https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120022
Jin Haobo <a1343922569 at outlook dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|WONTFIX |---
Status|RESOLVED |UNCONFIRMED
--- Comment #4 from Jin Haobo <a1343922569 at outlook dot com> ---
(In reply to Andrew Pinski from comment #1)
> Note your inline-asm is still broken.
>
> asm (
> "xor %[remainder], %[remainder] \n\t"
> "div %[divisor] \n\t"
> : [quotient] "=a"(result), [remainder] "=&d" (dummyRemainder)
> : [dividendLow] "a"(a), [divisor] "rm"(b)
> );
>
> Is the corrected version. The reason you need an early clobber on remainder
> output is because you clobber it before use the input of divisor and divisor
> still can be assigned to rdx.
Thank you, but the "correct" code still generate suboptimal assembly code for
myDivMod1, while Clang is optimal.
GCC: https://gcc.godbolt.org/z/cvadddsz3
Clang: https://gcc.godbolt.org/z/fdvaWzGo5
Is this actually a suboptimal assembly, or I miss some subtle detail?
