From 93d7b98f2c35d2455c75b4bb6322228bb9cea108 Mon Sep 17 00:00:00 2001
From: Ulya Trofimovich <skvadrik@gmail.com>
Date: Wed, 8 May 2019 10:54:00 +0100
Subject: [PATCH] Make unreachable rule analysis conditional to further sppedup
 closure pruning.

---
 src/dfa/closure.cc | 16 +++++++++-------
 src/msg/warn.cc    |  5 +++++
 src/msg/warn.h     |  1 +
 3 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/src/dfa/closure.cc b/src/dfa/closure.cc
index a5082a0c..c3b7ba51 100644
--- a/src/dfa/closure.cc
+++ b/src/dfa/closure.cc
@@ -132,8 +132,8 @@ template<typename ctx_t>
 void prune(ctx_t &ctx)
 {
     // Filter out configurations which states have transitions on symbols.
-    // If any configurations with final state, pick one with the lowest rule.
-    // See note [at most one final item per closure].
+    // If we have any configurations with final state, pick the one with
+    // the lowest rule. See note [at most one final item per closure].
 
     closure_t &closure = ctx.state, &buffer = ctx.reach;
     clositer_t b = closure.begin(), e = closure.end(), i, f = e;
@@ -154,11 +154,13 @@ void prune(ctx_t &ctx)
         buffer.push_back(*f);
 
         // mark dropped rules as shadowed
-        std::valarray<Rule> &rules = ctx.nfa.rules;
-        const uint32_t l = rules[f->state->rule].code->loc.line;
-        for (i = b; i != e; ++i) {
-            if (i != f && i->state->type == nfa_state_t::FIN) {
-                rules[i->state->rule].shadow.insert(l);
+        if (ctx.dc_msg.warn.is_set(Warn::UNREACHABLE_RULES)) {
+            std::valarray<Rule> &rules = ctx.nfa.rules;
+            const uint32_t l = rules[f->state->rule].code->loc.line;
+            for (i = b; i != e; ++i) {
+                if (i != f && i->state->type == nfa_state_t::FIN) {
+                    rules[i->state->rule].shadow.insert(l);
+                }
             }
         }
     }
diff --git a/src/msg/warn.cc b/src/msg/warn.cc
index 1fb8a51d..83d02105 100644
--- a/src/msg/warn.cc
+++ b/src/msg/warn.cc
@@ -75,6 +75,11 @@ void Warn::set_all_error ()
     }
 }
 
+bool Warn::is_set(type_t t) const
+{
+    return mask[t] > 0;
+}
+
 void Warn::fail(type_t t, const loc_t &loc, const char *s) const
 {
     if (mask[t] & WARNING) {
diff --git a/src/msg/warn.h b/src/msg/warn.h
index 2168b0c4..949bdeb2 100644
--- a/src/msg/warn.h
+++ b/src/msg/warn.h
@@ -59,6 +59,7 @@ public:
     void set (type_t t, option_t o);
     void set_all ();
     void set_all_error ();
+    bool is_set(type_t t) const;
     void fail(type_t t, const loc_t &loc, const char *s) const;
 
     void condition_order(const loc_t &loc);
-- 
2.50.1