Fri, 29 Apr 1994 13:03:20 GMT

Related articles |
---|

Acceptable C optimizations? c5cx016@boe00.minc.umd.edu (Ed Finch) (1994-04-27) |

Re: Acceptable C optimizations? cts@stpb.soft.net (1994-04-29) |

Newsgroups: | comp.compilers |

From: | cts@stpb.soft.net (Celsius Tech) |

X-Organisation: | Software Technology Park, Bangalore |

Keywords: | C, optimize |

Organization: | Compilers Central |

References: | 94-04-173 |

Date: | Fri, 29 Apr 1994 13:03:20 GMT |

*>[ When is it OK to in-line "strcpy(x,"HelloWorld");" or*

*> memset(x,0,sizeof(x)); ?]*

In both the cases you are assuming that the number of bytes to be copied

is constant. In fact the problem is a special case of inlining intrinsic

functions.

If it is known that the functions have predefined meaning, as understood

by the compiler, you can inline such functions. As a special case one can

do the optimizations described above.

Most of the comercial compilers I came across provide "# pragma intrinsic"

or option to allow user specify such optimization. The functions which are

inlined not only include string and memory functions but also some

mathematical functions. Most of the mathematical function implementations

are side-effect free and so when the floating point hardware is present

(which support such functions) inlining of such functions is helpful.

-- Vivek (cts@stpb.soft.net)

--

Post a followup to this message

Return to the
comp.compilers page.

Search the
comp.compilers archives again.