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ast/simplify: Use clone_at_zero() for "at_zero" evaluations

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The correct way of using the 'at_zero' regime of simplify is to perform
the simplification on a cloned AST subtree, otherwise the "at_zero"
evaluation seeps into the main tree.

Move the effect of the 'at_zero' flag to the cloning itself, so that
the simplify flag can be retired. We assume we can rely on id2ast in
the new clone method.
This commit is contained in:
Martin Povišer 2023-06-21 13:45:42 +02:00 • committed by Zachary Snow
parent 77d4b5230e
commit 4fceeb3b32
3 changed files with 56 additions and 22 deletions
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16
frontends/ast/genrtlil.cc
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@ -887,10 +887,10 @@ void AstNode::detectSignWidthWorker(int &width_hint, bool &sign_hint, bool *foun
if (range->children.size() == 1)
this_width = 1;
else if (!range->range_valid) {
AstNode *left_at_zero_ast = children[0]->children[0]->clone();
AstNode *right_at_zero_ast = children[0]->children.size() >= 2 ? children[0]->children[1]->clone() : left_at_zero_ast->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)) { }
AstNode *left_at_zero_ast = children[0]->children[0]->clone_at_zero();
AstNode *right_at_zero_ast = children[0]->children.size() >= 2 ? children[0]->children[1]->clone_at_zero() : left_at_zero_ast->clone();
while (left_at_zero_ast->simplify(true, false, false, 1, -1, false, false)) { }
while (right_at_zero_ast->simplify(true, false, false, 1, -1, false, false)) { }
if (left_at_zero_ast->type != AST_CONSTANT || right_at_zero_ast->type != AST_CONSTANT)
input_error("Unsupported expression on dynamic range select on signal `%s'!\n", str.c_str());
this_width = abs(int(left_at_zero_ast->integer - right_at_zero_ast->integer)) + 1;
@ -1460,10 +1460,10 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
}
if (!children[0]->range_valid) {
AstNode *left_at_zero_ast = children[0]->children[0]->clone();
AstNode *right_at_zero_ast = children[0]->children.size() >= 2 ? children[0]->children[1]->clone() : left_at_zero_ast->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)) { }
AstNode *left_at_zero_ast = children[0]->children[0]->clone_at_zero();
AstNode *right_at_zero_ast = children[0]->children.size() >= 2 ? children[0]->children[1]->clone_at_zero() : left_at_zero_ast->clone();
while (left_at_zero_ast->simplify(true, false, false, 1, -1, false, false)) { }
while (right_at_zero_ast->simplify(true, false, false, 1, -1, false, false)) { }
if (left_at_zero_ast->type != AST_CONSTANT || right_at_zero_ast->type != AST_CONSTANT)
input_error("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;