Handle ternary expressions with mixed argument types.

If the true and false alternatives are mixed types, then vectored arguments are treated as if in a self-determined context then cast to REAL.
nickg · Jan 6, 2009 · 707a3eb · 707a3eb
1 parent 8eb7e4b
commit 707a3eb
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Showing 5 changed files with 82 additions and 28 deletions.
diff --git a/PExpr.h b/PExpr.h
@@ -621,6 +621,10 @@ class PETernary : public PExpr {
       virtual NetETernary*elaborate_pexpr(Design*des, NetScope*sc) const;
       virtual verinum* eval_const(Design*des, NetScope*sc) const;
 
+    private:
+      NetExpr* elab_and_eval_alternative_(Design*des, NetScope*scope,
+					  PExpr*expr, int use_wid) const;
+
     private:
       PExpr*expr_;
       PExpr*tru_;

diff --git a/elab_expr.cc b/elab_expr.cc
@@ -83,20 +83,22 @@ NetExpr* elaborate_rval_expr(Design*des, NetScope*scope,
 			     ivl_variable_type_t data_type_lv, int expr_wid_lv,
 			     PExpr*expr)
 {
-      bool unsized_flag = type_is_vectorable(data_type_lv)? false : true;
-      ivl_variable_type_t rval_type = IVL_VT_NO_TYPE;
+      bool unsized_flag     = type_is_vectorable(data_type_lv)? false : true;
+      unsigned use_lval_wid = type_is_vectorable(data_type_lv)? expr_wid_lv : 0;
+      unsigned use_min_wid  = expr_wid_lv;
 
 	/* Find out what the r-value width is going to be. We
 	guess it will be the l-value width, but it may turn
 	out to be something else based on self-determined
 	widths inside. */
-      int expr_wid = expr->test_width(des, scope, expr_wid_lv, expr_wid_lv, rval_type, unsized_flag);
+      ivl_variable_type_t rval_type = IVL_VT_NO_TYPE;
+      int expr_wid = expr->test_width(des, scope, use_min_wid, use_lval_wid, rval_type, unsized_flag);
 
       if (debug_elaborate) {
 	    cerr << expr->get_fileline() << ": debug: r-value tested "
 		 << "type=" << rval_type
 		 << ", width=" << expr_wid
-		 << ", min=" << expr_wid_lv
+		 << ", min=" << use_min_wid
 		 << ", unsized_flag=" << (unsized_flag?"true":"false") << endl;
       }
 
@@ -2799,7 +2801,7 @@ NetExpr* PEIdent::elaborate_expr_net(Design*des, NetScope*scope,
 
 unsigned PENumber::test_width(Design*, NetScope*,
 			      unsigned min, unsigned lval,
-			      ivl_variable_type_t&expr_type__,
+			      ivl_variable_type_t&use_expr_type,
 			      bool&unsized_flag)
 {
       expr_type_ = IVL_VT_LOGIC;
@@ -2813,7 +2815,7 @@ unsigned PENumber::test_width(Design*, NetScope*,
       if (lval > 0 && lval < use_wid)
 	    use_wid = lval;
 
-      expr_type__ = expr_type_;
+      use_expr_type = expr_type_;
       expr_width_ = use_wid;
       return use_wid;
 }
@@ -2866,7 +2868,7 @@ NetEConst* PEString::elaborate_expr(Design*des, NetScope*,
 
 unsigned PETernary::test_width(Design*des, NetScope*scope,
 			       unsigned min, unsigned lval,
-			       ivl_variable_type_t&expr_type__,
+			       ivl_variable_type_t&use_expr_type,
 			       bool&flag)
 {
 	// The condition of the ternary is self-determined, but we
@@ -2893,16 +2895,32 @@ unsigned PETernary::test_width(Design*des, NetScope*scope,
 	    tru_wid = tru_->test_width(des, scope, max(min,fal_wid), lval, tru_type, flag);
       }
 
-      if (tru_type == IVL_VT_REAL || fal_type == IVL_VT_REAL)
+	// If either of the alternatives is IVL_VT_REAL, then the
+	// expression as a whole is IVL_VT_REAL. Otherwise, if either
+	// of the alternatives is IVL_VT_LOGIC, then the expression as
+	// a whole is IVL_VT_LOGIC. The fallback assumes that the
+	// types are the same and we take that.
+      if (tru_type == IVL_VT_REAL || fal_type == IVL_VT_REAL) {
 	    expr_type_ = IVL_VT_REAL;
-      else if (tru_type == IVL_VT_LOGIC || fal_type == IVL_VT_LOGIC)
+	    expr_width_ = 1;
+      } else if (tru_type == IVL_VT_LOGIC || fal_type == IVL_VT_LOGIC) {
 	    expr_type_ = IVL_VT_LOGIC;
-      else
+	    expr_width_ = max(tru_wid,fal_wid);
+      } else {
+	    ivl_assert(*this, tru_type == fal_type);
 	    expr_type_ = tru_type;
+	    expr_width_ = max(tru_wid,fal_wid);
+      }
 
-      expr_width_ = max(tru_wid,fal_wid);
+      if (debug_elaborate)
+	    cerr << get_fileline() << ": debug: "
+		 << "Ternary expression type=" << expr_type_
+		 << ", width=" << expr_width_
+		 << ", unsized_flag=" << flag
+		 << " (tru_type=" << tru_type
+		 << ", fal_type=" << fal_type << ")" << endl;
 
-      expr_type__ = expr_type_;
+      use_expr_type = expr_type_;
       return expr_width_;
 }
 
@@ -2982,8 +3000,8 @@ NetExpr*PETernary::elaborate_expr(Design*des, NetScope*scope,
 			     << " of expression: " << *this << endl;
 		  }
 		  ivl_assert(*this, use_wid > 0);
-		  NetExpr*tru = elab_and_eval(des, scope, tru_, use_wid);
-		  return pad_to_width(tru, use_wid, *this);
+		  NetExpr*tmp = elab_and_eval_alternative_(des, scope, tru_, use_wid);
+		  return pad_to_width(tmp, use_wid, *this);
 	    }
 
 	      // Condition is constant FALSE, so we only need the
@@ -3000,21 +3018,21 @@ NetExpr*PETernary::elaborate_expr(Design*des, NetScope*scope,
 			     << " of expression: " << *this << endl;
 		  }
 		  ivl_assert(*this, use_wid > 0);
-		  NetExpr*fal = elab_and_eval(des, scope, fal_, use_wid);
-		  return pad_to_width(fal, use_wid, *this);
+		  NetExpr*tmp = elab_and_eval_alternative_(des, scope, fal_, use_wid);
+		  return pad_to_width(tmp, use_wid, *this);
 	    }
 
 	      // X and Z conditions need to blend both results, so we
 	      // can't short-circuit.
       }
 
-      NetExpr*tru = elab_and_eval(des, scope, tru_, use_wid);
+      NetExpr*tru = elab_and_eval_alternative_(des, scope, tru_, use_wid);
       if (tru == 0) {
 	    delete con;
 	    return 0;
       }
 
-      NetExpr*fal = elab_and_eval(des, scope, fal_, use_wid);
+      NetExpr*fal = elab_and_eval_alternative_(des, scope, fal_, use_wid);
       if (fal == 0) {
 	    delete con;
 	    delete tru;
@@ -3042,6 +3060,22 @@ NetExpr*PETernary::elaborate_expr(Design*des, NetScope*scope,
       return res;
 }
 
+/*
+ * When elaborating the true or false alternative expression of a
+ * ternary, take into account the overall expression type. If the type
+ * is not vectorable, then the alternative expression is evaluated as
+ * self-determined.
+ */
+NetExpr* PETernary::elab_and_eval_alternative_(Design*des, NetScope*scope,
+					       PExpr*expr, int use_wid) const
+{
+      if (type_is_vectorable(expr->expr_type()) && !type_is_vectorable(expr_type_)) {
+	    return elab_and_eval(des, scope, expr, -1);
+      }
+
+      return elab_and_eval(des, scope, expr, use_wid);
+}
+
 unsigned PEUnary::test_width(Design*des, NetScope*scope,
 			     unsigned min, unsigned lval,
 			     ivl_variable_type_t&expr_type__,

diff --git a/eval_tree.cc b/eval_tree.cc
@@ -1484,7 +1484,9 @@ NetExpr* NetETernary::eval_tree(int prune_to_width)
 		       << "constant condition value: ";
 		  print_ternary_cond(cond_);
 		  cerr << get_fileline() << ":      : Blending real cases "
-		       << "to get " << val << endl;
+		       << "true=" << tv.as_double()
+		       << ", false=" << fv.as_double()
+		       << ", to get " << val << endl;
 	    }
 
 	    NetECReal*rc = new NetECReal(val);

diff --git a/expr_synth.cc b/expr_synth.cc
@@ -1184,12 +1184,21 @@ NetNet* NetETernary::synthesize(Design *des, NetScope*scope, NetExpr*root)
       osig->data_type(expr_type());
       osig->local_flag(true);
 
+	/* Make sure the types match. */
+      if (expr_type() == IVL_VT_REAL) {
+	    tsig = cast_to_real(des, scope, tsig);
+	    fsig = cast_to_real(des, scope, fsig);
+
+      }
+
 	/* Make sure both value operands are the right width. */
-      tsig = crop_to_width(des, pad_to_width(des, tsig, width, *this), width);
-      fsig = crop_to_width(des, pad_to_width(des, fsig, width, *this), width);
+      if (type_is_vectorable(expr_type())) {
+	    tsig = crop_to_width(des, pad_to_width(des, tsig, width, *this), width);
+	    fsig = crop_to_width(des, pad_to_width(des, fsig, width, *this), width);
+	    ivl_assert(*this, width == tsig->vector_width());
+	    ivl_assert(*this, width == fsig->vector_width());
+      }
 
-      assert(width == tsig->vector_width());
-      assert(width == fsig->vector_width());
 
       perm_string oname = csig->scope()->local_symbol();
       NetMux *mux = new NetMux(csig->scope(), oname, width,

diff --git a/netlist.cc b/netlist.cc
@@ -2270,11 +2270,16 @@ ivl_variable_type_t NetESignal::expr_type() const
 NetETernary::NetETernary(NetExpr*c, NetExpr*t, NetExpr*f)
 : cond_(c), true_val_(t), false_val_(f)
 {
-	// use widest result
-      if (true_val_->expr_width() > false_val_->expr_width())
-            expr_width(true_val_->expr_width());
-      else
-            expr_width(false_val_->expr_width());
+      if (type_is_vectorable(expr_type())) {
+	      // use widest result
+	    if (true_val_->expr_width() > false_val_->expr_width())
+		  expr_width(true_val_->expr_width());
+	    else
+		  expr_width(false_val_->expr_width());
+      } else {
+	    expr_width(1);
+      }
+
       cast_signed(c->has_sign() && t->has_sign() && f->has_sign());
 }