[PPL-devel] [GIT] ppl/ppl(master): Avoid useless allocations by only adding recycled rows to Bit_Matrix.

[Roberto Bagnara]

Module: ppl/ppl
Branch: master
Commit: 73047e08667ebca99b0262dd03c07f100f3c2925
URL:    http://www.cs.unipr.it/git/gitweb.cgi?p=ppl/ppl.git;a=commit;h=73047e08667ebca99b0262dd03c07f100f3c2925

Author: Roberto Bagnara <bagnara at cs.unipr.it>
Date:   Mon Apr 20 12:18:05 2009 +0200

Avoid useless allocations by only adding recycled rows to Bit_Matrix.

---

 src/Bit_Matrix.cc      |    9 +++++----
 src/Bit_Matrix.defs.hh |    8 +++++++-
 src/conversion.cc      |    4 ++--
 3 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/src/Bit_Matrix.cc b/src/Bit_Matrix.cc
index ac126c5..dbce634 100644
--- a/src/Bit_Matrix.cc
+++ b/src/Bit_Matrix.cc
@@ -55,7 +55,7 @@ PPL::Bit_Matrix::sort_rows() {
 }
 
 void
-PPL::Bit_Matrix::add_row(const Bit_Row& row) {
+PPL::Bit_Matrix::add_recycled_row(Bit_Row& row) {
   const dimension_type new_rows_size = rows.size() + 1;
   if (rows.capacity() < new_rows_size) {
     // Reallocation will take place.
@@ -64,7 +64,7 @@ PPL::Bit_Matrix::add_row(const Bit_Row& row) {
     new_rows.insert(new_rows.end(), new_rows_size, Bit_Row());
     // Put the new row in place.
     dimension_type i = new_rows_size-1;
-    new_rows[i] = row;
+    new_rows[i].swap(row);
     // Steal the old rows.
     while (i-- > 0)
       new_rows[i].swap(rows[i]);
@@ -72,8 +72,9 @@ PPL::Bit_Matrix::add_row(const Bit_Row& row) {
     std::swap(rows, new_rows);
   }
   else
-    // Reallocation will NOT take place: append a new empty row.
-    rows.push_back(row);
+    // Reallocation will NOT take place: append an empty row
+    // and swap it with the new row.
+    rows.insert(rows.end(), Bit_Row())->swap(row);
   assert(OK());
 }
 
diff --git a/src/Bit_Matrix.defs.hh b/src/Bit_Matrix.defs.hh
index 82f4b4f..c460924 100644
--- a/src/Bit_Matrix.defs.hh
+++ b/src/Bit_Matrix.defs.hh
@@ -94,7 +94,13 @@ public:
   bool sorted_contains(const Bit_Row& row) const;
 
   //! Adds \p row to \p *this.
-  void add_row(const Bit_Row& row);
+  /*!
+    \param row
+    The row whose implementation will be recycled.
+
+    The only thing that can be done with \p row upon return is destruction.
+  */
+  void add_recycled_row(Bit_Row& row);
 
   //! Erases the rows from the \p first_to_erase -th to the last one.
   void rows_erase_to_end(dimension_type first_to_erase);
diff --git a/src/conversion.cc b/src/conversion.cc
index ec581f7..7c0b04b 100644
--- a/src/conversion.cc
+++ b/src/conversion.cc
@@ -721,10 +721,10 @@ PPL::Polyhedron::conversion(Linear_System& source,
 		    // Make room for one more row.
 		    dest.add_pending_row(Linear_Row::Flags(dest.topology(),
 							   Linear_Row::RAY_OR_POINT_OR_INEQUALITY));
-		    sat.add_row(new_satrow);
+		    sat.add_recycled_row(new_satrow);
 		  }
 		  else
-		    sat[dest_num_rows] = new_satrow;
+                    sat[dest_num_rows].swap(new_satrow);
 
 		  Linear_Row& new_row = dest[dest_num_rows];
 		  // The following fragment optimizes the computation of