Clang C++ new operator large dynamic array slow compile time - c++

Question

I am facing a very unusual issue using clang-1200.0.32.21 on Mac OS Catalina 10.15.7.
Essentially, this code takes a long time to compile, and has extremely high RAM usage (peeks around 10GB of RAM):
m_Table = new MapGenerator::Block[MAP_DIAMETER * MAP_HEIGHT * MAP_DIAMETER]();
===-------------------------------------------------------------------------===
Clang front-end time report
===-------------------------------------------------------------------------===
Total Execution Time: 50.8973 seconds (55.3352 wall clock)
---User Time--- --System Time-- --User+System-- ---Wall Time--- --- Name ---
34.9917 (100.0%) 15.9056 (100.0%) 50.8973 (100.0%) 55.3352 (100.0%) Clang front-end timer
34.9917 (100.0%) 15.9056 (100.0%) 50.8973 (100.0%) 55.3352 (100.0%) Total
Changing it to the following instantly fixes it:
uint32_t table_size = Map::MAP_DIAMETER * Map::MAP_HEIGHT * Map::MAP_DIAMETER * sizeof(MapGenerator::Block);
m_Table = reinterpret_cast<MapGenerator::Block*>(malloc(table_size));
memset(m_Table, 0, table_size);
===-------------------------------------------------------------------------===
Clang front-end time report
===-------------------------------------------------------------------------===
Total Execution Time: 1.3105 seconds (2.1116 wall clock)
---User Time--- --System Time-- --User+System-- ---Wall Time--- --- Name ---
1.1608 (100.0%) 0.1497 (100.0%) 1.3105 (100.0%) 2.1116 (100.0%) Clang front-end timer
1.1608 (100.0%) 0.1497 (100.0%) 1.3105 (100.0%) 2.1116 (100.0%) Total
If you are curious, these are the relevant definitions:
enum : int { MAP_HEIGHT = 15 };
enum : int { MAP_DIAMETER = 1000 };
union Block
{
struct
{
uint8_t valid : 1; // block valid
/* used to determine visible faces */
uint8_t v_top : 1;
uint8_t v_bottom : 1;
uint8_t v_front : 1;
uint8_t v_back : 1;
uint8_t v_right : 1;
uint8_t v_left : 1;
uint8_t v_base : 1;
uint8_t discard : 1; // delete flag
};
uint16_t bits;
};
Block* m_Table;
Is there any logical reason as to why new takes this long to compile? To my understanding it should not be different. Also, I do not have this issue on the MSVC (Microsoft C++) compiler on Windows.
EDIT:
This is a minimal reproducible sample:
#include <cstdint>
#include <cstdlib>
#include <cstring>
enum : int { MAP_HEIGHT = 15 };
enum : int { MAP_DIAMETER = 1000 };
union Block
{
struct
{
uint8_t valid : 1; // block valid
/* used to determine visible faces */
uint8_t v_top : 1;
uint8_t v_bottom : 1;
uint8_t v_front : 1;
uint8_t v_back : 1;
uint8_t v_right : 1;
uint8_t v_left : 1;
uint8_t v_base : 1;
uint8_t discard : 1; // delete flag
};
uint16_t bits;
};
Block* table = nullptr;
// UNCOMMENT THIS:
// #define USE_MALLOC
int main(int argc, char* argv[])
{
#ifndef USE_MALLOC
table = new Block[MAP_DIAMETER * MAP_HEIGHT * MAP_DIAMETER]();
#else
uint32_t table_size = MAP_DIAMETER * MAP_HEIGHT * MAP_DIAMETER * sizeof(Block);
table = reinterpret_cast<Block*>(malloc(table_size));
memset(table, 0, table_size);
#endif
(void) table;
#ifndef USE_MALLOC
delete[] table;
#else
free(table);
#endif
return 0;
}
I compile it with the command:
g++ -std=c++17 -g -Wall -Werror -ftime-report -c test.cpp -o test.o