void ExprCompiler::visit(AssignExpr& expr, int dest)
{
// Compile the value and also make it the result of the expression.
compile(expr.value(), dest);
// Now assign it to the left-hand side.
expr.lvalue()->accept(*this, dest);
}
void Resolver::visit(AssignExpr& expr, int dummy)
{
resolve(expr.value());
expr.lvalue()->accept(*this, dummy);
}
/** Given an AST node, check to see if it's safe if we happen to run the
code for that node with the execution mask all off.
*/
static bool
lCheckAllOffSafety(ASTNode *node, void *data) {
bool *okPtr = (bool *)data;
FunctionCallExpr *fce;
if ((fce = llvm::dyn_cast<FunctionCallExpr>(node)) != NULL) {
if (fce->func == NULL)
return false;
const Type *type = fce->func->GetType();
const PointerType *pt = CastType<PointerType>(type);
if (pt != NULL)
type = pt->GetBaseType();
const FunctionType *ftype = CastType<FunctionType>(type);
Assert(ftype != NULL);
if (ftype->isSafe == false) {
*okPtr = false;
return false;
}
}
if (llvm::dyn_cast<AssertStmt>(node) != NULL) {
// While it's fine to run the assert for varying tests, it's not
// desirable to check an assert on a uniform variable if all of the
// lanes are off.
*okPtr = false;
return false;
}
if (llvm::dyn_cast<PrintStmt>(node) != NULL) {
*okPtr = false;
return false;
}
if (llvm::dyn_cast<NewExpr>(node) != NULL ||
llvm::dyn_cast<DeleteStmt>(node) != NULL) {
// We definitely don't want to run the uniform variants of these if
// the mask is all off. It's also worth skipping the overhead of
// executing the varying versions of them in the all-off mask case.
*okPtr = false;
return false;
}
if (llvm::dyn_cast<ForeachStmt>(node) != NULL ||
llvm::dyn_cast<ForeachActiveStmt>(node) != NULL ||
llvm::dyn_cast<ForeachUniqueStmt>(node) != NULL ||
llvm::dyn_cast<UnmaskedStmt>(node) != NULL) {
// The various foreach statements also shouldn't be run with an
// all-off mask. Since they can re-establish an 'all on' mask,
// this would be pretty unintuitive. (More generally, it's
// possibly a little strange to allow foreach in the presence of
// any non-uniform control flow...)
//
// Similarly, the implementation of foreach_unique assumes as a
// precondition that the mask won't be all off going into it, so
// we'll enforce that here...
*okPtr = false;
return false;
}
if (llvm::dyn_cast<BinaryExpr>(node) != NULL) {
BinaryExpr* binaryExpr = llvm::dyn_cast<BinaryExpr>(node);
if (binaryExpr->op == BinaryExpr::Mod || binaryExpr->op == BinaryExpr::Div) {
*okPtr = false;
return false;
}
}
IndexExpr *ie;
if ((ie = llvm::dyn_cast<IndexExpr>(node)) != NULL && ie->baseExpr != NULL) {
const Type *type = ie->baseExpr->GetType();
if (type == NULL)
return true;
if (CastType<ReferenceType>(type) != NULL)
type = type->GetReferenceTarget();
ConstExpr *ce = llvm::dyn_cast<ConstExpr>(ie->index);
if (ce == NULL) {
// indexing with a variable... -> not safe
*okPtr = false;
return false;
}
const PointerType *pointerType = CastType<PointerType>(type);
if (pointerType != NULL) {
// pointer[index] -> can't be sure -> not safe
*okPtr = false;
return false;
}
const SequentialType *seqType = CastType<SequentialType>(type);
Assert(seqType != NULL);
int nElements = seqType->GetElementCount();
if (nElements == 0) {
// Unsized array, so we can't be sure -> not safe
*okPtr = false;
return false;
}
int32_t indices[ISPC_MAX_NVEC];
int count = ce->GetValues(indices);
for (int i = 0; i < count; ++i) {
if (indices[i] < 0 || indices[i] >= nElements) {
// Index is out of bounds -> not safe
*okPtr = false;
return false;
}
}
// All indices are in-bounds
return true;
}
MemberExpr *me;
if ((me = llvm::dyn_cast<MemberExpr>(node)) != NULL &&
me->dereferenceExpr) {
*okPtr = false;
return false;
}
if (llvm::dyn_cast<PtrDerefExpr>(node) != NULL) {
*okPtr = false;
return false;
}
/*
Don't allow turning if/else to straight-line-code if we
assign to a uniform.
*/
AssignExpr *ae;
if ((ae = llvm::dyn_cast<AssignExpr>(node)) != NULL) {
if (ae->GetType()) {
if (ae->GetType()->IsUniformType()) {
*okPtr = false;
return false;
}
}
}
return true;
}
