From: Ulya Trofimovich <skvadrik@gmail.com>
Date: Wed, 5 Apr 2017 20:56:44 +0000 (+0100)
Subject: Fixed tag optimizations to respect tags with history.
X-Git-Tag: 1.0~39^2~82
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=503b39386750237dea74e7d6e550df52af0671ab;p=re2c

Fixed tag optimizations to respect tags with history.
---

diff --git a/re2c/src/dfa/cfg/compact.cc b/re2c/src/dfa/cfg/compact.cc
index fcd06820..fe7ce413 100644
--- a/re2c/src/dfa/cfg/compact.cc
+++ b/re2c/src/dfa/cfg/compact.cc
@@ -19,10 +19,13 @@ tagver_t cfg_t::compact(const cfg_t &cfg, tagver_t *ver2new)
 	for (size_t i = 0; i < cfg.nbbfall; ++i) {
 		const cfg_bb_t &b = cfg.bblocks[i];
 		for (const tcmd_t *p = b.cmd; p; p = p->next) {
-			const tagver_t r = p->rhs;
+			const tagver_t r = p->rhs, h = p->pred;
 			if (tcmd_t::iscopy(r)) {
 				used[r] = true;
 			}
+			if (h != TAGVER_ZERO) {
+				used[h] = true;
+			}
 			used[p->lhs] = true;
 		}
 	}
diff --git a/re2c/src/dfa/cfg/interfere.cc b/re2c/src/dfa/cfg/interfere.cc
index a83961f1..aedf6576 100644
--- a/re2c/src/dfa/cfg/interfere.cc
+++ b/re2c/src/dfa/cfg/interfere.cc
@@ -38,15 +38,11 @@ void interfere(const tcmd_t *cmd, const bool *live, bool *interf,
 		cfg_t::live_through_bblock(p->next, buf2);
 
 		// exclude RHS
-		if (tcmd_t::iscopy(r)) {
-			buf2[r] = false;
-		}
+		if (tcmd_t::iscopy(r)) buf2[r] = false;
 
 		// exclude tags assigned to the same RHS
 		for (const tcmd_t *q = cmd; q; q = q->next) {
-			if (q->rhs == r) {
-				buf2[q->lhs] = false;
-			}
+			if (q->rhs == r) buf2[q->lhs] = false;
 		}
 
 		const size_t l = static_cast<size_t>(p->lhs);
diff --git a/re2c/src/dfa/cfg/liveanal.cc b/re2c/src/dfa/cfg/liveanal.cc
index efe65d9e..f03b3783 100644
--- a/re2c/src/dfa/cfg/liveanal.cc
+++ b/re2c/src/dfa/cfg/liveanal.cc
@@ -29,11 +29,17 @@ void cfg_t::live_through_bblock(const tcmd_t *cmd, bool *live)
 
 	live_through_bblock(cmd->next, live);
 
-	const tagver_t l = cmd->lhs, r = cmd->rhs;
-	if (live[l] && tcmd_t::iscopy(r)) {
-		live[r] = true;
+	const tagver_t l = cmd->lhs, r = cmd->rhs, p = cmd->pred;
+	if (live[l]) {
+		// first reset, than set: LHS might be equal to history
+		live[l] = false;
+		if (tcmd_t::iscopy(r)) {
+			live[r] = true;
+		}
+		if (p != TAGVER_ZERO) {
+			live[p] = true;
+		}
 	}
-	live[l] = false;
 }
 
 void cfg_t::liveness_analysis(const cfg_t &cfg, bool *live)
diff --git a/re2c/src/dfa/cfg/rename.cc b/re2c/src/dfa/cfg/rename.cc
index 56c475a8..25cb5250 100644
--- a/re2c/src/dfa/cfg/rename.cc
+++ b/re2c/src/dfa/cfg/rename.cc
@@ -12,12 +12,15 @@ void cfg_t::renaming(cfg_t &cfg, const tagver_t *ver2new, tagver_t maxver)
 	cfg_bb_t *b = cfg.bblocks, *be = b + cfg.nbbfall;
 	for (; b < be; ++b) {
 		for (tcmd_t *p, **pp = &b->cmd; (p = *pp);) {
-			tagver_t &l = p->lhs, &r = p->rhs;
+			tagver_t &l = p->lhs, &r = p->rhs, &h = p->pred;
 
 			l = ver2new[l];
 			if (tcmd_t::iscopy(r)) {
 				r = ver2new[r];
 			}
+			if (h != TAGVER_ZERO) {
+				h = ver2new[h];
+			}
 			if (l == r) {
 				*pp = p->next;
 			} else {
diff --git a/re2c/src/dfa/cfg/varalloc.cc b/re2c/src/dfa/cfg/varalloc.cc
index f92249ba..a50027c8 100644
--- a/re2c/src/dfa/cfg/varalloc.cc
+++ b/re2c/src/dfa/cfg/varalloc.cc
@@ -35,7 +35,8 @@ tagver_t cfg_t::variable_allocation(const cfg_t &cfg, const bool *interf,
 		for (const tcmd_t *p = b->cmd; p; p = p->next) {
 			x = p->lhs;
 			y = p->rhs;
-			if (!tcmd_t::iscopy(y)) continue;
+			if (!tcmd_t::iscopy(y)) y = p->pred;
+			if (y == TAGVER_ZERO || y == x) continue;
 
 			rx = repr[x];
 			ry = repr[y];