PR5207: Change APInt methods trunc(), sext(), zext(), sextOrTrunc() and
zextOrTrunc(), and APSInt methods extend(), extOrTrunc() and new method
trunc(), to be const and to return a new value instead of modifying the
object in place.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121120 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/ConstantRange.cpp b/lib/Support/ConstantRange.cpp
index 7f68fd3..493f708 100644
--- a/lib/Support/ConstantRange.cpp
+++ b/lib/Support/ConstantRange.cpp
@@ -442,9 +442,7 @@
     // Change into [0, 1 << src bit width)
     return ConstantRange(APInt(DstTySize,0), APInt(DstTySize,1).shl(SrcTySize));
 
-  APInt L = Lower; L.zext(DstTySize);
-  APInt U = Upper; U.zext(DstTySize);
-  return ConstantRange(L, U);
+  return ConstantRange(Lower.zext(DstTySize), Upper.zext(DstTySize));
 }
 
 /// signExtend - Return a new range in the specified integer type, which must
@@ -461,9 +459,7 @@
                          APInt::getLowBitsSet(DstTySize, SrcTySize-1) + 1);
   }
 
-  APInt L = Lower; L.sext(DstTySize);
-  APInt U = Upper; U.sext(DstTySize);
-  return ConstantRange(L, U);
+  return ConstantRange(Lower.sext(DstTySize), Upper.sext(DstTySize));
 }
 
 /// truncate - Return a new range in the specified integer type, which must be
@@ -477,9 +473,7 @@
   if (isFullSet() || getSetSize().ugt(Size))
     return ConstantRange(DstTySize, /*isFullSet=*/true);
 
-  APInt L = Lower; L.trunc(DstTySize);
-  APInt U = Upper; U.trunc(DstTySize);
-  return ConstantRange(L, U);
+  return ConstantRange(Lower.trunc(DstTySize), Upper.trunc(DstTySize));
 }
 
 /// zextOrTrunc - make this range have the bit width given by \p DstTySize. The