From: Dan Gohman <gohman@apple.com>
Date: Wed, 13 May 2009 03:46:30 +0000 (+0000)
Subject: Add three new helper routines, getNoopOrZeroExtend,
X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=commitdiff_plain;h=467c430316b7a5b6fa8069531ca8d603b1e1197f

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
---

diff --git a/include/llvm/Analysis/ScalarEvolution.h b/include/llvm/Analysis/ScalarEvolution.h
index 37b1dc0ddd8..76e23b1169b 100644
--- a/include/llvm/Analysis/ScalarEvolution.h
+++ b/include/llvm/Analysis/ScalarEvolution.h
@@ -446,6 +446,21 @@ namespace llvm {
     /// extended, it is sign extended.
     SCEVHandle getTruncateOrSignExtend(const SCEVHandle &V, const Type *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 getNoopOrZeroExtend(const SCEVHandle &V, const Type *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 getNoopOrSignExtend(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.
+    SCEVHandle getTruncateOrNoop(const SCEVHandle &V, const Type *Ty);
+
     /// getIntegerSCEV - Given an integer or FP type, create a constant for the
     /// specified signed integer value and return a SCEV for the constant.
     SCEVHandle getIntegerSCEV(int Val, const Type *Ty);
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index a71db865cbf..77a80706314 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.