| ??? 05/05/08 19:11 Modified: 05/05/08 19:58 Read: times |
#154443 - Compiler-independent efficient C Responding to: ???'s previous message |
Erik said:
do recall some long ago doing checks of a) and b) where b), indeed, "made it easier for the compiler" what they were is long forgotten Sure. With a compiler that's not too bright about optimization, you could/can help things along with simple tricks like changing (a * 8) to (a << 3), or removing unvarying calculations from loops. But as compilers get better and better, those tricks have less and less value because the compiler does those things for you anyway, regardless of how you write your program. Erik said:
so, maybe we should forget about the compilers involvement and just continue with "compiler independent efficient C" But what does that mean? Is there any such thing? Do you really mean "compiler dependent efficient C"? After trying and failing to come up with some illustrative examples, I'm starting to think that "compiler independent efficient C" is just "C", and that the success of any attempt you make to write in a way that improves the generated code is going to depend on which compiler you're using. -- Russ |
| Topic | Author | Date |
| "Real C" vs '51 C | 01/01/70 00:00 | |
| there is nothing wrong except... | 01/01/70 00:00 | |
| if you are not , why are you even here | 01/01/70 00:00 | |
| *(buffer+8+index)? | 01/01/70 00:00 | |
| none of the above | 01/01/70 00:00 | |
| OK then how? | 01/01/70 00:00 | |
| like this | 01/01/70 00:00 | |
| but it's basically the same... | 01/01/70 00:00 | |
| YCMV | 01/01/70 00:00 | |
| No | 01/01/70 00:00 | |
| assumptions | 01/01/70 00:00 | |
| Re: assumptions | 01/01/70 00:00 | |
| I took a \'known\' example | 01/01/70 00:00 | |
| Compiler-independent efficient C | 01/01/70 00:00 | |
| a clarification and an example | 01/01/70 00:00 | |
| Two kinds of "efficiency" | 01/01/70 00:00 | |
| Compiler smarter than coder | 01/01/70 00:00 | |
| Getting the least out of your compiler | 01/01/70 00:00 | |
| Real C is inherently reentrant | 01/01/70 00:00 | |
which, even when possible, often is ill advised | 01/01/70 00:00 |