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[Support] make countLeadingZeros() and countTrailingZeros() return unsigned 

This matches countLeadingOnes() and countTrailingOnes(), and
APInt's countLeadingZeros() and countTrailingZeros().

(as well as __builtin_clzll())

llvm-svn: 361724
This commit is contained in:
Shawn Landden 2019-05-26 13:49:58 +00:00
parent d0f13e618f
commit b7cc093db2
3 changed files with 25 additions and 24 deletions
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24
llvm/include/llvm/Support/MathExtras.h
View File

@ -51,14 +51,14 @@ enum ZeroBehavior {
namespace detail {
template <typename T, std::size_t SizeOfT> struct TrailingZerosCounter {
static std::size_t count(T Val, ZeroBehavior) {
static unsigned count(T Val, ZeroBehavior) {
if (!Val)
return std::numeric_limits<T>::digits;
if (Val & 0x1)
return 0;
// Bisection method.
std::size_t ZeroBits = 0;
unsigned ZeroBits = 0;
T Shift = std::numeric_limits<T>::digits >> 1;
T Mask = std::numeric_limits<T>::max() >> Shift;
while (Shift) {
@ -75,7 +75,7 @@ template <typename T, std::size_t SizeOfT> struct TrailingZerosCounter {
#if __GNUC__ >= 4 || defined(_MSC_VER)
template <typename T> struct TrailingZerosCounter<T, 4> {
static std::size_t count(T Val, ZeroBehavior ZB) {
static unsigned count(T Val, ZeroBehavior ZB) {
if (ZB != ZB_Undefined && Val == 0)
return 32;
@ -91,7 +91,7 @@ template <typename T> struct TrailingZerosCounter<T, 4> {
#if !defined(_MSC_VER) || defined(_M_X64)
template <typename T> struct TrailingZerosCounter<T, 8> {
static std::size_t count(T Val, ZeroBehavior ZB) {
static unsigned count(T Val, ZeroBehavior ZB) {
if (ZB != ZB_Undefined && Val == 0)
return 64;
@ -116,7 +116,7 @@ template <typename T> struct TrailingZerosCounter<T, 8> {
/// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are
/// valid arguments.
template <typename T>
std::size_t countTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) {
unsigned countTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) {
static_assert(std::numeric_limits<T>::is_integer &&
!std::numeric_limits<T>::is_signed,
"Only unsigned integral types are allowed.");
@ -125,12 +125,12 @@ std::size_t countTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) {
namespace detail {
template <typename T, std::size_t SizeOfT> struct LeadingZerosCounter {
static std::size_t count(T Val, ZeroBehavior) {
static unsigned count(T Val, ZeroBehavior) {
if (!Val)
return std::numeric_limits<T>::digits;
// Bisection method.
std::size_t ZeroBits = 0;
unsigned ZeroBits = 0;
for (T Shift = std::numeric_limits<T>::digits >> 1; Shift; Shift >>= 1) {
T Tmp = Val >> Shift;
if (Tmp)
@ -144,7 +144,7 @@ template <typename T, std::size_t SizeOfT> struct LeadingZerosCounter {
#if __GNUC__ >= 4 || defined(_MSC_VER)
template <typename T> struct LeadingZerosCounter<T, 4> {
static std::size_t count(T Val, ZeroBehavior ZB) {
static unsigned count(T Val, ZeroBehavior ZB) {
if (ZB != ZB_Undefined && Val == 0)
return 32;
@ -160,7 +160,7 @@ template <typename T> struct LeadingZerosCounter<T, 4> {
#if !defined(_MSC_VER) || defined(_M_X64)
template <typename T> struct LeadingZerosCounter<T, 8> {
static std::size_t count(T Val, ZeroBehavior ZB) {
static unsigned count(T Val, ZeroBehavior ZB) {
if (ZB != ZB_Undefined && Val == 0)
return 64;
@ -185,7 +185,7 @@ template <typename T> struct LeadingZerosCounter<T, 8> {
/// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are
/// valid arguments.
template <typename T>
std::size_t countLeadingZeros(T Val, ZeroBehavior ZB = ZB_Width) {
unsigned countLeadingZeros(T Val, ZeroBehavior ZB = ZB_Width) {
static_assert(std::numeric_limits<T>::is_integer &&
!std::numeric_limits<T>::is_signed,
"Only unsigned integral types are allowed.");
@ -458,7 +458,7 @@ inline uint64_t ByteSwap_64(uint64_t Value) {
/// \param ZB the behavior on an input of all ones. Only ZB_Width and
/// ZB_Undefined are valid arguments.
template <typename T>
std::size_t countLeadingOnes(T Value, ZeroBehavior ZB = ZB_Width) {
unsigned countLeadingOnes(T Value, ZeroBehavior ZB = ZB_Width) {
static_assert(std::numeric_limits<T>::is_integer &&
!std::numeric_limits<T>::is_signed,
"Only unsigned integral types are allowed.");
@ -474,7 +474,7 @@ std::size_t countLeadingOnes(T Value, ZeroBehavior ZB = ZB_Width) {
/// \param ZB the behavior on an input of all ones. Only ZB_Width and
/// ZB_Undefined are valid arguments.
template <typename T>
std::size_t countTrailingOnes(T Value, ZeroBehavior ZB = ZB_Width) {
unsigned countTrailingOnes(T Value, ZeroBehavior ZB = ZB_Width) {
static_assert(std::numeric_limits<T>::is_integer &&
!std::numeric_limits<T>::is_signed,
"Only unsigned integral types are allowed.");

2
llvm/lib/Target/AMDGPU/AMDGPUAsmPrinter.cpp
View File

@ -1147,7 +1147,7 @@ void AMDGPUAsmPrinter::getAmdKernelCode(amd_kernel_code_t &Out,
// These alignment values are specified in powers of two, so alignment =
// 2^n. The minimum alignment is 2^4 = 16.
Out.kernarg_segment_alignment = std::max((size_t)4,
Out.kernarg_segment_alignment = std::max<size_t>(4,
countTrailingZeros(MaxKernArgAlign));
}

23
llvm/lib/Transforms/Utils/SimplifyCFG.cpp
View File

@ -5377,8 +5377,8 @@ static bool SwitchToLookupTable(SwitchInst *SI, IRBuilder<> &Builder,
if (MinCaseVal->isNullValue())
TableIndex = SI->getCondition();
else
TableIndex = Builder.CreateSub(SI->getCondition(), MinCaseVal,
"switch.tableidx");
TableIndex =
Builder.CreateSub(SI->getCondition(), MinCaseVal, "switch.tableidx");
// Compute the maximum table size representable by the integer type we are
// switching upon.
@ -5512,7 +5512,8 @@ static bool isSwitchDense(ArrayRef<int64_t> Values) {
uint64_t Diff = (uint64_t)Values.back() - (uint64_t)Values.front();
uint64_t Range = Diff + 1;
uint64_t NumCases = Values.size();
// 40% is the default density for building a jump table in optsize/minsize mode.
// 40% is the default density for building a jump table in optsize/minsize
// mode.
uint64_t MinDensity = 40;
return NumCases * 100 >= Range * MinDensity;
@ -5538,11 +5539,11 @@ static bool ReduceSwitchRange(SwitchInst *SI, IRBuilder<> &Builder,
if (SI->getNumCases() < 4)
return false;
// This transform is agnostic to the signedness of the input or case values. We
// can treat the case values as signed or unsigned. We can optimize more common
// cases such as a sequence crossing zero {-4,0,4,8} if we interpret case values
// as signed.
SmallVector<int64_t,4> Values;
// This transform is agnostic to the signedness of the input or case values.
// We can treat the case values as signed or unsigned. We can optimize more
// common cases such as a sequence crossing zero {-4,0,4,8} if we interpret
// case values as signed.
SmallVector<int64_t, 4> Values;
for (auto &C : SI->cases())
Values.push_back(C.getCaseValue()->getValue().getSExtValue());
llvm::sort(Values);
@ -5563,9 +5564,9 @@ static bool ReduceSwitchRange(SwitchInst *SI, IRBuilder<> &Builder,
for (auto &V : Values)
GCD = GreatestCommonDivisor64(GCD, (uint64_t)V);
// This transform can be done speculatively because it is so cheap - it results
// in a single rotate operation being inserted. This can only happen if the
// factor extracted is a power of 2.
// This transform can be done speculatively because it is so cheap - it
// results in a single rotate operation being inserted. This can only happen
// if the factor extracted is a power of 2.
// FIXME: If the GCD is an odd number we can multiply by the multiplicative
// inverse of GCD and then perform this transform.
// FIXME: It's possible that optimizing a switch on powers of two might also