[WebAssembly] Degenerate case in vectorization of all true

[badumbatish]

I'm investigating #50142, trying to reduce any_true to all_true , reproducible example code gives this godbolt:

#include <stdint.h>

int all_true(uint8_t *a) {
    int8_t r = 1;
    for (int i = 0 ; i < 16 ; i++) {
        r &= !!a[i];
    }
    return r;
}

I changed int8_t r = 1 to int8_t r= 0, and r &= !!a[i] to r |= !!a[i] and the code degenerates completely (not even vectorized as any_true or all_true).

The godbolt link is here

[llvmbot]

@llvm/issue-subscribers-backend-webassembly

Author: jjasmine (badumbatish)

I'm investigating #50142, trying to reduce any_true to all_true , reproducible example code gives this [godbolt](https://godbolt.org/z/oze7dosYo): ```c #include <stdint.h>

int all_true(uint8_t *a) {
int8_t r = 1;
for (int i = 0 ; i < 16 ; i++) {
r &= !!a[i];
}
return r;
}

I changed `int8_t r = 1` to `int8_t r= 0`, and `r &= !!a[i]` to `r |= !!a[i]` and the code degenerates completely (not even vectorized as any_true or all_true).

The godbolt link is [here](https://godbolt.org/z/qcMPj1be9)
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