From 35b1423ee67a6ec7052016dda486e6ee4a118db4 Mon Sep 17 00:00:00 2001 From: Meador Inge Date: Thu, 7 Feb 2013 18:36:50 +0000 Subject: [PATCH] ADT: Correct APInt::getActiveWords for zero values PR15138 was opened because of a segfault in the Bitcode writer. The actual issue ended up being a bug in APInt where calls to APInt::getActiveWords returns a bogus value when the APInt value is 0. This patch fixes the problem by ensuring that getActiveWords returns 1 for 0 valued APInts. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174641 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/ADT/APInt.h | 3 ++- unittests/ADT/APIntTest.cpp | 8 ++++++++ 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/include/llvm/ADT/APInt.h b/include/llvm/ADT/APInt.h index e67e032ace0..2e623a1e0dd 100644 --- a/include/llvm/ADT/APInt.h +++ b/include/llvm/ADT/APInt.h @@ -1191,7 +1191,8 @@ public: /// APInt. This is used in conjunction with getActiveData to extract the raw /// value of the APInt. unsigned getActiveWords() const { - return whichWord(getActiveBits()-1) + 1; + unsigned numActiveBits = getActiveBits(); + return numActiveBits ? whichWord(numActiveBits - 1) + 1 : 1; } /// Computes the minimum bit width for this APInt while considering it to be diff --git a/unittests/ADT/APIntTest.cpp b/unittests/ADT/APIntTest.cpp index 2a4c5b4c494..2510bc738d4 100644 --- a/unittests/ADT/APIntTest.cpp +++ b/unittests/ADT/APIntTest.cpp @@ -56,6 +56,14 @@ TEST(APIntTest, i33_Count) { #endif TEST(APIntTest, i65_Count) { + APInt i65(65, 0, true); + EXPECT_EQ(65u, i65.countLeadingZeros()); + EXPECT_EQ(0u, i65.countLeadingOnes()); + EXPECT_EQ(0u, i65.getActiveBits()); + EXPECT_EQ(1u, i65.getActiveWords()); + EXPECT_EQ(65u, i65.countTrailingZeros()); + EXPECT_EQ(0u, i65.countPopulation()); + APInt i65minus(65, 0, true); i65minus.setBit(64); EXPECT_EQ(0u, i65minus.countLeadingZeros()); -- 2.34.1