Set results of out-of-bounds static bit/part select to undef

diff --git a/frontends/ast/genrtlil.cc b/frontends/ast/genrtlil.cc
index ca61cb39bd2d5af8f566dd965ebdbcfb387a51a7..b4115f0cd154531389cfbcaab45ceb083e5af41a 100644 (file)
--- a/frontends/ast/genrtlil.cc
+++ b/frontends/ast/genrtlil.cc
@@ -866,6 +866,9 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
                        RTLIL::Wire *wire = NULL;
                        RTLIL::SigChunk chunk;
 
+                       int add_undef_bits_msb = 0;
+                       int add_undef_bits_lsb = 0;
+
                        if (id2ast && id2ast->type == AST_AUTOWIRE && current_module->wires_.count(str) == 0) {
                                RTLIL::Wire *wire = current_module->addWire(str);
                                wire->attributes["\\src"] = stringf("%s:%d", filename.c_str(), linenum);
@@ -919,17 +922,40 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
                                        delete fake_ast;
                                        return sig;
                                } else {
-                                       if (children[0]->range_left > id2ast->range_left || id2ast->range_right > children[0]->range_right)
-                                               log_error("Range select out of bounds on signal `%s' at %s:%d!\n",
-                                                               str.c_str(), filename.c_str(), linenum);
+                                       int source_width = id2ast->range_left - id2ast->range_right + 1;
                                        chunk.width = children[0]->range_left - children[0]->range_right + 1;
                                        chunk.offset = children[0]->range_right - id2ast->range_right;
                                        if (id2ast->range_swapped)
-                                               chunk.offset = wire->width - (chunk.offset + chunk.width);
+                                               chunk.offset = (id2ast->range_left - id2ast->range_right + 1) - (chunk.offset + chunk.width);
+                                       if (chunk.offset >= source_width || chunk.offset + chunk.width < 0) {
+                                               if (chunk.width == 1)
+                                                       log("Warning: Range select out of bounds on signal `%s' at %s:%d: Setting result bit to undef.\n",
+                                                                       str.c_str(), filename.c_str(), linenum);
+                                               else
+                                                       log("Warning: Range select out of bounds on signal `%s' at %s:%d: Setting all %d result bits to undef.\n",
+                                                                       str.c_str(), filename.c_str(), linenum, chunk.width);
+                                               chunk = RTLIL::SigChunk(RTLIL::State::Sx, chunk.width);
+                                       } else {
+                                               if (chunk.width + chunk.offset > source_width) {
+                                                       add_undef_bits_msb = (chunk.width + chunk.offset) - source_width;
+                                                       chunk.width -= add_undef_bits_msb;
+                                               }
+                                               if (chunk.offset < 0) {
+                                                       add_undef_bits_lsb = -chunk.offset;
+                                                       chunk.width -= add_undef_bits_lsb;
+                                                       chunk.offset += add_undef_bits_lsb;
+                                               }
+                                               if (add_undef_bits_lsb)
+                                                       log("Warning: Range select out of bounds on signal `%s' at %s:%d: Setting %d LSB bits to undef.\n",
+                                                                       str.c_str(), filename.c_str(), linenum, add_undef_bits_lsb);
+                                               if (add_undef_bits_msb)
+                                                       log("Warning: Range select out of bounds on signal `%s' at %s:%d: Setting %d MSB bits to undef.\n",
+                                                                       str.c_str(), filename.c_str(), linenum, add_undef_bits_msb);
+                                       }
                                }
                        }
 
-                       RTLIL::SigSpec sig(chunk);
+                       RTLIL::SigSpec sig = { RTLIL::SigSpec(RTLIL::State::Sx, add_undef_bits_msb), chunk, RTLIL::SigSpec(RTLIL::State::Sx, add_undef_bits_lsb) };
 
                        if (genRTLIL_subst_from && genRTLIL_subst_to)
                                sig.replace(*genRTLIL_subst_from, *genRTLIL_subst_to);