GCC ignores `-mcpu=arm7tdmi` flag and generates unsupported instruction

I'm trying to compile a small program for arm7tdmi (i.e. armv4t), using the command arm-linux-gnueabi-gcc -march=armv4t -mcpu=arm7tdmi -nostartfiles -static test.c -o test on Debian (gcc version 10.2.1, Debian 10.2.1-6). However, GCC seems to ignore the cpu and arch flags, and generates instructions that are unsupported on armv4t, e.g. clz, as shown by objdump:

   104f4:       0a000071        beq     106c0 <.divsi3_skip_div0_test+0x1f0>   104f8:       e16f2f13        clz     r2, r3   104fc:       e16f0f11        clz     r0, r1   10500:       e0402002        sub     r2, r0, r2   10504:       e272201f        rsbs    r2, r2, #31

I also checked the binary using readelf, and it shows the architecture is actually armv5te:

File Attributes  Tag_CPU_name: "5TE"  Tag_CPU_arch: v5TE  Tag_ARM_ISA_use: Yes  Tag_THUMB_ISA_use: Thumb-1

May I ask what's going on here? Why is GCC ignoring the -mcpu and -march flags?

Here's the content of test.c:

#include <stdint.h>#include <stddef.h>void _start() {        const size_t len = 8;        uint8_t arr[8] = {10, 12, 8, 5, 0, 2, 3, 55};        uint8_t *data = arr;        uint16_t a = 1, b = 0, m = 7;        for(int i=0; i<len; i++) {                a = (a + data[i]) % m;                b = (a + b) % m;        }        uint32_t res = (uint32_t)b << 16 | (uint32_t)a;}