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view tests/mini/union5.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> |
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date | Tue, 28 Apr 2009 21:58:06 +0200 |
parents | 44f08170f4ef |
children |
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module union5; union S { T t; U u; uint i; struct { ushort sl,sh; } } struct T { int i; } struct U { float f; } void main() { S s; assert(s.t.i == 0); assert(s.u.f == 0); s.t.i = -1; assert(s.i == 0xFFFF_FFFF); float f = 3.1415; s.u.f = f; uint pi = *cast(uint*)&f; assert(s.i == pi); assert(s.sl == (pi&0xFFFF)); assert(s.sh == (pi>>>16)); }