mirror of
https://github.com/golang/go
synced 2024-10-04 14:41:25 -06:00
6d47de2f40
Simpler version of CL 13084043. R=ken2 CC=golang-dev https://golang.org/cl/13602045
741 lines
14 KiB
C
741 lines
14 KiB
C
// Derived from Inferno utils/6c/peep.c
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// http://code.google.com/p/inferno-os/source/browse/utils/6c/peep.c
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//
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// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
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// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
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// Portions Copyright © 1997-1999 Vita Nuova Limited
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// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
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// Portions Copyright © 2004,2006 Bruce Ellis
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// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
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// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
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// Portions Copyright © 2009 The Go Authors. All rights reserved.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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#include <u.h>
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#include <libc.h>
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#include "gg.h"
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#include "opt.h"
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#define REGEXT 0
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static void conprop(Flow *r);
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static void elimshortmov(Graph*);
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static int subprop(Flow*);
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static int copyprop(Graph*, Flow*);
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static int copy1(Adr*, Adr*, Flow*, int);
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static int copyas(Adr*, Adr*);
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static int copyau(Adr*, Adr*);
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static int copysub(Adr*, Adr*, Adr*, int);
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static uint32 gactive;
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// do we need the carry bit
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static int
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needc(Prog *p)
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{
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ProgInfo info;
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while(p != P) {
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proginfo(&info, p);
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if(info.flags & UseCarry)
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return 1;
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if(info.flags & (SetCarry|KillCarry))
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return 0;
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p = p->link;
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}
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return 0;
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}
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static Flow*
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rnops(Flow *r)
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{
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Prog *p;
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Flow *r1;
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if(r != nil)
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for(;;) {
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p = r->prog;
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if(p->as != ANOP || p->from.type != D_NONE || p->to.type != D_NONE)
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break;
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r1 = uniqs(r);
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if(r1 == nil)
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break;
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r = r1;
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}
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return r;
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}
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void
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peep(Prog *firstp)
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{
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Flow *r, *r1;
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Graph *g;
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Prog *p, *p1;
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int t;
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g = flowstart(firstp, sizeof(Flow));
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if(g == nil)
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return;
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gactive = 0;
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// byte, word arithmetic elimination.
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elimshortmov(g);
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// constant propagation
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// find MOV $con,R followed by
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// another MOV $con,R without
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// setting R in the interim
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for(r=g->start; r!=nil; r=r->link) {
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p = r->prog;
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switch(p->as) {
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case ALEAL:
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if(regtyp(&p->to))
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if(p->from.sym != S)
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if(p->from.index == D_NONE || p->from.index == D_CONST)
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conprop(r);
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break;
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case AMOVB:
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case AMOVW:
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case AMOVL:
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case AMOVSS:
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case AMOVSD:
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if(regtyp(&p->to))
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if(p->from.type == D_CONST)
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conprop(r);
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break;
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}
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}
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loop1:
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if(debug['P'] && debug['v'])
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dumpit("loop1", g->start, 0);
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t = 0;
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for(r=g->start; r!=nil; r=r->link) {
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p = r->prog;
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switch(p->as) {
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case AMOVL:
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case AMOVSS:
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case AMOVSD:
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if(regtyp(&p->to))
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if(regtyp(&p->from)) {
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if(copyprop(g, r)) {
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excise(r);
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t++;
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} else
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if(subprop(r) && copyprop(g, r)) {
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excise(r);
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t++;
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}
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}
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break;
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case AMOVBLZX:
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case AMOVWLZX:
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case AMOVBLSX:
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case AMOVWLSX:
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if(regtyp(&p->to)) {
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r1 = rnops(uniqs(r));
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if(r1 != nil) {
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p1 = r1->prog;
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if(p->as == p1->as && p->to.type == p1->from.type){
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p1->as = AMOVL;
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t++;
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}
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}
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}
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break;
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case AADDL:
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case AADDW:
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if(p->from.type != D_CONST || needc(p->link))
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break;
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if(p->from.offset == -1){
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if(p->as == AADDL)
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p->as = ADECL;
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else
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p->as = ADECW;
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p->from = zprog.from;
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break;
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}
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if(p->from.offset == 1){
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if(p->as == AADDL)
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p->as = AINCL;
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else
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p->as = AINCW;
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p->from = zprog.from;
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break;
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}
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break;
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case ASUBL:
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case ASUBW:
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if(p->from.type != D_CONST || needc(p->link))
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break;
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if(p->from.offset == -1) {
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if(p->as == ASUBL)
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p->as = AINCL;
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else
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p->as = AINCW;
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p->from = zprog.from;
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break;
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}
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if(p->from.offset == 1){
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if(p->as == ASUBL)
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p->as = ADECL;
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else
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p->as = ADECW;
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p->from = zprog.from;
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break;
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}
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break;
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}
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}
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if(t)
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goto loop1;
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// MOVSD removal.
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// We never use packed registers, so a MOVSD between registers
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// can be replaced by MOVAPD, which moves the pair of float64s
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// instead of just the lower one. We only use the lower one, but
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// the processor can do better if we do moves using both.
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for(r=g->start; r!=nil; r=r->link) {
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p = r->prog;
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if(p->as == AMOVSD)
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if(regtyp(&p->from))
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if(regtyp(&p->to))
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p->as = AMOVAPD;
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}
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flowend(g);
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}
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void
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excise(Flow *r)
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{
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Prog *p;
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p = r->prog;
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if(debug['P'] && debug['v'])
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print("%P ===delete===\n", p);
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p->as = ANOP;
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p->from = zprog.from;
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p->to = zprog.to;
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ostats.ndelmov++;
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}
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int
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regtyp(Adr *a)
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{
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int t;
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t = a->type;
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if(t >= D_AX && t <= D_DI)
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return 1;
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if(t >= D_X0 && t <= D_X7)
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return 1;
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return 0;
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}
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// movb elimination.
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// movb is simulated by the linker
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// when a register other than ax, bx, cx, dx
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// is used, so rewrite to other instructions
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// when possible. a movb into a register
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// can smash the entire 64-bit register without
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// causing any trouble.
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static void
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elimshortmov(Graph *g)
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{
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Prog *p;
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Flow *r;
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for(r=g->start; r!=nil; r=r->link) {
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p = r->prog;
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if(regtyp(&p->to)) {
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switch(p->as) {
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case AINCB:
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case AINCW:
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p->as = AINCL;
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break;
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case ADECB:
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case ADECW:
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p->as = ADECL;
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break;
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case ANEGB:
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case ANEGW:
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p->as = ANEGL;
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break;
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case ANOTB:
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case ANOTW:
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p->as = ANOTL;
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break;
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}
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if(regtyp(&p->from) || p->from.type == D_CONST) {
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// move or artihmetic into partial register.
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// from another register or constant can be movl.
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// we don't switch to 32-bit arithmetic if it can
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// change how the carry bit is set (and the carry bit is needed).
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switch(p->as) {
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case AMOVB:
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case AMOVW:
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p->as = AMOVL;
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break;
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case AADDB:
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case AADDW:
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if(!needc(p->link))
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p->as = AADDL;
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break;
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case ASUBB:
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case ASUBW:
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if(!needc(p->link))
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p->as = ASUBL;
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break;
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case AMULB:
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case AMULW:
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p->as = AMULL;
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break;
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case AIMULB:
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case AIMULW:
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p->as = AIMULL;
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break;
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case AANDB:
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case AANDW:
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p->as = AANDL;
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break;
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case AORB:
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case AORW:
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p->as = AORL;
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break;
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case AXORB:
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case AXORW:
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p->as = AXORL;
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break;
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case ASHLB:
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case ASHLW:
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p->as = ASHLL;
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break;
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}
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} else {
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// explicit zero extension
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switch(p->as) {
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case AMOVB:
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p->as = AMOVBLZX;
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break;
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case AMOVW:
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p->as = AMOVWLZX;
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break;
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}
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}
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}
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}
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}
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/*
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* the idea is to substitute
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* one register for another
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* from one MOV to another
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* MOV a, R0
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* ADD b, R0 / no use of R1
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* MOV R0, R1
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* would be converted to
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* MOV a, R1
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* ADD b, R1
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* MOV R1, R0
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* hopefully, then the former or latter MOV
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* will be eliminated by copy propagation.
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*/
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static int
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subprop(Flow *r0)
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{
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Prog *p;
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Adr *v1, *v2;
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Flow *r;
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int t;
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ProgInfo info;
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p = r0->prog;
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v1 = &p->from;
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if(!regtyp(v1))
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return 0;
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v2 = &p->to;
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if(!regtyp(v2))
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return 0;
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for(r=uniqp(r0); r!=nil; r=uniqp(r)) {
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if(debug['P'] && debug['v'])
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print("\t? %P\n", r->prog);
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if(uniqs(r) == nil)
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break;
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p = r->prog;
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proginfo(&info, p);
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if(info.flags & Call)
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return 0;
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if(info.reguse | info.regset)
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return 0;
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if((info.flags & Move) && (info.flags & (SizeL|SizeQ|SizeF|SizeD)) && p->to.type == v1->type)
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goto gotit;
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if(copyau(&p->from, v2) || copyau(&p->to, v2))
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break;
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if(copysub(&p->from, v1, v2, 0) || copysub(&p->to, v1, v2, 0))
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break;
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}
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return 0;
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gotit:
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copysub(&p->to, v1, v2, 1);
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if(debug['P']) {
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print("gotit: %D->%D\n%P", v1, v2, r->prog);
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if(p->from.type == v2->type)
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print(" excise");
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print("\n");
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}
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for(r=uniqs(r); r!=r0; r=uniqs(r)) {
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p = r->prog;
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copysub(&p->from, v1, v2, 1);
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copysub(&p->to, v1, v2, 1);
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if(debug['P'])
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print("%P\n", r->prog);
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}
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t = v1->type;
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v1->type = v2->type;
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v2->type = t;
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if(debug['P'])
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print("%P last\n", r->prog);
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return 1;
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}
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/*
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* The idea is to remove redundant copies.
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* v1->v2 F=0
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* (use v2 s/v2/v1/)*
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* set v1 F=1
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* use v2 return fail
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* -----------------
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* v1->v2 F=0
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* (use v2 s/v2/v1/)*
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* set v1 F=1
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* set v2 return success
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*/
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static int
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copyprop(Graph *g, Flow *r0)
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{
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Prog *p;
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Adr *v1, *v2;
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USED(g);
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p = r0->prog;
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v1 = &p->from;
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v2 = &p->to;
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if(copyas(v1, v2))
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return 1;
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gactive++;
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return copy1(v1, v2, r0->s1, 0);
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}
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static int
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copy1(Adr *v1, Adr *v2, Flow *r, int f)
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{
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int t;
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Prog *p;
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if(r->active == gactive) {
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if(debug['P'])
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print("act set; return 1\n");
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return 1;
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}
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r->active = gactive;
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if(debug['P'])
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print("copy %D->%D f=%d\n", v1, v2, f);
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for(; r != nil; r = r->s1) {
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p = r->prog;
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if(debug['P'])
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print("%P", p);
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if(!f && uniqp(r) == nil) {
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f = 1;
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if(debug['P'])
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print("; merge; f=%d", f);
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}
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t = copyu(p, v2, A);
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switch(t) {
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case 2: /* rar, can't split */
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if(debug['P'])
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print("; %D rar; return 0\n", v2);
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return 0;
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case 3: /* set */
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if(debug['P'])
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print("; %D set; return 1\n", v2);
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return 1;
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|
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case 1: /* used, substitute */
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case 4: /* use and set */
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if(f) {
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if(!debug['P'])
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return 0;
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if(t == 4)
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print("; %D used+set and f=%d; return 0\n", v2, f);
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else
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print("; %D used and f=%d; return 0\n", v2, f);
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return 0;
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}
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if(copyu(p, v2, v1)) {
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if(debug['P'])
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print("; sub fail; return 0\n");
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return 0;
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}
|
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if(debug['P'])
|
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print("; sub %D/%D", v2, v1);
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if(t == 4) {
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if(debug['P'])
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print("; %D used+set; return 1\n", v2);
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return 1;
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|
}
|
|
break;
|
|
}
|
|
if(!f) {
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t = copyu(p, v1, A);
|
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if(!f && (t == 2 || t == 3 || t == 4)) {
|
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f = 1;
|
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if(debug['P'])
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print("; %D set and !f; f=%d", v1, f);
|
|
}
|
|
}
|
|
if(debug['P'])
|
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print("\n");
|
|
if(r->s2)
|
|
if(!copy1(v1, v2, r->s2, f))
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return 0;
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|
}
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* return
|
|
* 1 if v only used (and substitute),
|
|
* 2 if read-alter-rewrite
|
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* 3 if set
|
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* 4 if set and used
|
|
* 0 otherwise (not touched)
|
|
*/
|
|
int
|
|
copyu(Prog *p, Adr *v, Adr *s)
|
|
{
|
|
ProgInfo info;
|
|
|
|
switch(p->as) {
|
|
case AJMP:
|
|
if(s != A) {
|
|
if(copysub(&p->to, v, s, 1))
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|
return 1;
|
|
return 0;
|
|
}
|
|
if(copyau(&p->to, v))
|
|
return 1;
|
|
return 0;
|
|
|
|
case ARET:
|
|
if(s != A)
|
|
return 1;
|
|
return 3;
|
|
|
|
case ACALL:
|
|
if(REGEXT && v->type <= REGEXT && v->type > exregoffset)
|
|
return 2;
|
|
if(REGARG >= 0 && v->type == (uchar)REGARG)
|
|
return 2;
|
|
if(v->type == p->from.type)
|
|
return 2;
|
|
|
|
if(s != A) {
|
|
if(copysub(&p->to, v, s, 1))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
if(copyau(&p->to, v))
|
|
return 4;
|
|
return 3;
|
|
|
|
case ATEXT:
|
|
if(REGARG >= 0 && v->type == (uchar)REGARG)
|
|
return 3;
|
|
return 0;
|
|
}
|
|
|
|
proginfo(&info, p);
|
|
|
|
if((info.reguse|info.regset) & RtoB(v->type))
|
|
return 2;
|
|
|
|
if(info.flags & LeftAddr)
|
|
if(copyas(&p->from, v))
|
|
return 2;
|
|
|
|
if((info.flags & (RightRead|RightWrite)) == (RightRead|RightWrite))
|
|
if(copyas(&p->to, v))
|
|
return 2;
|
|
|
|
if(info.flags & RightWrite) {
|
|
if(copyas(&p->to, v)) {
|
|
if(s != A)
|
|
return copysub(&p->from, v, s, 1);
|
|
if(copyau(&p->from, v))
|
|
return 4;
|
|
return 3;
|
|
}
|
|
}
|
|
|
|
if(info.flags & (LeftAddr|LeftRead|LeftWrite|RightAddr|RightRead|RightWrite)) {
|
|
if(s != A) {
|
|
if(copysub(&p->from, v, s, 1))
|
|
return 1;
|
|
return copysub(&p->to, v, s, 1);
|
|
}
|
|
if(copyau(&p->from, v))
|
|
return 1;
|
|
if(copyau(&p->to, v))
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* direct reference,
|
|
* could be set/use depending on
|
|
* semantics
|
|
*/
|
|
static int
|
|
copyas(Adr *a, Adr *v)
|
|
{
|
|
if(a->type != v->type)
|
|
return 0;
|
|
if(regtyp(v))
|
|
return 1;
|
|
if(v->type == D_AUTO || v->type == D_PARAM)
|
|
if(v->offset == a->offset)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* either direct or indirect
|
|
*/
|
|
static int
|
|
copyau(Adr *a, Adr *v)
|
|
{
|
|
|
|
if(copyas(a, v))
|
|
return 1;
|
|
if(regtyp(v)) {
|
|
if(a->type-D_INDIR == v->type)
|
|
return 1;
|
|
if(a->index == v->type)
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* substitute s for v in a
|
|
* return failure to substitute
|
|
*/
|
|
static int
|
|
copysub(Adr *a, Adr *v, Adr *s, int f)
|
|
{
|
|
int t;
|
|
|
|
if(copyas(a, v)) {
|
|
t = s->type;
|
|
if(t >= D_AX && t <= D_DI || t >= D_X0 && t <= D_X7) {
|
|
if(f)
|
|
a->type = t;
|
|
}
|
|
return 0;
|
|
}
|
|
if(regtyp(v)) {
|
|
t = v->type;
|
|
if(a->type == t+D_INDIR) {
|
|
if((s->type == D_BP) && a->index != D_NONE)
|
|
return 1; /* can't use BP-base with index */
|
|
if(f)
|
|
a->type = s->type+D_INDIR;
|
|
// return 0;
|
|
}
|
|
if(a->index == t) {
|
|
if(f)
|
|
a->index = s->type;
|
|
return 0;
|
|
}
|
|
return 0;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void
|
|
conprop(Flow *r0)
|
|
{
|
|
Flow *r;
|
|
Prog *p, *p0;
|
|
int t;
|
|
Adr *v0;
|
|
|
|
p0 = r0->prog;
|
|
v0 = &p0->to;
|
|
r = r0;
|
|
|
|
loop:
|
|
r = uniqs(r);
|
|
if(r == nil || r == r0)
|
|
return;
|
|
if(uniqp(r) == nil)
|
|
return;
|
|
|
|
p = r->prog;
|
|
t = copyu(p, v0, A);
|
|
switch(t) {
|
|
case 0: // miss
|
|
case 1: // use
|
|
goto loop;
|
|
|
|
case 2: // rar
|
|
case 4: // use and set
|
|
break;
|
|
|
|
case 3: // set
|
|
if(p->as == p0->as)
|
|
if(p->from.type == p0->from.type)
|
|
if(p->from.node == p0->from.node)
|
|
if(p->from.offset == p0->from.offset)
|
|
if(p->from.scale == p0->from.scale)
|
|
if(p->from.u.vval == p0->from.u.vval)
|
|
if(p->from.index == p0->from.index) {
|
|
excise(r);
|
|
goto loop;
|
|
}
|
|
break;
|
|
}
|
|
}
|