset (below).
@@ -795,6 +799,8 @@
   /// offsets, for example in an unrolled loop.
   int64_t Offset;
 
+  bool isUseFullyOutsideLoop(const Loop *L) const;
+
   LSRFixup();
 
   void print(raw_ostream &OS) const;
@@ -804,9 +810,24 @@
 }
 
 LSRFixup::LSRFixup()
-  : UserInst(0), OperandValToReplace(0), PostIncLoop(0),
+  : UserInst(0), OperandValToReplace(0),
     LUIdx(~size_t(0)), Offset(0) {}
 
+/// isUseFullyOutsideLoop - Test whether this fixup always uses its
+/// value outside of the given loop.
+bool LSRFixup::isUseFullyOutsideLoop(const Loop *L) const {
+  // PHI nodes use their value in their incoming blocks.
+  if (const PHINode *PN = dyn_cast<PHINode>(UserInst)) {
+    for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
+      if (PN->getIncomingValue(i) == OperandValToReplace &&
+          L->contains(PN->getIncomingBlock(i)))
+        return false;
+    return true;
+  }
+
+  return !L->contains(UserInst);
+}
+
 void LSRFixup::print(raw_ostream &OS) const {
   OS << "UserInst=";
   // Store is common and interesting enough to be worth special-casing.
@@ -821,9 +842,10 @@
   OS << ", OperandValToReplace=";
   WriteAsOperand(OS, OperandValToReplace, /*PrintType=*/false);
 
-  if (PostIncLoop) {
+  for (PostIncLoopSet::const_iterator I = PostIncLoops.begin(),
+       E = PostIncLoops.end(); I != E; ++I) {
     OS << ", PostIncLoop=";
-    WriteAsOperand(OS, PostIncLoop->getHeader(), /*PrintType=*/false);
+    WriteAsOperand(OS, (*I)->getHeader(), /*PrintType=*/false);
   }
 
   if (LUIdx != ~size_t(0))
@@ -1135,6 +1157,7 @@
   IVUsers &IU;
   ScalarEvolution &SE;
   DominatorTree &DT;
+  LoopInfo &LI;
   const TargetLowering *const TLI;
   Loop *const L;
   bool Changed;
@@ -1214,6 +1237,13 @@
                     DenseSet<const SCEV *> &VisitedRegs) const;
   void Solve(SmallVectorImpl<const Formula *> &Solution) const;
 
+  BasicBlock::iterator
+    HoistInsertPosition(BasicBlock::iterator IP,
+                        const SmallVectorImpl<Instruction *> &Inputs) const;
+  BasicBlock::iterator AdjustInsertPositionForExpand(BasicBlock::iterator IP,
+                                                     const LSRFixup &LF,
+                                                     const LSRUse &LU) const;
+
   Value *Expand(const LSRFixup &LF,
                 const Formula &F,
                 BasicBlock::iterator IP,
@@ -1545,8 +1575,9 @@
             !DT.properlyDominates(UI->getUser()->getParent(), ExitingBlock)) {
           // Conservatively assume there may be reuse if the quotient of their
           // strides could be a legal scale.
-          const SCEV *A = CondUse->getStride();
-          const SCEV *B = UI->getStride();
+          const SCEV *A = CondUse->getStride(L);
+          const SCEV *B = UI->getStride(L);
+          if (!A || !B) continue;
           if (SE.getTypeSizeInBits(A->getType()) !=
               SE.getTypeSizeInBits(B->getType())) {
             if (SE.getTypeSizeInBits(A->getType()) >
@@ -1598,7 +1629,7 @@
         ExitingBlock->getInstList().insert(TermBr, Cond);
 
         // Clone the IVUse, as the old use still exists!
-        CondUse = &IU.AddUser(CondUse->getStride(), CondUse->getOffset(),
+        CondUse = &IU.AddUser(CondUse->getExpr(),
                               Cond, CondUse->getOperandValToReplace());
         TermBr->replaceUsesOfWith(OldCond, Cond);
       }
@@ -1607,9 +1638,7 @@
     // If we get to here, we know that we can transform the setcc instruction to
     // use the post-incremented version of the IV, allowing us to coalesce the
     // live ranges for the IV correctly.
-    CondUse->setOffset(SE.getMinusSCEV(CondUse->getOffset(),
-                                       CondUse->getStride()));
-    CondUse->setIsUseOfPostIncrementedValue(true);
+    CondUse->transformToPostInc(L);
     Changed = true;
 
     PostIncs.insert(Cond);
@@ -1717,19 +1746,24 @@
   SmallSetVector<const SCEV *, 4> Strides;
 
   // Collect interesting types and strides.
+  SmallVector<const SCEV *, 4> Worklist;
   for (IVUsers::const_iterator UI = IU.begin(), E = IU.end(); UI != E; ++UI) {
-    const SCEV *Stride = UI->getStride();
+    const SCEV *Expr = UI->getExpr();
 
     // Collect interesting types.
-    Types.insert(SE.getEffectiveSCEVType(Stride->getType()));
-
-    // Add the stride for this loop.
-    Strides.insert(Stride);
+    Types.insert(SE.getEffectiveSCEVType(Expr->getType()));
 
-    // Add strides for other mentioned loops.
-    for (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(UI->getOffset());
-         AR; AR = dyn_cast<SCEVAddRecExpr>(AR->getStart()))
-      Strides.insert(AR->getStepRecurrence(SE));
+    // Add strides for mentioned loops.
+    Worklist.push_back(Expr);
+    do {
+      const SCEV *S = Worklist.pop_back_val();
+      if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
+        Strides.insert(AR->getStepRecurrence(SE));
+        Worklist.push_back(AR->getStart());
+      } else if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
+        Worklist.insert(Worklist.end(), Add->op_begin(), Add->op_end());
+      }
+    } while (!Worklist.empty());
   }
 
   // Compute interesting factors from the set of interesting strides.
@@ -1776,8 +1810,7 @@
     LSRFixup &LF = getNewFixup();
     LF.UserInst = UI->getUser();
     LF.OperandValToReplace = UI->getOperandValToReplace();
-    if (UI->isUseOfPostIncrementedValue())
-      LF.PostIncLoop = L;
+    LF.PostIncLoops = UI->getPostIncLoops();
 
     LSRUse::KindType Kind = LSRUse::Basic;
     const Type *AccessTy = 0;
@@ -1786,7 +1819,7 @@
       AccessTy = getAccessType(LF.UserInst);
     }
 
-    const SCEV *S = IU.getCanonicalExpr(*UI);
+    const SCEV *S = UI->getExpr();
 
     // Equality (== and !=) ICmps are special. We can rewrite (i == N) as
     // (N - i == 0), and this allows (N - i) to be the expression that we work
@@ -1824,7 +1857,7 @@
     LF.LUIdx = P.first;
     LF.Offset = P.second;
     LSRUse &LU = Uses[LF.LUIdx];
-    LU.AllFixupsOutsideLoop &= !L->contains(LF.UserInst);
+    LU.AllFixupsOutsideLoop &= LF.isUseFullyOutsideLoop(L);
 
     // If this is the first use of this LSRUse, give it a formula.
     if (LU.Formulae.empty()) {
@@ -1918,9 +1951,17 @@
           continue;
         // Ignore uses which are part of other SCEV expressions, to avoid
         // analyzing them multiple times.
-        if (SE.isSCEVable(UserInst->getType()) &&
-            !isa<SCEVUnknown>(SE.getSCEV(const_cast<Instruction *>(UserInst))))
-          continue;
+        if (SE.isSCEVable(UserInst->getType())) {
+          const SCEV *UserS = SE.getSCEV(const_cast<Instruction *>(UserInst));
+          // If the user is a no-op, look through to its uses.
+          if (!isa<SCEVUnknown>(UserS))
+            continue;
+          if (UserS == U) {
+            Worklist.push_back(
+              SE.getUnknown(const_cast<Instruction *>(UserInst)));
+            continue;
+          }
+        }
         // Ignore icmp instructions which are already being analyzed.
         if (const ICmpInst *ICI = dyn_cast<ICmpInst>(UserInst)) {
           unsigned OtherIdx = !UI.getOperandNo();
@@ -1936,7 +1977,7 @@
         LF.LUIdx = P.first;
         LF.Offset = P.second;
         LSRUse &LU = Uses[LF.LUIdx];
-        LU.AllFixupsOutsideLoop &= L->contains(LF.UserInst);
+        LU.AllFixupsOutsideLoop &= LF.isUseFullyOutsideLoop(L);
         InsertSupplementalFormula(U, LU, LF.LUIdx);
         CountRegisters(LU.Formulae.back(), Uses.size() - 1);
         break;
@@ -2776,37 +2817,33 @@
   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];
+/// HoistInsertPosition - Helper for AdjustInsertPositionForExpand. Climb up
+/// the dominator tree far as we can go while still being dominated by the
+/// input positions. This helps canonicalize the insert position, which
+/// encourages sharing.
+BasicBlock::iterator
+LSRInstance::HoistInsertPosition(BasicBlock::iterator IP,
+                                 const SmallVectorImpl<Instruction *> &Inputs)
+                                                                         const {
+  for (;;) {
+    const Loop *IPLoop = LI.getLoopFor(IP->getParent());
+    unsigned IPLoopDepth = IPLoop ? IPLoop->getLoopDepth() : 0;
 
-  // Then, collect some instructions which we will remain dominated by when
-  // expanding the replacement. These must be dominated by any operands that
-  // will be required in the expansion.
-  SmallVector<Instruction *, 4> Inputs;
-  if (Instruction *I = dyn_cast<Instruction>(LF.OperandValToReplace))
-    Inputs.push_back(I);
-  if (LU.Kind == LSRUse::ICmpZero)
-    if (Instruction *I =
-          dyn_cast<Instruction>(cast<ICmpInst>(LF.UserInst)->getOperand(1)))
-      Inputs.push_back(I);
-  if (LF.PostIncLoop) {
-    if (!L->contains(LF.UserInst))
-      Inputs.push_back(L->getLoopLatch()->getTerminator());
-    else
-      Inputs.push_back(IVIncInsertPos);
-  }
+    BasicBlock *IDom;
+    for (BasicBlock *Rung = IP->getParent(); ; Rung = IDom) {
+      IDom = getImmediateDominator(Rung, DT);
+      if (!IDom) return IP;
+
+      // Don't climb into a loop though.
+      const Loop *IDomLoop = LI.getLoopFor(IDom);
+      unsigned IDomDepth = IDomLoop ? IDomLoop->getLoopDepth() : 0;
+      if (IDomDepth <= IPLoopDepth &&
+          (IDomDepth != IPLoopDepth || IDomLoop == IPLoop))
+        break;
+    }
 
-  // Then, climb up the immediate dominator tree as far as we can go while
-  // still being dominated by the input positions.
-  for (;;) {
     bool AllDominate = true;
     Instruction *BetterPos = 0;
-    BasicBlock *IDom = getImmediateDominator(IP->getParent(), DT);
-    if (!IDom) break;
     Instruction *Tentative = IDom->getTerminator();
     for (SmallVectorImpl<Instruction *>::const_iterator I = Inputs.begin(),
          E = Inputs.end(); I != E; ++I) {
@@ -2815,6 +2852,8 @@
         AllDominate = false;
         break;
       }
+      // Attempt to find an insert position in the middle of the block,
+      // instead of at the end, so that it can be used for other expansions.
       if (IDom == Inst->getParent() &&
           (!BetterPos || DT.dominates(BetterPos, Inst)))
         BetterPos = next(BasicBlock::iterator(Inst));
@@ -2826,12 +2865,77 @@
     else
       IP = Tentative;
   }
+
+  return IP;
+}
+
+/// AdjustInsertPositionForExpand - Determine an input position which will be
+/// dominated by the operands and which will dominate the result.
+BasicBlock::iterator
+LSRInstance::AdjustInsertPositionForExpand(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;
+  if (Instruction *I = dyn_cast<Instruction>(LF.OperandValToReplace))
+    Inputs.push_back(I);
+  if (LU.Kind == LSRUse::ICmpZero)
+    if (Instruction *I =
+          dyn_cast<Instruction>(cast<ICmpInst>(LF.UserInst)->getOperand(1)))
+      Inputs.push_back(I);
+  if (LF.PostIncLoops.count(L)) {
+    if (LF.isUseFullyOutsideLoop(L))
+      Inputs.push_back(L->getLoopLatch()->getTerminator());
+    else
+      Inputs.push_back(IVIncInsertPos);
+  }
+  // The expansion must also be dominated by the increment positions of any
+  // loops it for which it is using post-inc mode.
+  for (PostIncLoopSet::const_iterator I = LF.PostIncLoops.begin(),
+       E = LF.PostIncLoops.end(); I != E; ++I) {
+    const Loop *PIL = *I;
+    if (PIL == L) continue;
+
+    // Be dominated by the loop exit.
+    SmallVector<BasicBlock *, 4> ExitingBlocks;
+    PIL->getExitingBlocks(ExitingBlocks);
+    if (!ExitingBlocks.empty()) {
+      BasicBlock *BB = ExitingBlocks[0];
+      for (unsigned i = 1, e = ExitingBlocks.size(); i != e; ++i)
+        BB = DT.findNearestCommonDominator(BB, ExitingBlocks[i]);
+      Inputs.push_back(BB->getTerminator());
+    }
+  }
+
+  // Then, climb up the immediate dominator tree as far as we can go while
+  // still being dominated by the input positions.
+  IP = HoistInsertPosition(IP, Inputs);
+
+  // 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 = AdjustInsertPositionForExpand(IP, LF, LU);
+
   // Inform the Rewriter if we have a post-increment use, so that it can
   // perform an advantageous expansion.
-  Rewriter.setPostInc(LF.PostIncLoop);
+  Rewriter.setPostInc(LF.PostIncLoops);
 
   // This is the type that the user actually needs.
   const Type *OpTy = LF.OperandValToReplace->getType();
@@ -2855,24 +2959,11 @@
     const SCEV *Reg = *I;
     assert(!Reg->isZero() && "Zero allocated in a base register!");
 
-    // If we're expanding for a post-inc user for the add-rec's loop, make the
-    // post-inc adjustment.
-    const SCEV *Start = Reg;
-    while (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Start)) {
-      if (AR->getLoop() == LF.PostIncLoop) {
-        Reg = SE.getAddExpr(Reg, AR->getStepRecurrence(SE));
-        // If the user is inside the loop, insert the code after the increment
-        // so that it is dominated by its operand. If the original insert point
-        // was already dominated by the increment, keep it, because there may
-        // be loop-variant operands that need to be respected also.
-        if (L->contains(LF.UserInst) && !DT.dominates(IVIncInsertPos, IP)) {
-          IP = IVIncInsertPos;
-          while (isa<DbgInfoIntrinsic>(IP)) ++IP;
-        }
-        break;
-      }
-      Start = AR->getStart();
-    }
+    // If we're expanding for a post-inc user, make the post-inc adjustment.
+    PostIncLoopSet &Loops = const_cast<PostIncLoopSet &>(LF.PostIncLoops);
+    Reg = TransformForPostIncUse(Denormalize, Reg,
+                                 LF.UserInst, LF.OperandValToReplace,
+                                 Loops, SE, DT);
 
     Ops.push_back(SE.getUnknown(Rewriter.expandCodeFor(Reg, 0, IP)));
   }
@@ -2889,11 +2980,11 @@
   if (F.AM.Scale != 0) {
     const SCEV *ScaledS = F.ScaledReg;
 
-    // If we're expanding for a post-inc user for the add-rec's loop, make the
-    // post-inc adjustment.
-    if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(ScaledS))
-      if (AR->getLoop() == LF.PostIncLoop)
-        ScaledS = SE.getAddExpr(ScaledS, AR->getStepRecurrence(SE));
+    // If we're expanding for a post-inc user, make the post-inc adjustment.
+    PostIncLoopSet &Loops = const_cast<PostIncLoopSet &>(LF.PostIncLoops);
+    ScaledS = TransformForPostIncUse(Denormalize, ScaledS,
+                                     LF.UserInst, LF.OperandValToReplace,
+                                     Loops, SE, DT);
 
     if (LU.Kind == LSRUse::ICmpZero) {
       // An interesting way of "folding" with an icmp is to use a negated
@@ -2954,7 +3045,7 @@
   Value *FullV = Rewriter.expandCodeFor(FullS, Ty, IP);
 
   // We're done expanding now, so reset the rewriter.
-  Rewriter.setPostInc(0);
+  Rewriter.clearPostInc();
 
   // An ICmpZero Formula represents an ICmp which we're handling as a
   // comparison against zero. Now that we've expanded an expression for that
@@ -3118,6 +3209,7 @@
   : IU(P->getAnalysis<IVUsers>()),
     SE(P->getAnalysis<ScalarEvolution>()),
     DT(P->getAnalysis<DominatorTree>()),
+    LI(P->getAnalysis<LoopInfo>()),
     TLI(tli), L(l), Changed(false), IVIncInsertPos(0) {
 
   // If LoopSimplify form is not available, stay out of trouble.
@@ -3274,9 +3366,10 @@
   // We split critical edges, so we change the CFG.  However, we do update
   // many analyses if they are around.
   AU.addPreservedID(LoopSimplifyID);
-  AU.addPreserved<LoopInfo>();
   AU.addPreserved("domfrontier");
 
+  AU.addRequired<LoopInfo>();
+  AU.addPreserved<LoopInfo>();
   AU.addRequiredID(LoopSimplifyID);
   AU.addRequired<DominatorTree>();
   AU.addPreserved<DominatorTree>();

Copied: llvm/branches/Apple/Morbo/test/CodeGen/X86/multiple-loop-post-inc.ll (from r100699, llvm/trunk/test/CodeGen/X86/multiple-loop-post-inc.ll)
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Morbo/test/CodeGen/X86/multiple-loop-post-inc.ll?p2=llvm/branches/Apple/Morbo/test/CodeGen/X86/multiple-loop-post-inc.ll&p1=llvm/trunk/test/CodeGen/X86/multiple-loop-post-inc.ll&r1=100699&r2=101103&rev=101103&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/multiple-loop-post-inc.ll (original)
+++ llvm/branches/Apple/Morbo/test/CodeGen/X86/multiple-loop-post-inc.ll Mon Apr 12 19:21:38 2010
@@ -275,3 +275,30 @@
 return:                                           ; preds = %entry
   ret void
 }
+
+; Codegen shouldn't crash on this testcase.
+
+define void @bar(i32 %a, i32 %b) nounwind {
+entry:                           ; preds = %bb1, %entry, %for.end204
+  br label %outer
+
+outer:                                     ; preds = %bb1, %entry
+  %i6 = phi i32 [ %storemerge171, %bb1 ], [ %a, %entry ] ; <i32> [#uses=2]
+  %storemerge171 = add i32 %i6, 1      ; <i32> [#uses=1]
+  br label %inner
+
+inner:                                       ; preds = %bb0, %if.end275
+  %i8 = phi i32 [ %a, %outer ], [ %indvar.next159, %bb0 ] ; <i32> [#uses=2]
+  %t338 = load i32* undef                     ; <i32> [#uses=1]
+  %t191 = mul i32 %i8, %t338        ; <i32> [#uses=1]
+  %t179 = add i32 %i6, %t191        ; <i32> [#uses=1]
+  br label %bb0
+
+bb0:                                     ; preds = %for.body332
+  %indvar.next159 = add i32 %i8, 1     ; <i32> [#uses=1]
+  br i1 undef, label %bb1, label %inner
+
+bb1:                                     ; preds = %bb0, %outer
+  %midx.4 = phi i32 [ %t179, %bb0 ] ; <i32> [#uses=0]
+  br label %outer
+}

Modified: llvm/branches/Apple/Morbo/test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Morbo/test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll?rev=101103&r1=101102&r2=101103&view=diff
==============================================================================
--- llvm/branches/Apple/Morbo/test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll (original)
+++ llvm/branches/Apple/Morbo/test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll Mon Apr 12 19:21:38 2010
@@ -1,4 +1,4 @@
-; RUN: opt < %s -analyze -iv-users | grep {\{1,+,3,+,2\}<%loop> (post-inc)}
+; RUN: opt < %s -analyze -iv-users | grep {\{1,+,3,+,2\}<%loop> (post-inc with loop %loop)}
 
 ; The value of %r is dependent on a polynomial iteration expression.
 

Copied: llvm/branches/Apple/Morbo/test/Transforms/LoopStrengthReduce/uglygep.ll (from r100884, llvm/trunk/test/Transforms/LoopStrengthReduce/uglygep.ll)
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/Apple/Morbo/test/Transforms/LoopStrengthReduce/uglygep.ll?p2=llvm/branches/Apple/Morbo/test/Transforms/LoopStrengthReduce/uglygep.ll&p1=llvm/trunk/test/Transforms/LoopStrengthReduce/uglygep.ll&r1=100884&r2=101103&rev=101103&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopStrengthReduce/uglygep.ll (original)
+++ llvm/branches/Apple/Morbo/test/Transforms/LoopStrengthReduce/uglygep.ll Mon Apr 12 19:21:38 2010
@@ -35,3 +35,33 @@
   store i8 undef, i8* %t9
   br label %bb14
 }
+
+define fastcc void @TransformLine() nounwind {
+bb:
+  br label %loop0
+
+loop0:                                            ; preds = %loop0, %bb
+  %i0 = phi i32 [ %i0.next, %loop0 ], [ 0, %bb ]  ; <i32> [#uses=2]
+  %i0.next = add i32 %i0, 1                       ; <i32> [#uses=1]
+  br i1 false, label %loop0, label %bb0
+
+bb0:                                              ; preds = %loop0
+  br label %loop1
+
+loop1:                                            ; preds = %bb5, %bb0
+  %i1 = phi i32 [ 0, %bb0 ], [ %i1.next, %bb5 ]   ; <i32> [#uses=4]
+  %t0 = add i32 %i0, %i1                          ; <i32> [#uses=1]
+  br i1 false, label %bb2, label %bb6
+
+bb2:                                              ; preds = %loop1
+  br i1 true, label %bb6, label %bb5
+
+bb5:                                              ; preds = %bb2
+  %i1.next = add i32 %i1, 1                       ; <i32> [#uses=1]
+  br i1 true, label %bb6, label %loop1
+
+bb6:                                              ; preds = %bb5, %bb2, %loop1
+  %p8 = phi i32 [ %t0, %bb5 ], [ undef, %loop1 ], [ undef, %bb2 ] ; <i32> [#uses=0]
+  %p9 = phi i32 [ undef, %bb5 ], [ %i1, %loop1 ], [ %i1, %bb2 ] ; <i32> [#uses=0]
+  unreachable
+}





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