X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FSupport%2FConstantRange.cpp;h=265b6e96a74698486da4881795f8d986bc985faf;hb=b9536ac581d0d74b29c11dcb33e22200b22b86b1;hp=b83dcccca67a3adb21c06d8cdb58c7d2937e48cc;hpb=367308f798338e162b4ab76efa785caa847487c0;p=oota-llvm.git

diff --git a/lib/Support/ConstantRange.cpp b/lib/Support/ConstantRange.cpp
index b83dcccca67..265b6e96a74 100644
--- a/lib/Support/ConstantRange.cpp
+++ b/lib/Support/ConstantRange.cpp
@@ -21,7 +21,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/InstrTypes.h"
+#include "llvm/IR/InstrTypes.h"
 #include "llvm/Support/ConstantRange.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
@@ -38,13 +38,14 @@ ConstantRange::ConstantRange(uint32_t BitWidth, bool Full) {
 
 /// Initialize a range to hold the single specified value.
 ///
-ConstantRange::ConstantRange(const APInt &V) : Lower(V), Upper(V + 1) {}
+ConstantRange::ConstantRange(APIntMoveTy V)
+    : Lower(llvm_move(V)), Upper(Lower + 1) {}
 
-ConstantRange::ConstantRange(const APInt &L, const APInt &U) :
-  Lower(L), Upper(U) {
-  assert(L.getBitWidth() == U.getBitWidth() &&
+ConstantRange::ConstantRange(APIntMoveTy L, APIntMoveTy U)
+    : Lower(llvm_move(L)), Upper(llvm_move(U)) {
+  assert(Lower.getBitWidth() == Upper.getBitWidth() &&
          "ConstantRange with unequal bit widths");
-  assert((L != U || (L.isMaxValue() || L.isMinValue())) &&
+  assert((Lower != Upper || (Lower.isMaxValue() || Lower.isMinValue())) &&
          "Lower == Upper, but they aren't min or max value!");
 }
 
@@ -143,17 +144,13 @@ bool ConstantRange::isSignWrappedSet() const {
 /// getSetSize - Return the number of elements in this set.
 ///
 APInt ConstantRange::getSetSize() const {
-  if (isEmptySet())
-    return APInt(getBitWidth()+1, 0);
-
-  if (isFullSet())
-    return APInt::getMaxValue(getBitWidth()).zext(getBitWidth()+1) + 1;
-
-  if (isWrappedSet()) {
-    APInt Result = Upper + (APInt::getMaxValue(getBitWidth()) - Lower + 1);
-    return Result.zext(getBitWidth()+1);
+  if (isFullSet()) {
+    APInt Size(getBitWidth()+1, 0);
+    Size.setBit(getBitWidth());
+    return Size;
   }
 
+  // This is also correct for wrapped sets.
   return (Upper - Lower).zext(getBitWidth()+1);
 }
 
@@ -428,9 +425,13 @@ ConstantRange ConstantRange::zeroExtend(uint32_t DstTySize) const {
 
   unsigned SrcTySize = getBitWidth();
   assert(SrcTySize < DstTySize && "Not a value extension");
-  if (isFullSet() || isWrappedSet())
+  if (isFullSet() || isWrappedSet()) {
     // Change into [0, 1 << src bit width)
-    return ConstantRange(APInt(DstTySize,0), APInt(DstTySize,1).shl(SrcTySize));
+    APInt LowerExt(DstTySize, 0);
+    if (!Upper) // special case: [X, 0) -- not really wrapping around
+      LowerExt = Lower.zext(DstTySize);
+    return ConstantRange(LowerExt, APInt::getOneBitSet(DstTySize, SrcTySize));
+  }
 
   return ConstantRange(Lower.zext(DstTySize), Upper.zext(DstTySize));
 }
@@ -444,6 +445,11 @@ ConstantRange ConstantRange::signExtend(uint32_t DstTySize) const {
 
   unsigned SrcTySize = getBitWidth();
   assert(SrcTySize < DstTySize && "Not a value extension");
+
+  // special case: [X, INT_MIN) -- not really wrapping around
+  if (Upper.isMinSignedValue())
+    return ConstantRange(Lower.sext(DstTySize), Upper.zext(DstTySize));
+
   if (isFullSet() || isSignWrappedSet()) {
     return ConstantRange(APInt::getHighBitsSet(DstTySize,DstTySize-SrcTySize+1),
                          APInt::getLowBitsSet(DstTySize, SrcTySize-1) + 1);
@@ -458,10 +464,53 @@ ConstantRange ConstantRange::signExtend(uint32_t DstTySize) const {
 /// truncated to the specified type.
 ConstantRange ConstantRange::truncate(uint32_t DstTySize) const {
   assert(getBitWidth() > DstTySize && "Not a value truncation");
-  if (isFullSet() || getSetSize().getActiveBits() > DstTySize)
+  if (isEmptySet())
+    return ConstantRange(DstTySize, /*isFullSet=*/false);
+  if (isFullSet())
     return ConstantRange(DstTySize, /*isFullSet=*/true);
 
-  return ConstantRange(Lower.trunc(DstTySize), Upper.trunc(DstTySize));
+  APInt MaxValue = APInt::getMaxValue(DstTySize).zext(getBitWidth());
+  APInt MaxBitValue(getBitWidth(), 0);
+  MaxBitValue.setBit(DstTySize);
+
+  APInt LowerDiv(Lower), UpperDiv(Upper);
+  ConstantRange Union(DstTySize, /*isFullSet=*/false);
+
+  // Analyze wrapped sets in their two parts: [0, Upper) \/ [Lower, MaxValue]
+  // We use the non-wrapped set code to analyze the [Lower, MaxValue) part, and
+  // then we do the union with [MaxValue, Upper)
+  if (isWrappedSet()) {
+    // if Upper is greater than Max Value, it covers the whole truncated range.
+    if (Upper.uge(MaxValue))
+      return ConstantRange(DstTySize, /*isFullSet=*/true);
+
+    Union = ConstantRange(APInt::getMaxValue(DstTySize),Upper.trunc(DstTySize));
+    UpperDiv = APInt::getMaxValue(getBitWidth());
+
+    // Union covers the MaxValue case, so return if the remaining range is just
+    // MaxValue.
+    if (LowerDiv == UpperDiv)
+      return Union;
+  }
+
+  // Chop off the most significant bits that are past the destination bitwidth.
+  if (LowerDiv.uge(MaxValue)) {
+    APInt Div(getBitWidth(), 0);
+    APInt::udivrem(LowerDiv, MaxBitValue, Div, LowerDiv);
+    UpperDiv = UpperDiv - MaxBitValue * Div;
+  }
+
+  if (UpperDiv.ule(MaxValue))
+    return ConstantRange(LowerDiv.trunc(DstTySize),
+                         UpperDiv.trunc(DstTySize)).unionWith(Union);
+
+  // The truncated value wrapps around. Check if we can do better than fullset.
+  APInt UpperModulo = UpperDiv - MaxBitValue;
+  if (UpperModulo.ult(LowerDiv))
+    return ConstantRange(LowerDiv.trunc(DstTySize),
+                         UpperModulo.trunc(DstTySize)).unionWith(Union);
+
+  return ConstantRange(DstTySize, /*isFullSet=*/true);
 }
 
 /// zextOrTrunc - make this range have the bit width given by \p DstTySize. The
@@ -537,8 +586,6 @@ ConstantRange::multiply(const ConstantRange &Other) const {
 
   if (isEmptySet() || Other.isEmptySet())
     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
-  if (isFullSet() || Other.isFullSet())
-    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 
   APInt this_min = getUnsignedMin().zext(getBitWidth() * 2);
   APInt this_max = getUnsignedMax().zext(getBitWidth() * 2);