Why don't you test it and find out yourself?
On Tue, Mar 11, 2025 at 10:20 AM Sỹ Trần Dũng <sytranc...@gmail.com> wrote: > I have a question regarding V8's compiler optimization, specifically > concerning the modulo 2 operation. In compilers like GCC and Clang, it's > common to see the operation n % 2 optimized to a bitwise AND (n & 1) or a > bit check instruction, as these are generally more efficient. > > I've been examining the bytecode generated by V8, and I've observed that a > modulo instruction is used for n % 2. > > [generated bytecode for function: my_mod (0x3de244c5b401 > <SharedFunctionInfo my_mod>)] > Bytecode length: 17 > Parameter count 2 > Register count 1 > Frame size 8 > 23 S> 0x32c69b60dc80 @ 0 : 0b 03 Ldar a0 > 29 E> 0x32c69b60dc82 @ 2 : 4b 02 00 ModSmi [2], [0] > 0x32c69b60dc85 @ 5 : c9 Star0 > 0x32c69b60dc86 @ 6 : 0d 01 LdaSmi [1] > 33 E> 0x32c69b60dc88 @ 8 : 6f f9 01 TestEqual r0, [1] > 0x32c69b60dc8b @ 11 : 9e 04 JumpIfFalse [4] > (0x32c69b60dc8f @ 15) > 45 S> 0x32c69b60dc8d @ 13 : 11 LdaTrue > 57 S> 0x32c69b60dc8e @ 14 : ae Return > 64 S> 0x32c69b60dc8f @ 15 : 12 LdaFalse > 77 S> 0x32c69b60dc90 @ 16 : ae Return > > I'm curious if this behavior changes when the code is "heated" and > optimized by Turbofan. > > Could someone please tell whether Turbofan performs this particular > optimization? > > Thank you for your time and expertise. > > -- > -- -- v8-dev mailing list v8-dev@googlegroups.com http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-dev+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/v8-dev/CAKSzg3RMAwVP34-A2yRPsg3zDjkM1AMCfouQi%3DsPWmaSeKALpg%40mail.gmail.com.
