================
@@ -63,31 +64,49 @@ class TypeInfoLValue {
/// Symbolic representation of a dynamic allocation.
class DynamicAllocLValue {
- unsigned Index;
+public:
+ static constexpr int NumLowBitsAvailable = 2;
+ static constexpr int NumAlignmentBits = 5;
+
+private:
+ // lower NumAlignmentBits: alignment exponent
+ // remaining bits: allocation index incremented by one
+ // value of zero indicates distinct empty state
+ uintptr_t Align : NumAlignmentBits;
+ uintptr_t Index : sizeof(uintptr_t) * CHAR_BIT - NumAlignmentBits;
public:
- DynamicAllocLValue() : Index(0) {}
- explicit DynamicAllocLValue(unsigned Index) : Index(Index + 1) {}
- unsigned getIndex() { return Index - 1; }
+ DynamicAllocLValue() : Align(0), Index(0) {}
+ explicit DynamicAllocLValue(unsigned Idx, uint64_t Align)
+ : Align(llvm::countr_zero(Align)), Index(Idx + 1) {
+ assert(Align > 0 && "Invalid alignment for DynamicAllocLValue
constructor");
----------------
tbaederr wrote:
As for assertions, I guess it would make sense to assert that `Align` is a
power of 2 and that `llvm::countr_zero(Align)` actually fits into the 2 bits we
have for it.
https://github.com/llvm/llvm-project/pull/174549
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