Hi Andrew, > Isn't [(1 << 31)] UB on a 32-bit machine as well? Looks like integer overflow to me. You know... I'm not sure. I thought (1 << 31) was defined behavior on 2's and 1's complement machines. I was an assembly bit-twiddler (6502, 65816, 680x0, and just a little bit of 80x86) back in the 70's and 80's (and some Alpha, PowerPC, and SPARC in the 90's... but not enough to brag about), so I tend to think in rather skewed terms (e.g., I think of C as a powerful macro assembler). But now that you brought it up*, I can't say that with strong confidence. I'll have to research C (ISO 9899) and C++ (ISO 14882). * Given the recent discussion about certain optimizations which perform compilation analysis and do certain /a priori/ compiler knowledge range optimizations based on UB that were a surprised** to the developer (the "surprise" fixed by -fwrapv). ** And also news to me. Good to be aware of the issue, although I am not aware of having been stung by it. Yet. Sincerely, --Eljay
