MWCC/compiler_and_linker/unsorted/StrengthReduction.c

752 lines
24 KiB
C

#include "compiler/StrengthReduction.h"
#include "compiler/BitVectors.h"
#include "compiler/CompilerTools.h"
#include "compiler/LoopDetection.h"
#include "compiler/PCode.h"
#include "compiler/PCodeInfo.h"
#include "compiler/Registers.h"
#include "compiler/UseDefChains.h"
int strengthreducedloops;
static PCode *findinitializer(Loop *loop, short reg) {
UInt32 *vec;
PCode *best;
RegUseOrDef *list;
vec = usedefinfo[loop->body->blockIndex].defvec8;
best = NULL;
for (list = reg_Defs[RegClass_GPR][reg]; list; list = list->next) {
if (
!(bitvectorgetbit(Defs[list->id].pcode->block->blockIndex, loop->memberblocks)) &&
bitvectorgetbit(list->id, vec)
)
{
if (best)
return NULL;
best = Defs[list->id].pcode;
}
}
if (best) {
if (best->op == PC_LI || best->op == PC_ADDI || best->op == PC_ADD)
return best;
}
return NULL;
}
static int isbasicinductionvariable(Loop *loop, short reg, SInt32 step) {
RegUseOrDef *list;
PCode *instr;
for (list = reg_Defs[RegClass_GPR][reg]; list; list = list->next) {
instr = Defs[list->id].pcode;
if (bitvectorgetbit(instr->block->blockIndex, loop->memberblocks)) {
if (instr->op != PC_ADDI)
return 0;
if (instr->args[1].data.reg.reg != reg)
return 0;
if (instr->args[2].data.imm.value != step)
return 0;
}
}
return 1;
}
static void addbasicinductionvariable(Loop *loop, short reg, SInt32 step) {
BasicInductionVar *biv;
RegUseOrDef *list;
PCode *instr;
InstrList *instrList;
for (biv = loop->basicInductionVars; biv; biv = biv->next) {
if (biv->reg == reg)
return;
}
biv = oalloc(sizeof(BasicInductionVar));
biv->next = loop->basicInductionVars;
loop->basicInductionVars = biv;
biv->loop = loop;
biv->inductionVars = NULL;
biv->instrsC = NULL;
biv->step = step;
biv->reg = reg;
for (list = reg_Defs[RegClass_GPR][reg]; list; list = list->next) {
instr = Defs[list->id].pcode;
if (bitvectorgetbit(instr->block->blockIndex, loop->memberblocks)) {
instrList = oalloc(sizeof(InstrList));
instrList->next = biv->instrsC;
biv->instrsC = instrList;
instrList->instr = instr;
}
}
biv->initializer = findinitializer(loop, reg);
}
static void findbasicinductionvariables(Loop *loop) {
SInt16 step;
BlockList *block;
PCode *instr;
short reg;
for (block = loop->blocks; block; block = block->next) {
for (instr = block->block->firstPCode; instr; instr = instr->nextPCode) {
if (instr->op == PC_ADDI) {
if (
(reg = instr->args[0].data.reg.reg) >= 32 &&
instr->args[1].data.reg.reg == reg &&
isbasicinductionvariable(loop, reg, step = instr->args[2].data.imm.value)
)
addbasicinductionvariable(loop, reg, step);
}
}
}
}
static void findallbasicinductionvariables(Loop *loop) {
while (loop) {
if (loop->children)
findallbasicinductionvariables(loop->children);
findbasicinductionvariables(loop);
loop = loop->nextSibling;
}
}
static int isinductionvariable(BasicInductionVar *biv, int useID, SInt32 *result1, short *result2, short *result3, Loop **result4) {
RegUseOrDef *list;
int counter;
Loop *loop;
Loop *scanloop;
PCode *instr;
instr = Uses[useID].pcode;
*result2 = 0;
*result3 = 0;
*result4 = NULL;
switch (instr->op) {
case PC_MULLI:
*result1 = instr->args[2].data.imm.value;
break;
case PC_RLWINM:
if (instr->args[3].data.imm.value)
return 0;
if (instr->args[2].data.imm.value > 15)
return 0;
if (instr->args[4].data.imm.value != (31 - instr->args[2].data.imm.value))
return 0;
if (PCODE_FLAG_SET_F(instr) & fRecordBit)
return 0;
*result1 = 1 << instr->args[2].data.imm.value;
break;
case PC_LBZX:
case PC_LHZX:
case PC_LHAX:
case PC_LWZX:
case PC_STBX:
case PC_STHX:
case PC_STWX:
case PC_LFSX:
case PC_LFDX:
case PC_STFSX:
case PC_STFDX:
*result2 = 0;
*result3 = 0;
if (instr->args[1].data.reg.reg == biv->reg) {
*result2 = 1;
*result3 = 2;
} else if (instr->args[2].data.reg.reg == biv->reg) {
*result2 = 2;
*result3 = 1;
}
counter = 0;
for (list = reg_Defs[RegClass_GPR][instr->args[*result3].data.reg.reg]; list; list = list->next) {
if (bitvectorgetbit(Defs[list->id].pcode->block->blockIndex, biv->loop->memberblocks))
counter++;
}
if (counter)
return 0;
loop = biv->loop;
for (scanloop = loop->parent; scanloop; scanloop = scanloop->parent) {
counter = 0;
for (list = reg_Defs[RegClass_GPR][instr->args[*result3].data.reg.reg]; list; list = list->next) {
if (bitvectorgetbit(Defs[list->id].pcode->block->blockIndex, scanloop->memberblocks))
counter++;
}
if (!biv->initializer || bitvectorgetbit(biv->initializer->block->blockIndex, scanloop->memberblocks))
counter++;
if (counter)
break;
loop = scanloop;
}
*result4 = loop;
*result1 = 1;
return 1;
default:
return 0;
}
counter = 0;
for (list = reg_Defs[RegClass_GPR][instr->args[0].data.reg.reg]; list; list = list->next) {
if (bitvectorgetbit(Defs[list->id].pcode->block->blockIndex, biv->loop->memberblocks))
counter++;
}
return counter == 1;
}
static void addinductionvariable(BasicInductionVar *biv, PCode *instr, SInt32 val1, short val2, short val3, Loop *val4) {
InductionVar *iv;
iv = oalloc(sizeof(InductionVar));
iv->next = biv->inductionVars;
biv->inductionVars = iv;
iv->basicVar = biv;
iv->instr = instr;
iv->instrC = NULL;
iv->step = val1;
iv->x18 = val2;
iv->x1A = val3;
iv->someloop = val4;
if (instr->flags & (fIsRead | fIsWrite))
iv->x1C = -1;
else
iv->x1C = instr->args[0].data.reg.reg;
iv->x1E = -1;
}
static void findnonbasicinductionvariables(Loop *loop) {
BasicInductionVar *biv;
RegUseOrDef *list;
SInt32 result1;
short result2;
short result3;
Loop *result4;
for (biv = loop->basicInductionVars; biv; biv = biv->next) {
for (list = reg_Uses[RegClass_GPR][biv->reg]; list; list = list->next) {
if (bitvectorgetbit(Uses[list->id].pcode->block->blockIndex, loop->memberblocks)) {
if (isinductionvariable(biv, list->id, &result1, &result2, &result3, &result4))
addinductionvariable(biv, Uses[list->id].pcode, result1, result2, result3, result4);
}
}
}
}
static void findallnonbasicinductionvariables(Loop *loop) {
while (loop) {
if (loop->children)
findallnonbasicinductionvariables(loop->children);
if (loop->basicInductionVars)
findnonbasicinductionvariables(loop);
loop = loop->nextSibling;
}
}
static void initializeinductionvariable(InductionVar *iv) {
BasicInductionVar *biv; // r31
PCode *instr; // r27
PCodeBlock *preheader; // r30
SInt32 value30; // r30
short reg29; // r29
short reg26; // r26
biv = iv->basicVar;
preheader = biv->loop->preheader;
if (iv->x1A) {
reg29 = iv->instr->args[iv->x1A].data.reg.reg;
reg26 = iv->instr->args[iv->x18].data.reg.reg;
instr = NULL;
if (
biv->initializer &&
biv->initializer->op == PC_LI &&
biv->initializer->block == preheader
)
{
if (biv->initializer->args[1].data.imm.value == 0)
instr = makepcode(PC_MR, iv->x1E, reg29);
else if (FITS_IN_SHORT(biv->initializer->args[1].data.imm.value))
instr = makepcode(PC_ADDI, iv->x1E, reg29, 0, biv->initializer->args[1].data.imm.value);
}
if (!instr)
instr = makepcode(PC_ADD, iv->x1E, reg29, reg26);
if (biv->initializer && instr->op != PC_ADD)
insertpcodeafter(biv->initializer, instr);
else if (iv->someloop && iv->someloop->preheader->lastPCode)
insertpcodebefore(iv->someloop->preheader->lastPCode, instr);
else
insertpcodebefore(preheader->lastPCode, instr);
iv->instrC = instr;
iv->x1C = reg29;
return;
}
if (!biv->initializer || biv->initializer->op != PC_LI) {
instr = copypcode(iv->instr);
instr->args[0].data.reg.reg = iv->x1E;
insertpcodebefore(preheader->lastPCode, instr);
} else {
value30 = biv->initializer->args[1].data.imm.value * iv->step;
if (!FITS_IN_SHORT(value30)) {
instr = makepcode(PC_LIS, iv->x1E, 0, HIGH_PART(value30));
insertpcodeafter(biv->initializer, instr);
if (value30 != 0)
insertpcodeafter(instr, makepcode(PC_ADDI, iv->x1E, iv->x1E, 0, LOW_PART(value30)));
} else {
instr = makepcode(PC_LI, iv->x1E, value30);
insertpcodeafter(biv->initializer, instr);
}
}
}
static void incrementinductionvariable(InductionVar *iv) {
SInt32 value;
BasicInductionVar *biv;
PCode *instr;
InstrList *list;
biv = iv->basicVar;
value = iv->step * biv->step;
for (list = biv->instrsC; list; list = list->next) {
if (!FITS_IN_SHORT(value)) {
instr = makepcode(PC_ADDIS, iv->x1E, iv->x1E, 0, HIGH_PART(value));
insertpcodeafter(list->instr, instr);
if (value != 0) {
instr = makepcode(PC_ADDI, iv->x1E, iv->x1E, 0, LOW_PART(value));
insertpcodeafter(list->instr->nextPCode, instr);
}
} else {
instr = makepcode(PC_ADDI, iv->x1E, iv->x1E, 0, value);
insertpcodeafter(list->instr, instr);
}
}
}
static void copyinductionvariable(InductionVar *iv) {
if (iv->instr->flags & (fIsRead | fIsWrite)) {
iv->instr->op -= 2;
iv->instr->args[1].data.reg.reg = iv->x1E;
iv->instr->args[2].kind = PCOp_IMMEDIATE;
iv->instr->args[2].data.imm.value = 0;
iv->instr->args[2].data.imm.obj = NULL;
} else {
insertpcodeafter(iv->instr, makepcode(PC_MR, iv->x1C, iv->x1E));
deletepcode(iv->instr);
}
}
static int testnestediv(InductionVar *iv, SInt32 step1, int reg, SInt32 step2, Loop *loop1, Loop *loop2) {
SInt32 addend;
BlockList *list;
PCode *instr;
PCodeArg *op;
int i;
if (iv->instrC && iv->x1C == reg) {
if (iv->instrC->op == PC_MR)
addend = 0;
else if (iv->instrC->op == PC_ADDI)
addend = iv->instrC->args[2].data.imm.value;
else
return 0;
if (step2 == (addend + (step1 * iv->step * loop2->iterationCount))) {
for (list = loop1->blocks; list && list->block != loop2->blocks->block; list = list->next) {
for (instr = list->block->firstPCode; instr; instr = instr->nextPCode) {
op = instr->args;
i = instr->argCount;
while (i--) {
if (
op->kind == PCOp_REGISTER &&
op->arg == RegClass_GPR &&
op->data.reg.reg == reg
)
return 0;
op++;
}
}
}
return 1;
}
}
return 0;
}
static void strengthreducenestediv(short reg, SInt32 step, PCode *initializer, Loop *loop) {
Loop *scanloop;
BasicInductionVar *biv;
InductionVar *iv;
PCode *instr;
PCodeArg *op;
int i;
for (scanloop = loop->children; scanloop; scanloop = scanloop->nextSibling) {
if (
scanloop->isKnownCountingLoop &&
scanloop->x4F &&
bitvectorgetbit(scanloop->body->blockIndex, loop->vec2C)
)
{
for (biv = scanloop->basicInductionVars; biv; biv = biv->next) {
for (iv = biv->inductionVars; iv; iv = iv->next) {
if (testnestediv(iv, biv->step, reg, step, loop, scanloop)) {
deletepcode(iv->instrC);
if (initializer) {
insertpcodeafter(initializer, iv->instrC);
} else if (loop->body->lastPCode) {
for (instr = loop->body->lastPCode; instr; instr = instr->prevPCode) {
op = instr->args;
i = instr->argCount;
while (i--) {
if (
op->kind == PCOp_REGISTER &&
op->arg == RegClass_GPR &&
(op->data.reg.effect & EffectWrite) &&
op->data.reg.reg == reg
)
break;
op++;
}
}
if (instr)
insertpcodeafter(instr, iv->instrC);
else
insertpcodebefore(loop->body->firstPCode, iv->instrC);
} else {
appendpcode(loop->body, iv->instrC);
}
}
}
}
}
}
}
static void strengthreducenestedbiv(BasicInductionVar *biv) {
Loop *loop;
InductionVar *iv;
loop = biv->loop;
for (iv = biv->inductionVars; iv; iv = iv->next)
strengthreducenestediv(iv->x1E, iv->step * biv->step, iv->instrC, loop);
strengthreducenestediv(biv->reg, biv->step, biv->initializer, loop);
}
static void strengthreduceinductionvariable(BasicInductionVar *biv) {
int counter;
InductionVar *iv;
InductionVar *otherIv;
short reg;
counter = 0;
for (iv = biv->inductionVars; iv; iv = iv->next) {
if (iv->step == 1)
counter++;
}
for (iv = biv->inductionVars; iv; iv = iv->next) {
if (
(counter <= 4 || iv->step != 1) &&
iv->instr->block &&
(iv->x1A == 0 || iv->instr->args[2].kind != PCOp_IMMEDIATE)
)
{
if (iv->x1E == -1) {
iv->x1E = used_virtual_registers[RegClass_GPR]++;
initializeinductionvariable(iv);
incrementinductionvariable(iv);
if (iv->step == 1) {
reg = iv->instr->args[iv->x1A].data.reg.reg;
for (otherIv = iv->next; otherIv; otherIv = otherIv->next) {
if (otherIv->x1A != 0 && otherIv->instr->args[otherIv->x1A].data.reg.reg == reg)
otherIv->x1E = iv->x1E;
}
} else {
for (otherIv = iv->next; otherIv; otherIv = otherIv->next) {
if (otherIv->step == iv->step)
otherIv->x1E = iv->x1E;
}
}
}
copyinductionvariable(iv);
strengthreducedloops = 1;
}
}
}
#ifdef __MWERKS__
#pragma options align=mac68k
#endif
typedef struct BivInit {
SInt32 x0;
short x4;
short x6;
short x8;
Object *xA;
} BivInit;
#ifdef __MWERKS__
#pragma options align=reset
#endif
static void calc_biv_init(BasicInductionVar *biv, BivInit *init) {
PCode *instr;
PCode *scan;
PCodeArg *op;
int i;
instr = biv->initializer;
init->x0 = 0;
init->x4 = -1;
init->x6 = -1;
init->x8 = 0;
init->xA = NULL;
if (!biv->initializer || (biv->initializer->op != PC_ADDI && biv->initializer->op != PC_ADD))
return;
if (instr->op == PC_ADDI) {
if (instr->args[1].data.reg.reg == biv->reg) {
init->x0 = instr->args[2].data.imm.value;
for (scan = instr->prevPCode; scan; scan = scan->prevPCode) {
op = scan->args;
i = scan->argCount;
while (i--) {
if (
op->kind == PCOp_REGISTER &&
op->arg == RegClass_GPR &&
op->data.reg.reg == biv->reg &&
(op->data.reg.effect & EffectWrite)
)
{
if (scan->op == PC_ADD) {
init->x4 = scan->args[1].data.reg.reg;
init->x6 = scan->args[2].data.reg.reg;
} else if (scan->op == PC_ADDI) {
if (scan->args[2].kind == PCOp_IMMEDIATE) {
init->x4 = scan->args[1].data.reg.reg;
init->x8 = scan->args[2].data.imm.value;
} else if (scan->args[2].kind == PCOp_MEMORY) {
init->x4 = scan->args[1].data.reg.reg;
init->x8 = scan->args[2].data.mem.offset;
init->xA = scan->args[2].data.mem.obj;
}
}
return;
}
op++;
}
}
} else {
if (instr->args[2].kind == PCOp_IMMEDIATE) {
init->x4 = instr->args[1].data.reg.reg;
init->x8 = instr->args[2].data.imm.value;
} else if (instr->args[2].kind == PCOp_MEMORY) {
init->x4 = instr->args[1].data.reg.reg;
init->x8 = instr->args[2].data.mem.offset;
init->xA = instr->args[2].data.mem.obj;
}
}
} else if (instr->op == PC_ADD) {
if (instr->args[1].data.reg.reg == biv->reg) {
init->x6 = instr->args[2].data.reg.reg;
for (scan = instr->prevPCode; scan; scan = scan->prevPCode) {
op = scan->args;
i = scan->argCount;
while (i--) {
if (
op->kind == PCOp_REGISTER &&
op->arg == RegClass_GPR &&
op->data.reg.reg == biv->reg &&
(op->data.reg.effect & EffectWrite) &&
scan->op == PC_ADDI
)
{
if (scan->args[2].kind == PCOp_IMMEDIATE) {
init->x4 = scan->args[1].data.reg.reg;
init->x8 = scan->args[2].data.imm.value;
} else if (scan->args[2].kind == PCOp_MEMORY) {
init->x4 = scan->args[1].data.reg.reg;
init->x8 = scan->args[2].data.mem.offset;
init->xA = scan->args[2].data.mem.obj;
}
return;
}
op++;
}
}
} else {
init->x4 = instr->args[1].data.reg.reg;
init->x6 = instr->args[2].data.reg.reg;
}
}
}
static void combineinductionvariables(Loop *loop, BasicInductionVar *biv1, BasicInductionVar *biv2, SInt32 difference) {
PCode *instr1; // r31
int reg1; // r30
int reg2; // r29
PCode *instr2; // r24
PCodeBlock *nextBlock; // r24
BlockList *list;
PCodeArg *op;
int i;
PCode *instr;
instr1 = NULL;
instr2 = NULL;
reg1 = biv1->reg;
CError_ASSERT(930, reg1 >= 0);
reg2 = biv2->reg;
CError_ASSERT(934, reg2 >= 0);
if (!FITS_IN_SHORT(difference))
return;
for (list = loop->blocks; list; list = list->next) {
for (instr = list->block->firstPCode; instr; instr = instr->nextPCode) {
if (instr1) {
op = instr->args;
i = instr->argCount;
while (i--) {
if (
op->kind == PCOp_REGISTER &&
op->arg == RegClass_GPR &&
op->data.reg.reg == reg1
)
return;
op++;
}
}
if (instr->op == PC_ADDI) {
if (instr->args[0].data.reg.reg == reg1) {
if (instr1)
return;
instr1 = instr;
} else if (instr->args[0].data.reg.reg == reg2) {
if (instr2)
return;
instr2 = instr;
}
}
}
}
if (loop->body->lastPCode->flags & fIsBranch) {
nextBlock = NULL;
for (i = 0; i < loop->body->lastPCode->argCount; i++) {
if (loop->body->lastPCode->args[i].kind == PCOp_LABEL) {
nextBlock = loop->body->lastPCode->args[i].data.label.label->block;
break;
}
}
if (!nextBlock)
return;
} else {
nextBlock = loop->body->nextBlock;
}
deletepcode(instr1);
instr1->args[1].data.reg.reg = reg2;
instr1->args[2].data.imm.value = difference;
if (nextBlock->firstPCode)
insertpcodebefore(nextBlock->firstPCode, instr1);
else
appendpcode(nextBlock, instr1);
biv1->reg = -1;
strengthreducedloops = 1;
}
static void strengthreduceinductionvariables(Loop *loop) {
BasicInductionVar *biv1;
BasicInductionVar *biv2;
BivInit init1;
BivInit init2;
for (biv1 = loop->basicInductionVars; biv1; biv1 = biv1->next) {
if (biv1->inductionVars)
strengthreduceinductionvariable(biv1);
strengthreducenestedbiv(biv1);
}
for (biv1 = loop->basicInductionVars; biv1; biv1 = biv1->next) {
if (biv1->reg != -1) {
calc_biv_init(biv1, &init1);
if (init1.x4 != -1) {
for (biv2 = loop->basicInductionVars; biv2; biv2 = biv2->next) {
if (biv2->reg != -1 && biv2 != biv1) {
calc_biv_init(biv2, &init2);
if (
init2.x4 != -1 &&
init1.x4 == init2.x4 &&
init1.x6 == init2.x6 &&
init1.x8 == init2.x8 &&
init1.xA == init2.xA &&
biv1->step == biv2->step
)
{
if (init1.x0 < init2.x0) {
combineinductionvariables(loop, biv2, biv1, init2.x0 - init1.x0);
} else {
combineinductionvariables(loop, biv1, biv2, init1.x0 - init2.x0);
break;
}
}
}
}
}
}
}
}
static void strengthreduceallinductionvariables(Loop *loop) {
while (loop) {
if (loop->children)
strengthreduceallinductionvariables(loop->children);
if (loop->basicInductionVars)
strengthreduceinductionvariables(loop);
loop = loop->nextSibling;
}
}
void strengthreduceloops(void) {
strengthreducedloops = 0;
if (loopsinflowgraph) {
computeusedefchains(0);
findallbasicinductionvariables(loopsinflowgraph);
findallnonbasicinductionvariables(loopsinflowgraph);
strengthreduceallinductionvariables(loopsinflowgraph);
freeoheap();
}
}