From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Sun, 21 Jul 2019 16:06:26 +0000 (+0000)
Subject: [SmallBitVector] Fix bug in find_next_unset for small types with indices >=32
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=9b4b52095ce2e446960d1085aee9085aa331ec71;p=llvm

[SmallBitVector] Fix bug in find_next_unset for small types with indices >=32

We were creating a bitmask from a shift of unsigned instead of uintptr_t, meaning we couldn't create masks for indices above 31.

Noticed due to a MSVC analyzer warning.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366657 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/ADT/SmallBitVector.h b/include/llvm/ADT/SmallBitVector.h
index 742450e6a95..61375c00802 100644
--- a/include/llvm/ADT/SmallBitVector.h
+++ b/include/llvm/ADT/SmallBitVector.h
@@ -290,7 +290,7 @@ public:
       ++Prev;
       uintptr_t Bits = getSmallBits();
       // Mask in previous bits.
-      uintptr_t Mask = (1 << Prev) - 1;
+      uintptr_t Mask = (uintptr_t(1) << Prev) - 1;
       Bits |= Mask;
 
       if (Bits == ~uintptr_t(0) || Prev + 1 >= getSmallSize())
diff --git a/unittests/ADT/BitVectorTest.cpp b/unittests/ADT/BitVectorTest.cpp
index 559dcc579d1..fea58422c5f 100644
--- a/unittests/ADT/BitVectorTest.cpp
+++ b/unittests/ADT/BitVectorTest.cpp
@@ -228,6 +228,38 @@ TYPED_TEST(BitVectorTest, SimpleFindOpsMultiWord) {
   EXPECT_EQ(99, A.find_next_unset(98));
 }
 
+// Test finding next set and unset bits in a BitVector/SmallBitVector within a
+// uintptr_t - check both 32-bit (Multi) and 64-bit (Small) targets.
+TYPED_TEST(BitVectorTest, SimpleFindOps64Bit) {
+  TypeParam A;
+
+  A.resize(57);
+  A.set(12);
+  A.set(13);
+  A.set(47);
+
+  EXPECT_EQ(47, A.find_last());
+  EXPECT_EQ(12, A.find_first());
+  EXPECT_EQ(13, A.find_next(12));
+  EXPECT_EQ(47, A.find_next(13));
+  EXPECT_EQ(-1, A.find_next(47));
+
+  EXPECT_EQ(-1, A.find_prev(12));
+  EXPECT_EQ(12, A.find_prev(13));
+  EXPECT_EQ(13, A.find_prev(47));
+  EXPECT_EQ(47, A.find_prev(56));
+
+  EXPECT_EQ(0, A.find_first_unset());
+  EXPECT_EQ(56, A.find_last_unset());
+  EXPECT_EQ(14, A.find_next_unset(11));
+  EXPECT_EQ(14, A.find_next_unset(12));
+  EXPECT_EQ(14, A.find_next_unset(13));
+  EXPECT_EQ(16, A.find_next_unset(15));
+  EXPECT_EQ(48, A.find_next_unset(46));
+  EXPECT_EQ(48, A.find_next_unset(47));
+  EXPECT_EQ(-1, A.find_next_unset(56));
+}
+
 // Check if a SmallBitVector is in small mode. This check is used in tests
 // that run for both SmallBitVector and BitVector. This check doesn't apply
 // to BitVector so we provide an overload that returns true to get the tests