83 lines
1.9 KiB
C
83 lines
1.9 KiB
C
/* $Header$ */
|
|
/*
|
|
* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
|
|
* See the copyright notice in the ACK home directory, in the file "Copyright".
|
|
*/
|
|
|
|
/* C O M M O N S U B E X P R E S S I O N E L I M I N A T I O N */
|
|
|
|
|
|
#include <stdio.h>
|
|
#include "../share/types.h"
|
|
#include "../share/lset.h"
|
|
#include "../share/debug.h"
|
|
#include "../share/go.h"
|
|
#include "cs.h"
|
|
#include "cs_aux.h"
|
|
#include "cs_avail.h"
|
|
#include "cs_debug.h"
|
|
#include "cs_elim.h"
|
|
#include "cs_entity.h"
|
|
#include "cs_profit.h"
|
|
#include "cs_stack.h"
|
|
#include "cs_vnm.h"
|
|
|
|
int Scs; /* Number of optimizations found. */
|
|
|
|
STATIC cs_clear()
|
|
{
|
|
clr_avails();
|
|
clr_entities();
|
|
clr_stack();
|
|
|
|
start_valnum();
|
|
}
|
|
|
|
STATIC cs_optimize(p)
|
|
proc_p p;
|
|
{
|
|
/* Optimize all basic blocks of one procedure. */
|
|
|
|
register bblock_p rbp, bdone;
|
|
|
|
avails = (avail_p) 0;
|
|
entities = Lempty_set();
|
|
cs_clear();
|
|
|
|
rbp = p->p_start;
|
|
|
|
while (rbp != (bblock_p) 0) {
|
|
/* First we build a list of common expressions with the
|
|
* value numbering algorithm. We take blocks in textual order
|
|
* as long as the next block can only be reached through the
|
|
* block we have just done. Note that if a block is preceded
|
|
* by itself, the number of predecessors is greater than 1,
|
|
* but the previous block can still be its immediate dominator.
|
|
*/
|
|
do { vnm(rbp); bdone = rbp;
|
|
OUTTRACE("basic block %d processed", bdone->b_id);
|
|
rbp = rbp->b_next;
|
|
} while (rbp != (bblock_p) 0 && rbp->b_idom == bdone &&
|
|
Lnrelems(rbp->b_pred) == 1
|
|
);
|
|
OUTTRACE("value numbering completed", 0);
|
|
OUTAVAILS(); OUTENTITIES();
|
|
|
|
/* Now we put out the instructions without common
|
|
* subexpressions but with the use of temporaries,
|
|
* which will be local variables of procedure p.
|
|
*/
|
|
eliminate(p);
|
|
cs_clear();
|
|
}
|
|
}
|
|
|
|
main(argc, argv)
|
|
int argc;
|
|
char *argv[];
|
|
{
|
|
Scs = 0;
|
|
go(argc, argv, no_action, cs_optimize, cs_machinit, no_action);
|
|
report("Duplicate expressions eliminated", Scs);
|
|
exit(0);
|
|
}
|