Actually, for getHighBitsSet and getLowBitsSet, don't make a 0 bit size

illegal. Instead do the 0 valued construction for the user. This is because
the caller may not know (or care to check) that the number of bits set is
zero.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35315 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/ADT/APInt.h b/include/llvm/ADT/APInt.h
index 8f3b2f6a6d4421683a3925b2b4d8cbc78e82df83..7e5132f0d023d4247404d304141978b1a0af6b71 100644 (file)
--- a/include/llvm/ADT/APInt.h
+++ b/include/llvm/ADT/APInt.h
@@ -355,7 +355,9 @@ public:
   /// @brief Get a value with high bits set
   static APInt getHighBitsSet(uint32_t numBits, uint32_t hiBitsSet) {
     assert(hiBitsSet <= numBits && "Too many bits to set!");
-    assert(hiBitsSet > 0 && "You must set SOME bits");
+    // Handle a degenerate case, to avoid shifting by word size
+    if (hiBitsSet == 0)
+      return APInt(numBits, 0);
     uint32_t shiftAmt = numBits - hiBitsSet;
     // For small values, return quickly
     if (numBits <= APINT_BITS_PER_WORD)
@@ -369,7 +371,9 @@ public:
   /// @brief Get a value with low bits set
   static APInt getLowBitsSet(uint32_t numBits, uint32_t loBitsSet) {
     assert(loBitsSet <= numBits && "Too many bits to set!");
-    assert(loBitsSet > 0 && "You must set SOME bits");
+    // Handle a degenerate case, to avoid shifting by word size
+    if (loBitsSet == 0)
+      return APInt(numBits, 0);
     uint32_t shiftAmt = numBits - loBitsSet;
     // For small values, return quickly
     if (numBits <= APINT_BITS_PER_WORD)