[llvm-commits] [llvm] r73293 - in /llvm/trunk: include/llvm/Analysis/ScalarEvolution.h lib/Analysis/ScalarEvolution.cpp

[Dan Gohman]

Author: djg
Date: Sat Jun 13 10:56:47 2009
New Revision: 73293

URL: http://llvm.org/viewvc/llvm-project?rev=73293&view=rev
Log:
Add a ScalarEvolution::getAnyExtendExpr utility function for performing
extension with unspecified bits.

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

Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolution.h?rev=73293&r1=73292&r2=73293&view=diff

==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolution.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolution.h Sat Jun 13 10:56:47 2009
@@ -393,6 +393,7 @@
     SCEVHandle getTruncateExpr(const SCEVHandle &Op, const Type *Ty);
     SCEVHandle getZeroExtendExpr(const SCEVHandle &Op, const Type *Ty);
     SCEVHandle getSignExtendExpr(const SCEVHandle &Op, const Type *Ty);
+    SCEVHandle getAnyExtendExpr(const SCEVHandle &Op, const Type *Ty);
     SCEVHandle getAddExpr(std::vector<SCEVHandle> &Ops);
     SCEVHandle getAddExpr(const SCEVHandle &LHS, const SCEVHandle &RHS) {
       std::vector<SCEVHandle> Ops;
@@ -465,6 +466,12 @@
     /// it is sign extended.  The conversion must not be narrowing.
     SCEVHandle getNoopOrSignExtend(const SCEVHandle &V, const Type *Ty);
 
+    /// getNoopOrAnyExtend - Return a SCEV corresponding to a conversion of
+    /// the input value to the specified type. If the type must be extended,
+    /// it is extended with unspecified bits. The conversion must not be
+    /// narrowing.
+    SCEVHandle getNoopOrAnyExtend(const SCEVHandle &V, const Type *Ty);
+
     /// getTruncateOrNoop - Return a SCEV corresponding to a conversion of the
     /// input value to the specified type.  The conversion must not be
     /// widening.

Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=73293&r1=73292&r2=73293&view=diff

==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Sat Jun 13 10:56:47 2009
@@ -937,6 +937,48 @@
   return Result;
 }
 
+/// getAnyExtendExpr - Return a SCEV for the given operand extended with
+/// unspecified bits out to the given type.
+///
+SCEVHandle ScalarEvolution::getAnyExtendExpr(const SCEVHandle &Op,
+                                             const Type *Ty) {
+  assert(getTypeSizeInBits(Op->getType()) < getTypeSizeInBits(Ty) &&
+         "This is not an extending conversion!");
+  assert(isSCEVable(Ty) &&
+         "This is not a conversion to a SCEVable type!");
+  Ty = getEffectiveSCEVType(Ty);
+
+  // Sign-extend negative constants.
+  if (const SCEVConstant *SC = dyn_cast<SCEVConstant>(Op))
+    if (SC->getValue()->getValue().isNegative())
+      return getSignExtendExpr(Op, Ty);
+
+  // Peel off a truncate cast.
+  if (const SCEVTruncateExpr *T = dyn_cast<SCEVTruncateExpr>(Op)) {
+    SCEVHandle NewOp = T->getOperand();
+    if (getTypeSizeInBits(NewOp->getType()) < getTypeSizeInBits(Ty))
+      return getAnyExtendExpr(NewOp, Ty);
+    return getTruncateOrNoop(NewOp, Ty);
+  }
+
+  // Next try a zext cast. If the cast is folded, use it.
+  SCEVHandle ZExt = getZeroExtendExpr(Op, Ty);
+  if (!isa<SCEVZeroExtendExpr>(ZExt))
+    return ZExt;
+
+  // Next try a sext cast. If the cast is folded, use it.
+  SCEVHandle SExt = getSignExtendExpr(Op, Ty);
+  if (!isa<SCEVSignExtendExpr>(SExt))
+    return SExt;
+
+  // If the expression is obviously signed, use the sext cast value.
+  if (isa<SCEVSMaxExpr>(Op))
+    return SExt;
+
+  // Absent any other information, use the zext cast value.
+  return ZExt;
+}
+
 /// getAddExpr - Get a canonical add expression, or something simpler if
 /// possible.
 SCEVHandle ScalarEvolution::getAddExpr(std::vector<SCEVHandle> &Ops) {
@@ -1903,6 +1945,23 @@
   return getSignExtendExpr(V, Ty);
 }
 
+/// getNoopOrAnyExtend - Return a SCEV corresponding to a conversion of
+/// the input value to the specified type. If the type must be extended,
+/// it is extended with unspecified bits. The conversion must not be
+/// narrowing.
+SCEVHandle
+ScalarEvolution::getNoopOrAnyExtend(const SCEVHandle &V, const Type *Ty) {
+  const Type *SrcTy = V->getType();
+  assert((SrcTy->isInteger() || (TD && isa<PointerType>(SrcTy))) &&
+         (Ty->isInteger() || (TD && isa<PointerType>(Ty))) &&
+         "Cannot noop or any extend with non-integer arguments!");
+  assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
+         "getNoopOrAnyExtend cannot truncate!");
+  if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
+    return V;  // No conversion
+  return getAnyExtendExpr(V, Ty);
+}
+
 /// getTruncateOrNoop - Return a SCEV corresponding to a conversion of the
 /// input value to the specified type.  The conversion must not be widening.
 SCEVHandle