[llvm-commits] [llvm] r157672 - /llvm/trunk/lib/Analysis/ScalarEvolution.cpp

[Andrew Trick]

Author: atrick
Date: Tue May 29 22:35:17 2012
New Revision: 157672

URL: http://llvm.org/viewvc/llvm-project?rev=157672&view=rev
Log:
Reformat the loop that does AddRecExpr * AddRecExpr reduction.

No functionality.

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=157672&r1=157671&r2=157672&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Tue May 29 22:35:17 2012
@@ -2037,63 +2037,64 @@
     for (unsigned OtherIdx = Idx+1;
          OtherIdx < Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
          ++OtherIdx) {
-      if (AddRecLoop == cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()) {
-        // {A1,+,A2,+,...,+,An}<L> * {B1,+,B2,+,...,+,Bn}<L>
-        // = {x=1 in [ sum y=x..2x [ sum z=max(y-x, y-n)..min(x,n) [
-        //       choose(x, 2x)*choose(2x-y, x-z)*A_{y-z}*B_z
-        //   ]]],+,...up to x=2n}.
-        // Note that the arguments to choose() are always integers with values
-        // known at compile time, never SCEV objects.
-        //
-        // The implementation avoids pointless extra computations when the two
-        // addrec's are of different length (mathematically, it's equivalent to
-        // an infinite stream of zeros on the right).
-        bool OpsModified = false;
-        for (; OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
-             ++OtherIdx)
-          if (const SCEVAddRecExpr *OtherAddRec =
-                dyn_cast<SCEVAddRecExpr>(Ops[OtherIdx]))
-            if (OtherAddRec->getLoop() == AddRecLoop) {
-              bool Overflow = false;
-              Type *Ty = AddRec->getType();
-              bool LargerThan64Bits = getTypeSizeInBits(Ty) > 64;
-              SmallVector<const SCEV*, 7> AddRecOps;
-              for (int x = 0, xe = AddRec->getNumOperands() +
-                     OtherAddRec->getNumOperands() - 1;
-                   x != xe && !Overflow; ++x) {
-                const SCEV *Term = getConstant(Ty, 0);
-                for (int y = x, ye = 2*x+1; y != ye && !Overflow; ++y) {
-                  uint64_t Coeff1 = Choose(x, 2*x - y, Overflow);
-                  for (int z = std::max(y-x, y-(int)AddRec->getNumOperands()+1),
-                         ze = std::min(x+1, (int)OtherAddRec->getNumOperands());
-                       z < ze && !Overflow; ++z) {
-                    uint64_t Coeff2 = Choose(2*x - y, x-z, Overflow);
-                    uint64_t Coeff;
-                    if (LargerThan64Bits)
-                      Coeff = umul_ov(Coeff1, Coeff2, Overflow);
-                    else
-                      Coeff = Coeff1*Coeff2;
-                    const SCEV *CoeffTerm = getConstant(Ty, Coeff);
-                    const SCEV *Term1 = AddRec->getOperand(y-z);
-                    const SCEV *Term2 = OtherAddRec->getOperand(z);
-                    Term = getAddExpr(Term, getMulExpr(CoeffTerm, Term1,Term2));
-                  }
-                }
-                AddRecOps.push_back(Term);
-              }
-              if (!Overflow) {
-                const SCEV *NewAddRec = getAddRecExpr(AddRecOps,
-                                                      AddRec->getLoop(),
-                                                      SCEV::FlagAnyWrap);
-                if (Ops.size() == 2) return NewAddRec;
-                Ops[Idx] = AddRec = cast<SCEVAddRecExpr>(NewAddRec);
-                Ops.erase(Ops.begin() + OtherIdx); --OtherIdx;
-                OpsModified = true;
-              }
+      if (AddRecLoop != cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop())
+        continue;
+
+      // {A1,+,A2,+,...,+,An}<L> * {B1,+,B2,+,...,+,Bn}<L>
+      // = {x=1 in [ sum y=x..2x [ sum z=max(y-x, y-n)..min(x,n) [
+      //       choose(x, 2x)*choose(2x-y, x-z)*A_{y-z}*B_z
+      //   ]]],+,...up to x=2n}.
+      // Note that the arguments to choose() are always integers with values
+      // known at compile time, never SCEV objects.
+      //
+      // The implementation avoids pointless extra computations when the two
+      // addrec's are of different length (mathematically, it's equivalent to
+      // an infinite stream of zeros on the right).
+      bool OpsModified = false;
+      for (; OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
+           ++OtherIdx) {
+        const SCEVAddRecExpr *OtherAddRec =
+          dyn_cast<SCEVAddRecExpr>(Ops[OtherIdx]);
+        if (!OtherAddRec || OtherAddRec->getLoop() != AddRecLoop)
+          continue;
+
+        bool Overflow = false;
+        Type *Ty = AddRec->getType();
+        bool LargerThan64Bits = getTypeSizeInBits(Ty) > 64;
+        SmallVector<const SCEV*, 7> AddRecOps;
+        for (int x = 0, xe = AddRec->getNumOperands() +
+               OtherAddRec->getNumOperands() - 1; x != xe && !Overflow; ++x) {
+          const SCEV *Term = getConstant(Ty, 0);
+          for (int y = x, ye = 2*x+1; y != ye && !Overflow; ++y) {
+            uint64_t Coeff1 = Choose(x, 2*x - y, Overflow);
+            for (int z = std::max(y-x, y-(int)AddRec->getNumOperands()+1),
+                   ze = std::min(x+1, (int)OtherAddRec->getNumOperands());
+                 z < ze && !Overflow; ++z) {
+              uint64_t Coeff2 = Choose(2*x - y, x-z, Overflow);
+              uint64_t Coeff;
+              if (LargerThan64Bits)
+                Coeff = umul_ov(Coeff1, Coeff2, Overflow);
+              else
+                Coeff = Coeff1*Coeff2;
+              const SCEV *CoeffTerm = getConstant(Ty, Coeff);
+              const SCEV *Term1 = AddRec->getOperand(y-z);
+              const SCEV *Term2 = OtherAddRec->getOperand(z);
+              Term = getAddExpr(Term, getMulExpr(CoeffTerm, Term1,Term2));
             }
-        if (OpsModified)
-          return getMulExpr(Ops);
+          }
+          AddRecOps.push_back(Term);
+        }
+        if (!Overflow) {
+          const SCEV *NewAddRec = getAddRecExpr(AddRecOps, AddRec->getLoop(),
+                                                SCEV::FlagAnyWrap);
+          if (Ops.size() == 2) return NewAddRec;
+          Ops[Idx] = AddRec = cast<SCEVAddRecExpr>(NewAddRec);
+          Ops.erase(Ops.begin() + OtherIdx); --OtherIdx;
+          OpsModified = true;
+        }
       }
+      if (OpsModified)
+        return getMulExpr(Ops);
     }
 
     // Otherwise couldn't fold anything into this recurrence.  Move onto the