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ast/simplify: Factor out helper to determine range width

This commit is contained in:
Martin Povišer 2023-04-04 11:34:17 +02:00 committed by Zachary Snow
parent cff53d6d87
commit 1ac1b2eed5
1 changed files with 43 additions and 25 deletions
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68
frontends/ast/simplify.cc
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@ -775,6 +775,33 @@ static IdentUsage always_asgn_before_use(const AstNode *node, const std::string
return IdentUsage::NotReferenced;
}
static bool try_determine_range_width(AstNode *range, int &result_width)
{
log_assert(range->type == AST_RANGE);
if (range->children.size() == 1) {
result_width = 1;
return true;
}
AstNode *left_at_zero_ast = range->children[0]->clone();
AstNode *right_at_zero_ast = range->children[1]->clone();
while (left_at_zero_ast->simplify(true, true, false, 1, -1, false, false)) {}
while (right_at_zero_ast->simplify(true, true, false, 1, -1, false, false)) {}
bool ok = false;
if (left_at_zero_ast->type == AST_CONSTANT
&& right_at_zero_ast->type == AST_CONSTANT) {
ok = true;
result_width = abs(int(left_at_zero_ast->integer - right_at_zero_ast->integer)) + 1;
}
delete left_at_zero_ast;
delete right_at_zero_ast;
return ok;
}
static const std::string auto_nosync_prefix = "\\AutoNosync";
// mark a local variable in an always_comb block for automatic nosync
@ -2788,20 +2815,13 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
AstNode *shift_expr = NULL;
AstNode *range = children[0]->children[0];
if (range->children.size() == 1) {
shift_expr = range->children[0]->clone();
} else {
if (!try_determine_range_width(range, result_width))
log_file_error(filename, location.first_line, "Unsupported expression on dynamic range select on signal `%s'!\n", str.c_str());
if (range->children.size() >= 2)
shift_expr = range->children[1]->clone();
AstNode *left_at_zero_ast = range->children[0]->clone();
AstNode *right_at_zero_ast = range->children[1]->clone();
while (left_at_zero_ast->simplify(true, true, false, stage, -1, false, false)) { }
while (right_at_zero_ast->simplify(true, true, false, stage, -1, false, false)) { }
if (left_at_zero_ast->type != AST_CONSTANT || right_at_zero_ast->type != AST_CONSTANT)
log_file_error(filename, location.first_line, "Unsupported expression on dynamic range select on signal `%s'!\n", str.c_str());
result_width = abs(int(left_at_zero_ast->integer - right_at_zero_ast->integer)) + 1;
delete left_at_zero_ast;
delete right_at_zero_ast;
}
else
shift_expr = range->children[0]->clone();
bool use_case_method = false;
@ -3205,19 +3225,20 @@ skip_dynamic_range_lvalue_expansion:;
else
{
AstNode *the_range = children[0]->children[1];
AstNode *left_at_zero_ast = the_range->children[0]->clone();
AstNode *right_at_zero_ast = the_range->children.size() >= 2 ? the_range->children[1]->clone() : left_at_zero_ast->clone();
AstNode *offset_ast = right_at_zero_ast->clone();
AstNode *offset_ast;
int width;
if (!try_determine_range_width(the_range, width))
log_file_error(filename, location.first_line, "Unsupported expression on dynamic range select on signal `%s'!\n", str.c_str());
if (the_range->children.size() >= 2)
offset_ast = the_range->children[1]->clone();
else
offset_ast = the_range->children[0]->clone();
if (mem_data_range_offset)
offset_ast = new AstNode(AST_SUB, offset_ast, mkconst_int(mem_data_range_offset, true));
while (left_at_zero_ast->simplify(true, true, false, 1, -1, false, false)) { }
while (right_at_zero_ast->simplify(true, true, false, 1, -1, false, false)) { }
if (left_at_zero_ast->type != AST_CONSTANT || right_at_zero_ast->type != AST_CONSTANT)
log_file_error(filename, location.first_line, "Unsupported expression on dynamic range select on signal `%s'!\n", str.c_str());
int width = abs(int(left_at_zero_ast->integer - right_at_zero_ast->integer)) + 1;
assign_data = new AstNode(AST_ASSIGN_EQ, new AstNode(AST_IDENTIFIER),
new AstNode(AST_SHIFT_LEFT, children[1]->clone(), offset_ast->clone()));
assign_data->children[0]->str = id_data;
@ -3229,9 +3250,6 @@ skip_dynamic_range_lvalue_expansion:;
new AstNode(AST_SHIFT_LEFT, mkconst_bits(set_bits_en, false), offset_ast->clone()));
assign_en->children[0]->str = id_en;
assign_en->children[0]->was_checked = true;
delete left_at_zero_ast;
delete right_at_zero_ast;
delete offset_ast;
}
}