Avoid work in replace() if rules empty.

This speeds up processing when number of bits are large but there
is actually nothing to replace. Adresses part of #1382.

Signed-off-by: Henner Zeller <h.zeller@acm.org>

diff --git a/kernel/rtlil.cc b/kernel/rtlil.cc
index 1d380135b60af0307e0ecf08287595afeac05582..17be28f78277067d234eda60e3f243568bd4e760 100644 (file)
--- a/kernel/rtlil.cc
+++ b/kernel/rtlil.cc
@@ -3083,6 +3083,7 @@ void RTLIL::SigSpec::replace(const dict<RTLIL::SigBit, RTLIL::SigBit> &rules, RT
        log_assert(other != NULL);
        log_assert(width_ == other->width_);
 
+       if (rules.empty()) return;
        unpack();
        other->unpack();
 
@@ -3107,6 +3108,7 @@ void RTLIL::SigSpec::replace(const std::map<RTLIL::SigBit, RTLIL::SigBit> &rules
        log_assert(other != NULL);
        log_assert(width_ == other->width_);
 
+       if (rules.empty()) return;
        unpack();
        other->unpack();