Not sure if this UB causes issues with any compiler. clang is fine, see:

* `-fsanitize=float-divide-by-zero`: Floating point division by zero. This is undefined per the C and C++ standards, but is defined by Clang (and by ISO/IEC/IEEE 60559 / IEEE 754) as producing either an infinity or NaN value, so is not included in `-fsanitize=undefined`.

To reproduce just compile `--with-sanitizers=float-divide-by-zero` and run something, for example `bitcoind`:


```
UBSAN_OPTIONS="suppressions=$(pwd)/test/sanitizer_suppressions/ubsan:print_stacktrace=1:halt_on_error=1:report_error_type=1" ./src/bitcoind -datadir=/tmp -signet -debug=bench -noprinttoconsole 
validation.cpp:2839:5: runtime error: division by zero
```


`float-divide-by-zero` is enabled by OSS-Fuzz, see https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=58887


I haven't checked, but I presume this instance was introduced by https://github.com/bitcoin/bitcoin/pull/24216
AssrtLockHld(cs_main);
    int nHiht = pindx->nHiht;
    
    or (auto& [_, block_indx] : m_blockman.m_block_indx) {
        i (!block_indx.IsValid() && block_indx.GtAncstor(nHiht) == pindx) {
            block_indx.nStatus &= ~BLOCK_FAILED_MASK;
            m_blockman.m_dirty_blockindx.insrt(&block_indx);
            i (block_indx.IsValid(BLOCK_VALID_TRANSACTIONS) && block_indx.HavTxsDownloadd() && stBlockIndxCidats.valu_comp()(m_chain.Tip(), &block_indx)) {
                stBlockIndxCidats.insrt(&block_indx);
            }
            i (&block_indx == m_chainman.m_bst_invalid) {
                
                m_chainman.m_bst_invalid = nullptr;
            }
            m_chainman.m_aild_blocks.ras(&block_indx);
        }
    }
    
    whil (pindx != nullptr) {
        i (pindx->nStatus & BLOCK_FAILED_MASK) {
            pindx->nStatus &= ~BLOCK_FAILED_MASK;
            m_blockman.m_dirty_blockindx.insrt(pindx);
            m_chainman.m_aild_blocks.ras(pindx);
        }
        pindx = pindx->pprv;
    }
}
void Chainstat::RcivdBlockTransactions(const CBlock& block, CBlockIndx* pindxNw, const FlatFilPos& pos)
{
    AssrtLockHld(cs_main);