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shader: Properly store phi on Inst

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This commit is contained in:
ReinUsesLisp 2021-02-06 02:38:22 -03:00 • committed by ameerj
parent 16cb00c521
commit da8096e6e3
6 changed files with 132 additions and 75 deletions
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22
src/shader_recompiler/ir_opt/ssa_rewrite_pass.cpp
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@ -104,32 +104,34 @@ private:
val = ReadVariable(variable, preds.front());
} else {
// Break potential cycles with operandless phi
val = IR::Value{&*block->PrependNewInst(block->begin(), IR::Opcode::Phi)};
IR::Inst& phi_inst{*block->PrependNewInst(block->begin(), IR::Opcode::Phi)};
val = IR::Value{&phi_inst};
WriteVariable(variable, block, val);
val = AddPhiOperands(variable, val, block);
val = AddPhiOperands(variable, phi_inst, block);
}
WriteVariable(variable, block, val);
return val;
}
IR::Value AddPhiOperands(auto variable, const IR::Value& phi, IR::Block* block) {
IR::Value AddPhiOperands(auto variable, IR::Inst& phi, IR::Block* block) {
for (IR::Block* const pred : block->ImmediatePredecessors()) {
phi.Inst()->AddPhiOperand(pred, ReadVariable(variable, pred));
phi.AddPhiOperand(pred, ReadVariable(variable, pred));
}
return TryRemoveTrivialPhi(phi, block, UndefOpcode(variable));
}
IR::Value TryRemoveTrivialPhi(const IR::Value& phi, IR::Block* block, IR::Opcode undef_opcode) {
IR::Value TryRemoveTrivialPhi(IR::Inst& phi, IR::Block* block, IR::Opcode undef_opcode) {
IR::Value same;
for (const auto& pair : phi.Inst()->PhiOperands()) {
const IR::Value& op{pair.second};
if (op == same || op == phi) {
const size_t num_args{phi.NumArgs()};
for (size_t arg_index = 0; arg_index < num_args; ++arg_index) {
const IR::Value& op{phi.Arg(arg_index)};
if (op == same || op == IR::Value{&phi}) {
// Unique value or self-reference
continue;
}
if (!same.IsEmpty()) {
// The phi merges at least two values: not trivial
return phi;
return IR::Value{&phi};
}
same = op;
}
@ -139,7 +141,7 @@ private:
same = IR::Value{&*block->PrependNewInst(first_not_phi, undef_opcode)};
}
// Reroute all uses of phi to same and remove phi
phi.Inst()->ReplaceUsesWith(same);
phi.ReplaceUsesWith(same);
// TODO: Try to recursively remove all phi users, which might have become trivial
return same;
}