0,0 → 1,552 |
/* |
* Copyright 2011 Christoph Bumiller |
* |
* Permission is hereby granted, free of charge, to any person obtaining a |
* copy of this software and associated documentation files (the "Software"), |
* to deal in the Software without restriction, including without limitation |
* the rights to use, copy, modify, merge, publish, distribute, sublicense, |
* and/or sell copies of the Software, and to permit persons to whom the |
* Software is furnished to do so, subject to the following conditions: |
* |
* The above copyright notice and this permission notice shall be included in |
* all copies or substantial portions of the Software. |
* |
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR |
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, |
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR |
* OTHER DEALINGS IN THE SOFTWARE. |
*/ |
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#include "codegen/nv50_ir.h" |
#include "codegen/nv50_ir_target.h" |
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namespace nv50_ir { |
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// Converts nv50 IR generated from TGSI to SSA form. |
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// DominatorTree implements an algorithm for finding immediate dominators, |
// as described by T. Lengauer & R. Tarjan. |
class DominatorTree : public Graph |
{ |
public: |
DominatorTree(Graph *cfg); |
~DominatorTree() { } |
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bool dominates(BasicBlock *, BasicBlock *); |
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void findDominanceFrontiers(); |
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private: |
void build(); |
void buildDFS(Node *); |
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void squash(int); |
inline void link(int, int); |
inline int eval(int); |
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void debugPrint(); |
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Graph *cfg; |
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Node **vert; |
int *data; |
const int count; |
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#define SEMI(i) (data[(i) + 0 * count]) |
#define ANCESTOR(i) (data[(i) + 1 * count]) |
#define PARENT(i) (data[(i) + 2 * count]) |
#define LABEL(i) (data[(i) + 3 * count]) |
#define DOM(i) (data[(i) + 4 * count]) |
}; |
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void DominatorTree::debugPrint() |
{ |
for (int i = 0; i < count; ++i) { |
INFO("SEMI(%i) = %i\n", i, SEMI(i)); |
INFO("ANCESTOR(%i) = %i\n", i, ANCESTOR(i)); |
INFO("PARENT(%i) = %i\n", i, PARENT(i)); |
INFO("LABEL(%i) = %i\n", i, LABEL(i)); |
INFO("DOM(%i) = %i\n", i, DOM(i)); |
} |
} |
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DominatorTree::DominatorTree(Graph *cfgraph) : cfg(cfgraph), |
count(cfg->getSize()) |
{ |
int i = 0; |
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vert = new Node * [count]; |
data = new int[5 * count]; |
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for (IteratorRef it = cfg->iteratorDFS(true); !it->end(); it->next(), ++i) { |
vert[i] = reinterpret_cast<Node *>(it->get()); |
vert[i]->tag = i; |
LABEL(i) = i; |
SEMI(i) = ANCESTOR(i) = -1; |
} |
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build(); |
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delete[] vert; |
delete[] data; |
} |
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void DominatorTree::buildDFS(Graph::Node *node) |
{ |
SEMI(node->tag) = node->tag; |
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for (Graph::EdgeIterator ei = node->outgoing(); !ei.end(); ei.next()) { |
if (SEMI(ei.getNode()->tag) < 0) { |
buildDFS(ei.getNode()); |
PARENT(ei.getNode()->tag) = node->tag; |
} |
} |
} |
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void DominatorTree::squash(int v) |
{ |
if (ANCESTOR(ANCESTOR(v)) >= 0) { |
squash(ANCESTOR(v)); |
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if (SEMI(LABEL(ANCESTOR(v))) < SEMI(LABEL(v))) |
LABEL(v) = LABEL(ANCESTOR(v)); |
ANCESTOR(v) = ANCESTOR(ANCESTOR(v)); |
} |
} |
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int DominatorTree::eval(int v) |
{ |
if (ANCESTOR(v) < 0) |
return v; |
squash(v); |
return LABEL(v); |
} |
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void DominatorTree::link(int v, int w) |
{ |
ANCESTOR(w) = v; |
} |
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void DominatorTree::build() |
{ |
DLList *bucket = new DLList[count]; |
Node *nv, *nw; |
int p, u, v, w; |
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buildDFS(cfg->getRoot()); |
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for (w = count - 1; w >= 1; --w) { |
nw = vert[w]; |
assert(nw->tag == w); |
for (Graph::EdgeIterator ei = nw->incident(); !ei.end(); ei.next()) { |
nv = ei.getNode(); |
v = nv->tag; |
u = eval(v); |
if (SEMI(u) < SEMI(w)) |
SEMI(w) = SEMI(u); |
} |
p = PARENT(w); |
bucket[SEMI(w)].insert(nw); |
link(p, w); |
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for (DLList::Iterator it = bucket[p].iterator(); !it.end(); it.erase()) { |
v = reinterpret_cast<Node *>(it.get())->tag; |
u = eval(v); |
DOM(v) = (SEMI(u) < SEMI(v)) ? u : p; |
} |
} |
for (w = 1; w < count; ++w) { |
if (DOM(w) != SEMI(w)) |
DOM(w) = DOM(DOM(w)); |
} |
DOM(0) = 0; |
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insert(&BasicBlock::get(cfg->getRoot())->dom); |
do { |
p = 0; |
for (v = 1; v < count; ++v) { |
nw = &BasicBlock::get(vert[DOM(v)])->dom;; |
nv = &BasicBlock::get(vert[v])->dom; |
if (nw->getGraph() && !nv->getGraph()) { |
++p; |
nw->attach(nv, Graph::Edge::TREE); |
} |
} |
} while (p); |
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delete[] bucket; |
} |
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#undef SEMI |
#undef ANCESTOR |
#undef PARENT |
#undef LABEL |
#undef DOM |
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void DominatorTree::findDominanceFrontiers() |
{ |
BasicBlock *bb; |
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for (IteratorRef dtIt = iteratorDFS(false); !dtIt->end(); dtIt->next()) { |
EdgeIterator succIt, chldIt; |
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bb = BasicBlock::get(reinterpret_cast<Node *>(dtIt->get())); |
bb->getDF().clear(); |
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for (succIt = bb->cfg.outgoing(); !succIt.end(); succIt.next()) { |
BasicBlock *dfLocal = BasicBlock::get(succIt.getNode()); |
if (dfLocal->idom() != bb) |
bb->getDF().insert(dfLocal); |
} |
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for (chldIt = bb->dom.outgoing(); !chldIt.end(); chldIt.next()) { |
BasicBlock *cb = BasicBlock::get(chldIt.getNode()); |
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DLList::Iterator dfIt = cb->getDF().iterator(); |
for (; !dfIt.end(); dfIt.next()) { |
BasicBlock *dfUp = BasicBlock::get(dfIt); |
if (dfUp->idom() != bb) |
bb->getDF().insert(dfUp); |
} |
} |
} |
} |
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// liveIn(bb) = usedBeforeAssigned(bb) U (liveOut(bb) - assigned(bb)) |
void |
Function::buildLiveSetsPreSSA(BasicBlock *bb, const int seq) |
{ |
Function *f = bb->getFunction(); |
BitSet usedBeforeAssigned(allLValues.getSize(), true); |
BitSet assigned(allLValues.getSize(), true); |
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bb->liveSet.allocate(allLValues.getSize(), false); |
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int n = 0; |
for (Graph::EdgeIterator ei = bb->cfg.outgoing(); !ei.end(); ei.next()) { |
BasicBlock *out = BasicBlock::get(ei.getNode()); |
if (out == bb) |
continue; |
if (out->cfg.visit(seq)) |
buildLiveSetsPreSSA(out, seq); |
if (!n++) |
bb->liveSet = out->liveSet; |
else |
bb->liveSet |= out->liveSet; |
} |
if (!n && !bb->liveSet.marker) |
bb->liveSet.fill(0); |
bb->liveSet.marker = true; |
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for (Instruction *i = bb->getEntry(); i; i = i->next) { |
for (int s = 0; i->srcExists(s); ++s) |
if (i->getSrc(s)->asLValue() && !assigned.test(i->getSrc(s)->id)) |
usedBeforeAssigned.set(i->getSrc(s)->id); |
for (int d = 0; i->defExists(d); ++d) |
assigned.set(i->getDef(d)->id); |
} |
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if (bb == BasicBlock::get(f->cfgExit)) { |
for (std::deque<ValueRef>::iterator it = f->outs.begin(); |
it != f->outs.end(); ++it) { |
if (!assigned.test(it->get()->id)) |
usedBeforeAssigned.set(it->get()->id); |
} |
} |
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bb->liveSet.andNot(assigned); |
bb->liveSet |= usedBeforeAssigned; |
} |
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void |
Function::buildDefSetsPreSSA(BasicBlock *bb, const int seq) |
{ |
bb->defSet.allocate(allLValues.getSize(), !bb->liveSet.marker); |
bb->liveSet.marker = true; |
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for (Graph::EdgeIterator ei = bb->cfg.incident(); !ei.end(); ei.next()) { |
BasicBlock *in = BasicBlock::get(ei.getNode()); |
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if (in->cfg.visit(seq)) |
buildDefSetsPreSSA(in, seq); |
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bb->defSet |= in->defSet; |
} |
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for (Instruction *i = bb->getEntry(); i; i = i->next) { |
for (int d = 0; i->defExists(d); ++d) |
bb->defSet.set(i->getDef(d)->id); |
} |
} |
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class RenamePass |
{ |
public: |
RenamePass(Function *); |
~RenamePass(); |
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bool run(); |
void search(BasicBlock *); |
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inline LValue *getStackTop(Value *); |
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LValue *mkUndefined(Value *); |
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private: |
Stack *stack; |
Function *func; |
Program *prog; |
}; |
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bool |
Program::convertToSSA() |
{ |
for (ArrayList::Iterator fi = allFuncs.iterator(); !fi.end(); fi.next()) { |
Function *fn = reinterpret_cast<Function *>(fi.get()); |
if (!fn->convertToSSA()) |
return false; |
} |
return true; |
} |
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// XXX: add edge from entry to exit ? |
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// Efficiently Computing Static Single Assignment Form and |
// the Control Dependence Graph, |
// R. Cytron, J. Ferrante, B. K. Rosen, M. N. Wegman, F. K. Zadeck |
bool |
Function::convertToSSA() |
{ |
// 0. calculate live in variables (for pruned SSA) |
buildLiveSets(); |
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// 1. create the dominator tree |
domTree = new DominatorTree(&cfg); |
reinterpret_cast<DominatorTree *>(domTree)->findDominanceFrontiers(); |
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// 2. insert PHI functions |
DLList workList; |
LValue *lval; |
BasicBlock *bb; |
int var; |
int iterCount = 0; |
int *hasAlready = new int[allBBlocks.getSize() * 2]; |
int *work = &hasAlready[allBBlocks.getSize()]; |
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memset(hasAlready, 0, allBBlocks.getSize() * 2 * sizeof(int)); |
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// for each variable |
for (var = 0; var < allLValues.getSize(); ++var) { |
if (!allLValues.get(var)) |
continue; |
lval = reinterpret_cast<Value *>(allLValues.get(var))->asLValue(); |
if (!lval || lval->defs.empty()) |
continue; |
++iterCount; |
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// TODO: don't add phi functions for values that aren't used outside |
// the BB they're defined in |
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// gather blocks with assignments to lval in workList |
for (Value::DefIterator d = lval->defs.begin(); |
d != lval->defs.end(); ++d) { |
bb = ((*d)->getInsn() ? (*d)->getInsn()->bb : NULL); |
if (!bb) |
continue; // instruction likely been removed but not XXX deleted |
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if (work[bb->getId()] == iterCount) |
continue; |
work[bb->getId()] = iterCount; |
workList.insert(bb); |
} |
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// for each block in workList, insert a phi for lval in the block's |
// dominance frontier (if we haven't already done so) |
for (DLList::Iterator wI = workList.iterator(); !wI.end(); wI.erase()) { |
bb = BasicBlock::get(wI); |
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DLList::Iterator dfIter = bb->getDF().iterator(); |
for (; !dfIter.end(); dfIter.next()) { |
Instruction *phi; |
BasicBlock *dfBB = BasicBlock::get(dfIter); |
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if (hasAlready[dfBB->getId()] >= iterCount) |
continue; |
hasAlready[dfBB->getId()] = iterCount; |
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// pruned SSA: don't need a phi if the value is not live-in |
if (!dfBB->liveSet.test(lval->id)) |
continue; |
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phi = new_Instruction(this, OP_PHI, typeOfSize(lval->reg.size)); |
dfBB->insertTail(phi); |
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phi->setDef(0, lval); |
for (int s = 0; s < dfBB->cfg.incidentCount(); ++s) |
phi->setSrc(s, lval); |
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if (work[dfBB->getId()] < iterCount) { |
work[dfBB->getId()] = iterCount; |
wI.insert(dfBB); |
} |
} |
} |
} |
delete[] hasAlready; |
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RenamePass rename(this); |
return rename.run(); |
} |
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RenamePass::RenamePass(Function *fn) : func(fn), prog(fn->getProgram()) |
{ |
stack = new Stack[func->allLValues.getSize()]; |
} |
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RenamePass::~RenamePass() |
{ |
if (stack) |
delete[] stack; |
} |
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LValue * |
RenamePass::getStackTop(Value *val) |
{ |
if (!stack[val->id].getSize()) |
return 0; |
return reinterpret_cast<LValue *>(stack[val->id].peek().u.p); |
} |
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LValue * |
RenamePass::mkUndefined(Value *val) |
{ |
LValue *lval = val->asLValue(); |
assert(lval); |
LValue *ud = new_LValue(func, lval); |
Instruction *nop = new_Instruction(func, OP_NOP, typeOfSize(lval->reg.size)); |
nop->setDef(0, ud); |
BasicBlock::get(func->cfg.getRoot())->insertHead(nop); |
return ud; |
} |
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bool RenamePass::run() |
{ |
if (!stack) |
return false; |
search(BasicBlock::get(func->domTree->getRoot())); |
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return true; |
} |
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// Go through BBs in dominance order, create new values for each definition, |
// and replace all sources with their current new values. |
// |
// NOTE: The values generated for function inputs/outputs have no connection |
// to their corresponding outputs/inputs in other functions. Only allocation |
// of physical registers will establish this connection. |
// |
void RenamePass::search(BasicBlock *bb) |
{ |
LValue *lval, *ssa; |
int d, s; |
const Target *targ = prog->getTarget(); |
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// Put current definitions for function inputs values on the stack. |
// They can be used before any redefinitions are pushed. |
if (bb == BasicBlock::get(func->cfg.getRoot())) { |
for (std::deque<ValueDef>::iterator it = func->ins.begin(); |
it != func->ins.end(); ++it) { |
lval = it->get()->asLValue(); |
assert(lval); |
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ssa = new_LValue(func, targ->nativeFile(lval->reg.file)); |
ssa->reg.size = lval->reg.size; |
ssa->reg.data.id = lval->reg.data.id; |
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it->setSSA(ssa); |
stack[lval->id].push(ssa); |
} |
} |
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for (Instruction *stmt = bb->getFirst(); stmt; stmt = stmt->next) { |
// PHI sources get definitions from the passes through the incident BBs, |
// so skip them here. |
if (stmt->op != OP_PHI) { |
for (s = 0; stmt->srcExists(s); ++s) { |
lval = stmt->getSrc(s)->asLValue(); |
if (!lval) |
continue; |
// Values on the stack created in previously visited blocks, and |
// function inputs, will be valid because they dominate this one. |
lval = getStackTop(lval); |
if (!lval) |
lval = mkUndefined(stmt->getSrc(s)); |
stmt->setSrc(s, lval); |
} |
} |
for (d = 0; stmt->defExists(d); ++d) { |
lval = stmt->def(d).get()->asLValue(); |
assert(lval); |
stmt->def(d).setSSA( |
new_LValue(func, targ->nativeFile(lval->reg.file))); |
stmt->def(d).get()->reg.size = lval->reg.size; |
stmt->def(d).get()->reg.data.id = lval->reg.data.id; |
stack[lval->id].push(stmt->def(d).get()); |
} |
} |
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// Update sources of PHI ops corresponding to this BB in outgoing BBs. |
for (Graph::EdgeIterator ei = bb->cfg.outgoing(); !ei.end(); ei.next()) { |
Instruction *phi; |
int p = 0; |
BasicBlock *sb = BasicBlock::get(ei.getNode()); |
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// which predecessor of sb is bb ? |
for (Graph::EdgeIterator ei = sb->cfg.incident(); !ei.end(); ei.next()) { |
if (ei.getNode() == &bb->cfg) |
break; |
++p; |
} |
assert(p < sb->cfg.incidentCount()); |
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for (phi = sb->getPhi(); phi && phi->op == OP_PHI; phi = phi->next) { |
lval = getStackTop(phi->getSrc(p)); |
if (!lval) |
lval = mkUndefined(phi->getSrc(p)); |
phi->setSrc(p, lval); |
} |
} |
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// Visit the BBs we dominate. |
for (Graph::EdgeIterator ei = bb->dom.outgoing(); !ei.end(); ei.next()) |
search(BasicBlock::get(ei.getNode())); |
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// Update function outputs to the last definitions of their pre-SSA values. |
// I hope they're unique, i.e. that we get PHIs for all of them ... |
if (bb == BasicBlock::get(func->cfgExit)) { |
for (std::deque<ValueRef>::iterator it = func->outs.begin(); |
it != func->outs.end(); ++it) { |
lval = it->get()->asLValue(); |
if (!lval) |
continue; |
lval = getStackTop(lval); |
if (!lval) |
lval = mkUndefined(it->get()); |
it->set(lval); |
} |
} |
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// Pop the values we created in this block from the stack because we will |
// return to blocks that we do not dominate. |
for (Instruction *stmt = bb->getFirst(); stmt; stmt = stmt->next) { |
if (stmt->op == OP_NOP) |
continue; |
for (d = 0; stmt->defExists(d); ++d) |
stack[stmt->def(d).preSSA()->id].pop(); |
} |
} |
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} // namespace nv50_ir |