OK for anyone who is curious about this #Clang #compilerBug, I've set up a godbolt:

https://godbolt.org/z/bTvaEf9sq

Compare the assembler output from GCC, or from Clang version 18 and earlier, to that of Clang 19 and later. Can you spot where the issue is, without running? Hint: it's in how […]