Just some simple tests of well known optimizations...
One thing that i really like is tail-recursion being -at last!- handled
| gcc | gcc | gcc |visual |
cc |
| 2.8.0 |2.95.3 | 2.96 | 5.0
|4.2-spa|
--------------------------------------------------|-------|-------|-------|-------|-------|
register allocation for local variables | 6 | 1 | 1 | 5 |
X |
register allocation for global variables | 8 | 5 | 1 | 5 |
X |
register allocation for function parameters | | 1 | 1 | |
X |
empty loop (static true exit condition) | X | X | X | X |
X |
one loop | X | . | X | |
|
aliasing handling with local pointer | X | X | X | X |
X |
aliasing handling with extern pointer aliased loca| X | X | X | X |
X |
aliasing handling with extern pointer aliased exte| X | X | X | X |
|
aliasing handling with extern pointer aliased exte| | | | X |
X |
(!) aliasing handling with extern pointer aliased | | | | X |
|
simple loop invariant code motion | X | X | X | . |
X |
complex loop invariant code motion | | X | X | |
. |
loop invariant code motion | X | X | X | . |
. |
simple code in loop indepedent from loop indice | | | | . |
|
complex code in loop indepedent from loop indice | | | | . |
|
very simple code in loop indepedent from loop indi| | | | X |
|
simple loop unrolling | X | X | X | X |
|
complex loop unrolling (needs algebraic simplifica| X | X | X | X |
|
hoisting | X | X | X | X |
X |
propagating test information in branches | X | X | X | X |
|
simple algebraic simplification | X | X | X | X |
X |
simple algebraic simplification | X | X | X | X |
X |
simple algebraic simplification | X | X | X | X |
|
simple algebraic simplification (commutativity) | X | X | X | X |
X |
simple algebraic simplification (division) | | | | |
|
(!) simple algebraic simplification (division) | X | X | X | |
|
(!) simple algebraic simplification (division) | | | | |
|
simple algebraic simplification (division) | | | | |
|
complex algebraic simplification | X | X | X | X |
|
complex algebraic simplification | X | X | X | X |
|
complex algebraic simplification | . | . | . | . |
|
simple floating point simplification | X | X | . | X |
X |
simple floating point simplification | X | X | X | X |
X |
simple floating point simplification | X | X | X | X |
X |
simple floating point simplification | X | X | X | X |
|
simple floating point simplification (commutativit| | | X | X |
|
instruction scheduling (register dependencies) | | . | . | |
. |
instruction scheduling (avoid load delays) | | | | |
X |
instruction scheduling (avoid load delays) | | | X | |
X |
simple common sub-expression removing | X | X | X | X |
X |
complex common sub-expression removing | X | X | X | |
X |
partial common sub-expression removing | | | | |
|
partial common sub-expression removing | | | | |
|
loop-invariant code motion (unswitching) | | | | |
|
induction variables detection | X | X | X | X |
. |
leaf-routine optimization | X | X | X | X |
. |
tail-recursion removing | | | X | X |
X |
tail-call optimization | | | X | X |
|
use of registers for function call | | | | |
X |
tail-recursion removing | | | X | X |
X |
complete stuff: ftp://ftp.mandrakesoft.com/pub/pixel/c-optimizations.tar.bz2
