From 2d0f1c57c3f95e43a8b18bfe8481d90b665d5efe Mon Sep 17 00:00:00 2001
From: Torok Edwin <edwintorok@gmail.com>
Date: Tue, 27 Jan 2009 18:06:03 +0000
Subject: [PATCH] APInt's countLeadingOnes() was broken for negative i128
 values, causing assertion failures in getSExtValue(). Fix it by making
 highWordBits actually contain what its name says, and add some more
 unit-tests for APInt. This fixes PR3419.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63107 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Support/APInt.cpp   |  8 ++++-
 unittests/ADT/APInt.cpp | 79 +++++++++++++++++++++++++++++++++++++++--
 2 files changed, 84 insertions(+), 3 deletions(-)

diff --git a/lib/Support/APInt.cpp b/lib/Support/APInt.cpp
index 367c75be1af..3d38a0c6066 100644
--- a/lib/Support/APInt.cpp
+++ b/lib/Support/APInt.cpp
@@ -683,7 +683,13 @@ unsigned APInt::countLeadingOnes() const {
     return countLeadingOnes_64(VAL, APINT_BITS_PER_WORD - BitWidth);
 
   unsigned highWordBits = BitWidth % APINT_BITS_PER_WORD;
-  unsigned shift = (highWordBits == 0 ? 0 : APINT_BITS_PER_WORD - highWordBits);
+  unsigned shift;
+  if (!highWordBits) {
+    highWordBits = APINT_BITS_PER_WORD;
+    shift = 0;
+  } else {
+    shift = APINT_BITS_PER_WORD - highWordBits;
+  }
   int i = getNumWords() - 1;
   unsigned Count = countLeadingOnes_64(pVal[i], shift);
   if (Count == highWordBits) {
diff --git a/unittests/ADT/APInt.cpp b/unittests/ADT/APInt.cpp
index 5bca5b6b406..cbcc1390bca 100644
--- a/unittests/ADT/APInt.cpp
+++ b/unittests/ADT/APInt.cpp
@@ -18,8 +18,83 @@ namespace {
 TEST(APIntTest, ShiftLeftByZero) {
   APInt One = APInt::getNullValue(65) + 1;
   APInt Shl = One.shl(0);
-  EXPECT_EQ(Shl[0], true);
-  EXPECT_EQ(Shl[1], false);
+  EXPECT_EQ(true, Shl[0]);
+  EXPECT_EQ(false, Shl[1]);
+}
+
+TEST(APIntTest, I128NegativeCount) {
+  APInt Minus3(128, (uint64_t)-3, true);
+  EXPECT_EQ(126u, Minus3.countLeadingOnes());
+  EXPECT_EQ(-3, Minus3.getSExtValue());
+
+  APInt Minus1(128, (uint64_t)-1, true);
+  EXPECT_EQ(0u, Minus1.countLeadingZeros());
+  EXPECT_EQ(128u, Minus1.countLeadingOnes());
+  EXPECT_EQ(128u, Minus1.getActiveBits());
+  EXPECT_EQ(0u, Minus1.countTrailingZeros());
+  EXPECT_EQ(128u, Minus1.countTrailingOnes());
+  EXPECT_EQ(128u, Minus1.countPopulation());
+  EXPECT_EQ(-1, Minus1.getSExtValue());
+}
+
+TEST(APIntTest, I33Count) {
+  APInt i33minus2(33, -2, true);
+  EXPECT_EQ(0u, i33minus2.countLeadingZeros());
+  EXPECT_EQ(32u, i33minus2.countLeadingOnes());
+  EXPECT_EQ(33u, i33minus2.getActiveBits());
+  EXPECT_EQ(1u, i33minus2.countTrailingZeros());
+  EXPECT_EQ(32u, i33minus2.countPopulation());
+  EXPECT_EQ(-2, i33minus2.getSExtValue());
+  EXPECT_EQ(((uint64_t)-2)&((1ull<<33) -1), i33minus2.getZExtValue());
+}
+
+TEST(APIntTest, I65Count) {
+  APInt i65minus(65, 0, true);
+  i65minus.set(64);
+  EXPECT_EQ(0u, i65minus.countLeadingZeros());
+  EXPECT_EQ(1u, i65minus.countLeadingOnes());
+  EXPECT_EQ(65u, i65minus.getActiveBits());
+  EXPECT_EQ(64u, i65minus.countTrailingZeros());
+  EXPECT_EQ(1u, i65minus.countPopulation());
+}
+
+TEST(APIntTest, I128PositiveCount) {
+  APInt u128max = APInt::getAllOnesValue(128);
+  EXPECT_EQ(128u, u128max.countLeadingOnes());
+  EXPECT_EQ(0u, u128max.countLeadingZeros());
+  EXPECT_EQ(128u, u128max.getActiveBits());
+  EXPECT_EQ(0u, u128max.countTrailingZeros());
+  EXPECT_EQ(128u, u128max.countTrailingOnes());
+  EXPECT_EQ(128u, u128max.countPopulation());
+
+  APInt u64max(128, (uint64_t)-1, false);
+  EXPECT_EQ(64u, u64max.countLeadingZeros());
+  EXPECT_EQ(0u, u64max.countLeadingOnes());
+  EXPECT_EQ(64u, u64max.getActiveBits());
+  EXPECT_EQ(0u, u64max.countTrailingZeros());
+  EXPECT_EQ(64u, u64max.countTrailingOnes());
+  EXPECT_EQ(64u, u64max.countPopulation());
+  EXPECT_EQ((uint64_t)~0ull, u64max.getZExtValue());
+
+  APInt zero(128, 0, true);
+  EXPECT_EQ(128u, zero.countLeadingZeros());
+  EXPECT_EQ(0u, zero.countLeadingOnes());
+  EXPECT_EQ(0u, zero.getActiveBits());
+  EXPECT_EQ(128u, zero.countTrailingZeros());
+  EXPECT_EQ(0u, zero.countTrailingOnes());
+  EXPECT_EQ(0u, zero.countPopulation());
+  EXPECT_EQ(0u, zero.getSExtValue());
+  EXPECT_EQ(0u, zero.getZExtValue());
+
+  APInt one(128, 1, true);
+  EXPECT_EQ(127u, one.countLeadingZeros());
+  EXPECT_EQ(0u, one.countLeadingOnes());
+  EXPECT_EQ(1u, one.getActiveBits());
+  EXPECT_EQ(0u, one.countTrailingZeros());
+  EXPECT_EQ(1u, one.countTrailingOnes());
+  EXPECT_EQ(1u, one.countPopulation());
+  EXPECT_EQ(1, one.getSExtValue());
+  EXPECT_EQ(1u, one.getZExtValue());
 }
 
 }
-- 
2.34.1