//Check and replace 'exp' with 'cand_expr' if they are
//equal, and update SSA info. If 'cand_expr' is NOT leaf,
//that will create redundant computation, and
//depends on later Redundancy Elimination to reverse back.
//
//'cand_expr': substitute cand_expr for exp.
// e.g: exp is pr1 of S2, cand_expr is 10.
// pr1 = 10 //S1
// g = pr1 //S2
// =>
// pr1 = 10
// g = 10
//
//NOTE: Do NOT handle stmt.
void IR_CP::replaceExpViaSSADu(IR * exp, IR const* cand_expr,
IN OUT CPCtx & ctx)
{
ASSERT0(exp && exp->is_exp() && cand_expr && cand_expr->is_exp());
ASSERT0(exp->get_exact_ref());
if (!checkTypeConsistency(exp, cand_expr)) {
return;
}
IR * parent = IR_parent(exp);
if (parent->is_ild()) {
CPC_need_recomp_aa(ctx) = true;
} else if (parent->is_ist() && exp == IST_base(parent)) {
if (!cand_expr->is_ld() &&
!cand_expr->is_pr() &&
!cand_expr->is_lda()) {
return;
}
CPC_need_recomp_aa(ctx) = true;
}
IR * newir = m_ru->dupIRTree(cand_expr);
if (cand_expr->is_read_pr() && PR_ssainfo(cand_expr) != NULL) {
PR_ssainfo(newir) = PR_ssainfo(cand_expr);
SSA_uses(PR_ssainfo(newir)).append(newir);
} else {
m_du->copyIRTreeDU(newir, cand_expr, true);
}
//cand_expr may be IR tree. And there might be PR or LD on the tree.
newir->copyRefForTree(cand_expr, m_ru);
//Add SSA use for new exp.
SSAInfo * cand_ssainfo = NULL;
if ((cand_ssainfo = cand_expr->get_ssainfo()) != NULL) {
SSA_uses(cand_ssainfo).append(newir);
}
//Remove old exp SSA use.
SSAInfo * exp_ssainfo = exp->get_ssainfo();
ASSERT0(exp_ssainfo);
ASSERT0(SSA_uses(exp_ssainfo).find(exp));
SSA_uses(exp_ssainfo).remove(exp);
CPC_change(ctx) = true;
ASSERT0(exp->get_stmt());
bool doit = parent->replaceKid(exp, newir, false);
ASSERT0(doit);
UNUSED(doit);
m_ru->freeIRTree(exp);
}
//Duplicate and add an operand that indicated by opnd_pos at phi stmt
//in one of bb's successors.
void IRBB::dupSuccessorPhiOpnd(CFG<IRBB, IR> * cfg, Region * ru, UINT opnd_pos)
{
IR_CFG * ircfg = (IR_CFG*)cfg;
Vertex * vex = ircfg->get_vertex(BB_id(this));
ASSERT0(vex);
for (EdgeC * out = VERTEX_out_list(vex);
out != NULL; out = EC_next(out)) {
Vertex * succ_vex = EDGE_to(EC_edge(out));
IRBB * succ = ircfg->get_bb(VERTEX_id(succ_vex));
ASSERT0(succ);
for (IR * ir = BB_first_ir(succ);
ir != NULL; ir = BB_next_ir(succ)) {
if (!ir->is_phi()) {
break;
}
ASSERT0(cnt_list(PHI_opnd_list(ir)) >= opnd_pos);
IR * opnd;
UINT lpos = opnd_pos;
for (opnd = PHI_opnd_list(ir);
lpos != 0; opnd = opnd->get_next()) {
ASSERT0(opnd);
lpos--;
}
IR * newopnd = ru->dupIRTree(opnd);
if (opnd->is_read_pr()) {
newopnd->copyRef(opnd, ru);
ASSERT0(PR_ssainfo(opnd));
PR_ssainfo(newopnd) = PR_ssainfo(opnd);
SSA_uses(PR_ssainfo(newopnd)).append(newopnd);
}
((CPhi*)ir)->addOpnd(newopnd);
}
}
}
