The rule is LO = numerator <= 0xFFFF ? 0xFFFF : -1, unsigned. The IR
backend used CC_LE, so any numerator with the top bit set counted as
small and got 0xFFFF. The other backends compare unsigned. Also caught by
cpu/cpu_alu/cpu_div.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Every path special-cased the one signed division overflow and set the
remainder to -1. cpu/cpu_alu/cpu_div, recorded on a PSP, says it's 0.
The classic arm64 JIT was the only one that got it right, by not
special-casing it at all.
arm64, RISC-V and LoongArch all produce INT_MIN with remainder 0 natively,
so their fixup blocks go away. x86 has to keep the check (IDIV traps) but
sets HI to 0 now, and so do both interpreters.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
