taken from https://www.valvers.com/open-software/raspberry-pi/bare-metal-programming-in-c-part-1/

pi1: -mfpu=vfp -march=armv6zk -mtune=arm1176jzf-s
pi2: -mfpu=neon-vfpv4 -march=armv7-a -mtune=cortex-a7
pi3: -mfpu=crypto-neon-fp-armv8 -march=armv8-a+crc -mcpu=cortex-a53
pi4: -mfpu=crypto-neon-fp-armv8 -march=armv8-a+crc -mcpu=cortex-a72

gathered from pi's i own:

pi0/pi1:
SoC serial# 0x230aad04
HW revision: 0x0000000e
MIDR: 0x410FB767
armv6 cache type: 0x1d152152
L1i: words: 2, assoc: 2, size: 5, size2: 0
L1d: words: 2, assoc: 2, size: 5, size2: 0
S: 1
CType: 14
8 words per line
4 way associative
16kb each

pi2:
SoC serial# 0x1077df95
HW revision: 0x00a21041
  Type: 4
  Rev: 1
  Proc: 1
  Manufacturer: 2
  Ram: 2
MIDR: 0x410FC075
name    size    encoding        WT      WB      RA      WA      Sets    Assoc   LineSize
L1d     32 KB   0x700fe01a      0       1       1       1       0x7f    0x3     0x2(64 bytes)
L1i     32 KB   0x203fe009      0       0       1       0       0x1ff   0x1     0x1(32 bytes)
L2      512 KB  0x707fe03a      0       1       1       1       0x3ff   0x7     0x2(64 bytes)


pi3:
SoC serial# 0x9080d9b6
HW revision: 0x00a22082
  Type: 8
  Rev: 2
  Proc: 2
  Manufacturer: 2
  Ram: 2
MIDR: 0x410fd034
name    size    encoding        WT      WB      RA      WA      Sets    Assoc   LineSize
L1d     32 KB   0x700fe01a      0       1       1       1       0x7f    0x3     0x2(64 bytes)
L1i     32 KB   0x201fe00a      0       0       1       0       0xff    0x1     0x2(64 bytes)
L2      512 KB  0x703fe07a      0       1       1       1       0x1ff   0xf     0x2(64 bytes)