Windows: SMT halves L1i/L1d/L2 cache instance count (cache.processor_count doubled)

[Yassin-pixel-bit]

On AMD Ryzen CPUs with SMT , cpuinfo_get_l1i_caches_count() / cpuinfo_get_l1d_caches_count() / cpuinfo_get_l2_caches_count() return half the expected number of cache instances on Windows, with each instance's processor_count doubled. the single core cache size comes out correct.
I also tested on an Intel CPU, though without hyper-threading and the total cache sizes came out correct.

Environment:

cpuinfo: main branch, fetched via CMake FetchContent, rebuilt today
Compiler: GCC/GNU 15.2.0 (MinGW-w64)
OS: Windows 11, fully updated (same binary tested across all three machines)

I tested this in three different devices

1st device:
CPU: AMD Ryzen 7 260 (8 cores / 16 threads)

results:

name: AMD Ryzen 7 260
ARCH: x86_64 (64-bit)
physical cores: 8
Logical threads: 16

l1i single core: 32 KB
l1d single core: 32 KB
l2 single core: 1024 KB

L1i[0] size=32768 processor_start=0 processor_count=4
L1i[1] size=32768 processor_start=4 processor_count=4
L1i[2] size=32768 processor_start=8 processor_count=4
L1i[3] size=32768 processor_start=12 processor_count=4

l1 cache total: 256 KB
l2 cache total: 4096 KB
l3 cache total: 16384 KB
l4 cache total: NaN

2nd device:
CPU: AMD Ryzen 3 5300U (4 cores / 8 threads)

results:

name: AMD Ryzen 3 5300U
ARCH: x86_64 (64-bit)
physical cores: 4
Logical threads: 8

l1i single core: 32 KB
l1d single core: 32 KB
l2 single core: 512 KB

L1i[0] size=32768 processor_start=0 processor_count=4
L1i[1] size=32768 processor_start=4 processor_count=4

l1 cache total: 128 KB
l2 cache total: 1024 KB
l3 cache total: 4096 KB
l4 cache total: NaN

3rd device (correct output):
CPU: Intel Core i7-9700K (8 cores / 8 threads)

results:

name: Intel Core i7-9700K
ARCH: x86_64 (64-bit)
physical cores: 8
Logical threads: 8

l1i single core: 32 KB
l1d single core: 32 KB
l2 single core: 256 KB

L1i[0] size=32768 processor_start=0 processor_count=1
L1i[1] size=32768 processor_start=1 processor_count=1
L1i[2] size=32768 processor_start=2 processor_count=1
L1i[3] size=32768 processor_start=3 processor_count=1
L1i[4] size=32768 processor_start=4 processor_count=1
L1i[5] size=32768 processor_start=5 processor_count=1
L1i[6] size=32768 processor_start=6 processor_count=1
L1i[7] size=32768 processor_start=7 processor_count=1

l1 cache total: 512 KB
l2 cache total: 2048 KB
l3 cache total: 12288 KB
l4 cache total: NaN

bug.cpp