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view lphobos/std/intrinsic.d @ 1275:bedf0bfb8fdb
Implement first D-specific optimization pass: -simplify-drtcalls.
It uses the machinery of the standard -simplify-libcalls pass, but optimizes
calls to the D runtime instead of calls to C libraries.
At the moment, these optimizations are implemented by this pass:
- Avoid the runtime call for `arr.length = newlen` if it can determine that
the new length isn't longer than the old one.
- Ditto for `cast(T[]) arr` if it will clearly always succeed.
(e.g. if the length of the original array is zero, or if the old element
size is a multiple of the new element size)
author | Frits van Bommel <fvbommel wxs.nl> |
---|---|
date | Tue, 28 Apr 2009 21:58:06 +0200 |
parents | eef8ac26c66c |
children |
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// written by Walter Bright // www.digitalmars.com // Placed into the public domain /* NOTE: This file has been patched from the original DMD distribution to work with the GDC compiler. NOTE: This file has been patched from the original GDC distribution to work with the LDC compiler. Modified by David Friedman, May 2006 Modified by Tomas Lindquist Olsen, August 2007 */ /** These functions are built-in intrinsics to the compiler. * Intrinsic functions are functions built in to the compiler, usually to take advantage of specific CPU features that are inefficient to handle via external functions. The compiler's optimizer and code generator are fully integrated in with intrinsic functions, bringing to bear their full power on them. This can result in some surprising speedups. * Macros: * WIKI=Phobos/StdIntrinsic */ module std.intrinsic; /** * Scans the bits in v starting with bit 0, looking * for the first set bit. * Returns: * The bit number of the first bit set. * The return value is undefined if v is zero. */ version (LLVM) int bsf(uint v) { uint m = 1; uint i; for (i = 0; i < 32; i++,m<<=1) { if (v&m) return i; } return i; // supposed to be undefined } else int bsf(uint v); /** * Scans the bits in v from the most significant bit * to the least significant bit, looking * for the first set bit. * Returns: * The bit number of the first bit set. * The return value is undefined if v is zero. * Example: * --- * import std.intrinsic; * * int main() * { * uint v; * int x; * * v = 0x21; * x = bsf(v); * printf("bsf(x%x) = %d\n", v, x); * x = bsr(v); * printf("bsr(x%x) = %d\n", v, x); * return 0; * } * --- * Output: * bsf(x21) = 0<br> * bsr(x21) = 5 */ version (LLVM) int bsr(uint v) { uint m = 0x80000000; uint i; for (i = 32; i ; i--,m>>>=1) { if (v&m) return i-1; } return i; // supposed to be undefined } else int bsr(uint v); /** * Tests the bit. */ version (LLVM) int bt(uint *p, uint bitnum) { return (p[bitnum / (uint.sizeof*8)] & (1<<(bitnum & ((uint.sizeof*8)-1)))) ? -1 : 0 ; } else int bt(uint *p, uint bitnum); /** * Tests and complements the bit. */ version (LLVM) int btc(uint *p, uint bitnum) { uint * q = p + (bitnum / (uint.sizeof*8)); uint mask = 1 << (bitnum & ((uint.sizeof*8) - 1)); int result = *q & mask; *q ^= mask; return result ? -1 : 0; } else int btc(uint *p, uint bitnum); /** * Tests and resets (sets to 0) the bit. */ version (LLVM) int btr(uint *p, uint bitnum) { uint * q = p + (bitnum / (uint.sizeof*8)); uint mask = 1 << (bitnum & ((uint.sizeof*8) - 1)); int result = *q & mask; *q &= ~mask; return result ? -1 : 0; } else int btr(uint *p, uint bitnum); /** * Tests and sets the bit. * Params: * p = a non-NULL pointer to an array of uints. * index = a bit number, starting with bit 0 of p[0], * and progressing. It addresses bits like the expression: --- p[index / (uint.sizeof*8)] & (1 << (index & ((uint.sizeof*8) - 1))) --- * Returns: * A non-zero value if the bit was set, and a zero * if it was clear. * * Example: * --- import std.intrinsic; int main() { uint array[2]; array[0] = 2; array[1] = 0x100; printf("btc(array, 35) = %d\n", <b>btc</b>(array, 35)); printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]); printf("btc(array, 35) = %d\n", <b>btc</b>(array, 35)); printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]); printf("bts(array, 35) = %d\n", <b>bts</b>(array, 35)); printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]); printf("btr(array, 35) = %d\n", <b>btr</b>(array, 35)); printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]); printf("bt(array, 1) = %d\n", <b>bt</b>(array, 1)); printf("array = [0]:x%x, [1]:x%x\n", array[0], array[1]); return 0; } * --- * Output: <pre> btc(array, 35) = 0 array = [0]:x2, [1]:x108 btc(array, 35) = -1 array = [0]:x2, [1]:x100 bts(array, 35) = 0 array = [0]:x2, [1]:x108 btr(array, 35) = -1 array = [0]:x2, [1]:x100 bt(array, 1) = -1 array = [0]:x2, [1]:x100 </pre> */ version (LLVM) int bts(uint *p, uint bitnum) { uint * q = p + (bitnum / (uint.sizeof*8)); uint mask = 1 << (bitnum & ((uint.sizeof*8) - 1)); int result = *q & mask; *q |= mask; return result ? -1 : 0; } else int bts(uint *p, uint bitnum); /** * Swaps bytes in a 4 byte uint end-to-end, i.e. byte 0 becomes byte 3, byte 1 becomes byte 2, byte 2 becomes byte 1, byte 3 becomes byte 0. */ version (LLVM) pragma(intrinsic, "llvm.bswap.i32") uint bswap(uint val); else uint bswap(uint v); /** * Reads I/O port at port_address. */ version (LLVM) ubyte inp(uint p) { return 0; } else ubyte inp(uint port_address); /** * ditto */ version (LLVM) ushort inpw(uint p) { return 0; } else ushort inpw(uint port_address); /** * ditto */ version (LLVM) uint inpl(uint p) { return 0; } else uint inpl(uint port_address); /** * Writes and returns value to I/O port at port_address. */ version (LLVM) ubyte outp(uint p, ubyte v) { return v; } else ubyte outp(uint port_address, ubyte value); /** * ditto */ version (LLVM) ushort outpw(uint p, ushort v) { return v; } else ushort outpw(uint port_address, ushort value); /** * ditto */ version (LLVM) uint outpl(uint p, uint v) { return v; } else uint outpl(uint port_address, uint value);