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-rw-r--r--include/llvm/Support/MathExtras.h120
-rw-r--r--unittests/Support/MathExtrasTest.cpp28
2 files changed, 15 insertions, 133 deletions
diff --git a/include/llvm/Support/MathExtras.h b/include/llvm/Support/MathExtras.h
index 272354f..be76f32 100644
--- a/include/llvm/Support/MathExtras.h
+++ b/include/llvm/Support/MathExtras.h
@@ -374,84 +374,12 @@ inline uint64_t ByteSwap_64(uint64_t Value) {
return sys::SwapByteOrder_64(Value);
}
-/// CountLeadingZeros_32 - this function performs the platform optimal form of
-/// counting the number of zeros from the most significant bit to the first one
-/// bit. Ex. CountLeadingZeros_32(0x00F000FF) == 8.
-/// Returns 32 if the word is zero.
-inline unsigned CountLeadingZeros_32(uint32_t Value) {
- unsigned Count; // result
-#if __GNUC__ >= 4
- // PowerPC is defined for __builtin_clz(0)
-#if !defined(__ppc__) && !defined(__ppc64__)
- if (!Value) return 32;
-#endif
- Count = __builtin_clz(Value);
-#else
- if (!Value) return 32;
- Count = 0;
- // bisection method for count leading zeros
- for (unsigned Shift = 32 >> 1; Shift; Shift >>= 1) {
- uint32_t Tmp = Value >> Shift;
- if (Tmp) {
- Value = Tmp;
- } else {
- Count |= Shift;
- }
- }
-#endif
- return Count;
-}
-
/// CountLeadingOnes_32 - this function performs the operation of
/// counting the number of ones from the most significant bit to the first zero
/// bit. Ex. CountLeadingOnes_32(0xFF0FFF00) == 8.
/// Returns 32 if the word is all ones.
inline unsigned CountLeadingOnes_32(uint32_t Value) {
- return CountLeadingZeros_32(~Value);
-}
-
-/// CountLeadingZeros_64 - This function performs the platform optimal form
-/// of counting the number of zeros from the most significant bit to the first
-/// one bit (64 bit edition.)
-/// Returns 64 if the word is zero.
-inline unsigned CountLeadingZeros_64(uint64_t Value) {
- unsigned Count; // result
-#if __GNUC__ >= 4
- // PowerPC is defined for __builtin_clzll(0)
-#if !defined(__ppc__) && !defined(__ppc64__)
- if (!Value) return 64;
-#endif
- Count = __builtin_clzll(Value);
-#else
- if (sizeof(long) == sizeof(int64_t)) {
- if (!Value) return 64;
- Count = 0;
- // bisection method for count leading zeros
- for (unsigned Shift = 64 >> 1; Shift; Shift >>= 1) {
- uint64_t Tmp = Value >> Shift;
- if (Tmp) {
- Value = Tmp;
- } else {
- Count |= Shift;
- }
- }
- } else {
- // get hi portion
- uint32_t Hi = Hi_32(Value);
-
- // if some bits in hi portion
- if (Hi) {
- // leading zeros in hi portion plus all bits in lo portion
- Count = CountLeadingZeros_32(Hi);
- } else {
- // get lo portion
- uint32_t Lo = Lo_32(Value);
- // same as 32 bit value
- Count = CountLeadingZeros_32(Lo)+32;
- }
- }
-#endif
- return Count;
+ return countLeadingZeros(~Value);
}
/// CountLeadingOnes_64 - This function performs the operation
@@ -459,27 +387,7 @@ inline unsigned CountLeadingZeros_64(uint64_t Value) {
/// zero bit (64 bit edition.)
/// Returns 64 if the word is all ones.
inline unsigned CountLeadingOnes_64(uint64_t Value) {
- return CountLeadingZeros_64(~Value);
-}
-
-/// CountTrailingZeros_32 - this function performs the platform optimal form of
-/// counting the number of zeros from the least significant bit to the first one
-/// bit. Ex. CountTrailingZeros_32(0xFF00FF00) == 8.
-/// Returns 32 if the word is zero.
-inline unsigned CountTrailingZeros_32(uint32_t Value) {
-#if __GNUC__ >= 4
- return Value ? __builtin_ctz(Value) : 32;
-#else
- static const unsigned Mod37BitPosition[] = {
- 32, 0, 1, 26, 2, 23, 27, 0, 3, 16, 24, 30, 28, 11, 0, 13,
- 4, 7, 17, 0, 25, 22, 31, 15, 29, 10, 12, 6, 0, 21, 14, 9,
- 5, 20, 8, 19, 18
- };
- // Replace "-Value" by "1+~Value" in the following commented code to avoid
- // MSVC warning C4146
- // return Mod37BitPosition[(-Value & Value) % 37];
- return Mod37BitPosition[((1 + ~Value) & Value) % 37];
-#endif
+ return countLeadingZeros(~Value);
}
/// CountTrailingOnes_32 - this function performs the operation of
@@ -487,29 +395,7 @@ inline unsigned CountTrailingZeros_32(uint32_t Value) {
/// bit. Ex. CountTrailingOnes_32(0x00FF00FF) == 8.
/// Returns 32 if the word is all ones.
inline unsigned CountTrailingOnes_32(uint32_t Value) {
- return CountTrailingZeros_32(~Value);
-}
-
-/// CountTrailingZeros_64 - This function performs the platform optimal form
-/// of counting the number of zeros from the least significant bit to the first
-/// one bit (64 bit edition.)
-/// Returns 64 if the word is zero.
-inline unsigned CountTrailingZeros_64(uint64_t Value) {
-#if __GNUC__ >= 4
- return Value ? __builtin_ctzll(Value) : 64;
-#else
- static const unsigned Mod67Position[] = {
- 64, 0, 1, 39, 2, 15, 40, 23, 3, 12, 16, 59, 41, 19, 24, 54,
- 4, 64, 13, 10, 17, 62, 60, 28, 42, 30, 20, 51, 25, 44, 55,
- 47, 5, 32, 65, 38, 14, 22, 11, 58, 18, 53, 63, 9, 61, 27,
- 29, 50, 43, 46, 31, 37, 21, 57, 52, 8, 26, 49, 45, 36, 56,
- 7, 48, 35, 6, 34, 33, 0
- };
- // Replace "-Value" by "1+~Value" in the following commented code to avoid
- // MSVC warning C4146
- // return Mod67Position[(-Value & Value) % 67];
- return Mod67Position[((1 + ~Value) & Value) % 67];
-#endif
+ return countTrailingZeros(~Value);
}
/// CountTrailingOnes_64 - This function performs the operation
diff --git a/unittests/Support/MathExtrasTest.cpp b/unittests/Support/MathExtrasTest.cpp
index f3f32b7..93a38cb 100644
--- a/unittests/Support/MathExtrasTest.cpp
+++ b/unittests/Support/MathExtrasTest.cpp
@@ -52,6 +52,18 @@ TEST(MathExtras, countLeadingZeros) {
EXPECT_EQ(10u, countLeadingZeros(NZ16));
EXPECT_EQ(26u, countLeadingZeros(NZ32));
EXPECT_EQ(58u, countLeadingZeros(NZ64));
+
+ EXPECT_EQ(8u, countLeadingZeros(0x00F000FFu));
+ EXPECT_EQ(8u, countLeadingZeros(0x00F12345u));
+ for (unsigned i = 0; i <= 30; ++i) {
+ EXPECT_EQ(31 - i, countLeadingZeros(1u << i));
+ }
+
+ EXPECT_EQ(8u, countLeadingZeros(0x00F1234500F12345ULL));
+ EXPECT_EQ(1u, countLeadingZeros(1ULL << 62));
+ for (unsigned i = 0; i <= 62; ++i) {
+ EXPECT_EQ(63 - i, countLeadingZeros(1ULL << i));
+ }
}
TEST(MathExtras, findFirstSet) {
@@ -129,22 +141,6 @@ TEST(MathExtras, ByteSwap_64) {
EXPECT_EQ(0x1100FFEEDDCCBBAAULL, ByteSwap_64(0xAABBCCDDEEFF0011LL));
}
-TEST(MathExtras, CountLeadingZeros_32) {
- EXPECT_EQ(8u, CountLeadingZeros_32(0x00F000FF));
- EXPECT_EQ(8u, CountLeadingZeros_32(0x00F12345));
- for (unsigned i = 0; i <= 30; ++i) {
- EXPECT_EQ(31 - i, CountLeadingZeros_32(1 << i));
- }
-}
-
-TEST(MathExtras, CountLeadingZeros_64) {
- EXPECT_EQ(8u, CountLeadingZeros_64(0x00F1234500F12345LL));
- EXPECT_EQ(1u, CountLeadingZeros_64(1LL << 62));
- for (unsigned i = 0; i <= 62; ++i) {
- EXPECT_EQ(63 - i, CountLeadingZeros_64(1LL << i));
- }
-}
-
TEST(MathExtras, CountLeadingOnes_32) {
for (int i = 30; i >= 0; --i) {
// Start with all ones and unset some bit.
generated by cgit v1.1 at 2025-01-08 16:29:33 +0000