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[Support] Use CTLog2 from PointerLikeTypeTraits.h (NFC) #157790

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Merged
merged 1 commit into from
Sep 10, 2025
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[Support] Use CTLog2 from PointerLikeTypeTraits.h (NFC) #157790

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2 changes: 1 addition & 1 deletion clang/include/clang/AST/Expr.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1038,7 +1038,7 @@ class Expr : public ValueStmt {
// PointerLikeTypeTraits is specialized so it can be used with a forward-decl of
// Expr. Verify that we got it right.
static_assert(llvm::PointerLikeTypeTraits<Expr *>::NumLowBitsAvailable <=
llvm::detail::ConstantLog2<alignof(Expr)>::value,
llvm::CTLog2<alignof(Expr)>(),
"PointerLikeTypeTraits<Expr*> assumes too much alignment.");

using ConstantExprKind = Expr::ConstantExprKind;
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14 changes: 3 additions & 11 deletions llvm/include/llvm/Support/PointerLikeTypeTraits.h
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Original file line number Diff line number Diff line change
Expand Up @@ -15,8 +15,8 @@
#define LLVM_SUPPORT_POINTERLIKETYPETRAITS_H

#include "llvm/Support/DataTypes.h"
#include "llvm/Support/MathExtras.h"
#include <cassert>
#include <type_traits>

namespace llvm {

Expand All @@ -25,12 +25,6 @@ namespace llvm {
template <typename T> struct PointerLikeTypeTraits;

namespace detail {
/// A tiny meta function to compute the log2 of a compile time constant.
template <size_t N>
struct ConstantLog2
: std::integral_constant<size_t, ConstantLog2<N / 2>::value + 1> {};
template <> struct ConstantLog2<1> : std::integral_constant<size_t, 0> {};

// Provide a trait to check if T is pointer-like.
template <typename T, typename U = void> struct HasPointerLikeTypeTraits {
static const bool value = false;
Expand All @@ -57,8 +51,7 @@ template <typename T> struct PointerLikeTypeTraits<T *> {
static inline void *getAsVoidPointer(T *P) { return P; }
static inline T *getFromVoidPointer(void *P) { return static_cast<T *>(P); }

static constexpr int NumLowBitsAvailable =
detail::ConstantLog2<alignof(T)>::value;
static constexpr int NumLowBitsAvailable = CTLog2<alignof(T)>();
};

template <> struct PointerLikeTypeTraits<void *> {
Expand Down Expand Up @@ -123,8 +116,7 @@ template <> struct PointerLikeTypeTraits<uintptr_t> {
/// potentially use alignment attributes on functions to satisfy that.
template <int Alignment, typename FunctionPointerT>
struct FunctionPointerLikeTypeTraits {
static constexpr int NumLowBitsAvailable =
detail::ConstantLog2<Alignment>::value;
static constexpr int NumLowBitsAvailable = CTLog2<Alignment>();
static inline void *getAsVoidPointer(FunctionPointerT P) {
assert((reinterpret_cast<uintptr_t>(P) &
~((uintptr_t)-1 << NumLowBitsAvailable)) == 0 &&
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