Add three new helper routines, getNoopOrZeroExtend,

getNoopOrSignExtend, and getTruncateOrNoop. These are similar
to getTruncateOrZeroExtend etc., except that they assert that
the conversion is either not widening or narrowing, as
appropriate. These will be used in some upcoming fixes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71632 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 47 insertions, 0 deletions

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index a71db86..77a8070 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -1807,6 +1807,53 @@ ScalarEvolution::getTruncateOrSignExtend(const SCEVHandle &V,
   return getSignExtendExpr(V, Ty);
 }
 
+/// getNoopOrZeroExtend - Return a SCEV corresponding to a conversion of the
+/// input value to the specified type.  If the type must be extended, it is zero
+/// extended.  The conversion must not be narrowing.
+SCEVHandle
+ScalarEvolution::getNoopOrZeroExtend(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 zero extend with non-integer arguments!");
+  assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
+         "getNoopOrZeroExtend cannot truncate!");
+  if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
+    return V;  // No conversion
+  return getZeroExtendExpr(V, Ty);
+}
+
+/// getNoopOrSignExtend - Return a SCEV corresponding to a conversion of the
+/// input value to the specified type.  If the type must be extended, it is sign
+/// extended.  The conversion must not be narrowing.
+SCEVHandle
+ScalarEvolution::getNoopOrSignExtend(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 sign extend with non-integer arguments!");
+  assert(getTypeSizeInBits(SrcTy) <= getTypeSizeInBits(Ty) &&
+         "getNoopOrSignExtend cannot truncate!");
+  if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
+    return V;  // No conversion
+  return getSignExtendExpr(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
+ScalarEvolution::getTruncateOrNoop(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 truncate or noop with non-integer arguments!");
+  assert(getTypeSizeInBits(SrcTy) >= getTypeSizeInBits(Ty) &&
+         "getTruncateOrNoop cannot extend!");
+  if (getTypeSizeInBits(SrcTy) == getTypeSizeInBits(Ty))
+    return V;  // No conversion
+  return getTruncateExpr(V, Ty);
+}
+
 /// ReplaceSymbolicValueWithConcrete - This looks up the computed SCEV value for
 /// the specified instruction and replaces any references to the symbolic value
 /// SymName with the specified value.  This is used during PHI resolution.