[llvm] r347148 - tighten up a couple of assertions. hitting the BitPosition == BitWidth case that was previously not caught resulted in nasty corruption of APInts that (on my system at least) could not be detected using UBSan, ASan, or Valgrind. this patch does not cause any extra failures in a check-all nor does it interfere with bootstrapping. David Blaikie informally approved this change.

[John Regehr via llvm-commits]

Author: regehr
Date: Sat Nov 17 17:51:43 2018
New Revision: 347148

URL: http://llvm.org/viewvc/llvm-project?rev=347148&view=rev
Log:
tighten up a couple of assertions. hitting the BitPosition == BitWidth case that was previously not caught resulted in nasty corruption of APInts that (on my system at least) could not be detected using UBSan, ASan, or Valgrind. this patch does not cause any extra failures in a check-all nor does it interfere with bootstrapping. David Blaikie informally approved this change.

Modified:
    llvm/trunk/include/llvm/ADT/APInt.h

Modified: llvm/trunk/include/llvm/ADT/APInt.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/APInt.h?rev=347148&r1=347147&r2=347148&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/APInt.h (original)
+++ llvm/trunk/include/llvm/ADT/APInt.h Sat Nov 17 17:51:43 2018
@@ -1395,7 +1395,7 @@ public:
   ///
   /// Set the given bit to 1 whose position is given as "bitPosition".
   void setBit(unsigned BitPosition) {
-    assert(BitPosition <= BitWidth && "BitPosition out of range");
+    assert(BitPosition < BitWidth && "BitPosition out of range");
     WordType Mask = maskBit(BitPosition);
     if (isSingleWord())
       U.VAL |= Mask;
@@ -1454,7 +1454,7 @@ public:
   ///
   /// Set the given bit to 0 whose position is given as "bitPosition".
   void clearBit(unsigned BitPosition) {
-    assert(BitPosition <= BitWidth && "BitPosition out of range");
+    assert(BitPosition < BitWidth && "BitPosition out of range");
     WordType Mask = ~maskBit(BitPosition);
     if (isSingleWord())
       U.VAL &= Mask;