LLVMDoubleVisitor init is slow, added example as benchmark

benchmarks/CMakeLists.txt

@@ -85,3 +85,9 @@ target_link_libraries(parsing symengine)
 
 add_executable(diff_cache diff_cache.cpp)
 target_link_libraries(diff_cache symengine)
+
+if (WITH_LLVM)
+    add_executable(llvm_diff_cache llvm_diff_cache.cpp)
+    target_link_libraries(llvm_diff_cache symengine)
+endif()
+

benchmarks/llvm_diff_cache.cpp

@@ -0,0 +1,134 @@
+#include <iostream>
+#include <chrono>
+#include <iomanip>
+
+#include <symengine/basic.h>
+#include <symengine/add.h>
+#include <symengine/symbol.h>
+#include <symengine/integer.h>
+#include <symengine/mul.h>
+#include <symengine/pow.h>
+#include <symengine/functions.h>
+#include <symengine/llvm_double.h>
+#include <symengine/eval_mpfr.h>
+using SymEngine::LLVMDoubleVisitor;
+
+using SymEngine::Basic;
+using SymEngine::RCP;
+using SymEngine::add;
+using SymEngine::symbol;
+using SymEngine::integer;
+using SymEngine::log;
+using SymEngine::sin;
+using SymEngine::pow;
+using SymEngine::sqrt;
+using SymEngine::Symbol;
+using SymEngine::rcp_static_cast;
+using SymEngine::free_symbols;
+using SymEngine::DenseMatrix;
+
+double CommonSubexprLLVM()
+{
+    RCP<const Basic> e;
+
+    std::string tmp_str = "a";
+    std::vector<RCP<const Basic>> v;
+    for (int i = 0; i < 1000; ++i) {
+        v.push_back(symbol(tmp_str));
+        tmp_str += "a";
+    }
+
+    e = integer(23);
+    for (unsigned int i = 0; i < v.size(); ++i) {
+        RCP<const Basic> z = symbol(tmp_str);
+        e = pow(e, add(cos(sqrt(log(sin(pow(v[v.size() - i - 1], v[i]))))), e));
+    }
+    e = expand(e);
+
+    DenseMatrix M, J, S;
+    M = DenseMatrix(1, 1, {e});
+    S = DenseMatrix(10, 1, v);
+    J = DenseMatrix(1, 10);
+
+    auto t1 = std::chrono::high_resolution_clock::now();
+    jacobian(M, S, J);
+    auto t2 = std::chrono::high_resolution_clock::now();
+
+    std::cout
+        << "Time for jacobian with common subexpressions (with cache) : \t "
+        << std::setw(15) << std::setprecision(9) << std::fixed
+        << std::chrono::duration<double>(t2 - t1).count() << std::endl;
+
+    t1 = std::chrono::high_resolution_clock::now();
+
+    LLVMDoubleVisitor v3;
+    bool symbolic_cse = true;
+    int opt_level = 3;
+    v3.init(v,
+            {J.get(0, 0), J.get(0, 1), J.get(0, 2), J.get(0, 3), J.get(0, 4),
+             J.get(0, 5), J.get(0, 6), J.get(0, 7), J.get(0, 8), J.get(0, 9)},
+            symbolic_cse, opt_level);
+    t2 = std::chrono::high_resolution_clock::now();
+    std::cout
+        << "Time for llvm init with common subexpressions (with cache) : \t "
+        << std::setw(15) << std::setprecision(9) << std::fixed
+        << std::chrono::duration<double>(t2 - t1).count() << std::endl;
+    return 0;
+}
+
+double NoCommonSubexprLLVM()
+{
+    RCP<const Basic> e;
+
+    std::string tmp_str = "a";
+    std::vector<RCP<const Basic>> v;
+    for (int i = 0; i < 2000; ++i) {
+        v.push_back(symbol(tmp_str));
+        tmp_str += "a";
+    }
+
+    e = integer(23);
+    for (unsigned int i = 0; i < v.size(); ++i) {
+        RCP<const Basic> z = symbol(tmp_str);
+        e = pow(e, cos(sqrt(log(sin(pow(v[v.size() - i - 1], v[i]))))));
+    }
+    e = expand(e);
+
+    DenseMatrix M, J, S;
+    M = DenseMatrix(1, 1, {e});
+    S = DenseMatrix(10, 1, v);
+    J = DenseMatrix(1, 10);
+
+    auto t1 = std::chrono::high_resolution_clock::now();
+    jacobian(M, S, J, false);
+    auto t2 = std::chrono::high_resolution_clock::now();
+
+    std::cout << "Time for jacobian without common subexpressions (without "
+                 "cache) : \t "
+              << std::setw(15) << std::setprecision(9) << std::fixed
+              << std::chrono::duration<double>(t2 - t1).count() << std::endl;
+
+    t1 = std::chrono::high_resolution_clock::now();
+
+    LLVMDoubleVisitor v3;
+    bool symbolic_cse = true;
+    int opt_level = 3;
+    v3.init(v,
+            {J.get(0, 0), J.get(0, 1), J.get(0, 2), J.get(0, 3), J.get(0, 4),
+             J.get(0, 5), J.get(0, 6), J.get(0, 7), J.get(0, 8), J.get(0, 9)},
+            symbolic_cse, opt_level);
+    t2 = std::chrono::high_resolution_clock::now();
+    std::cout << "Time for llvm init without common subexpressions (without "
+                 "cache) : \t "
+              << std::setw(15) << std::setprecision(9) << std::fixed
+              << std::chrono::duration<double>(t2 - t1).count() << std::endl;
+    return 0;
+}
+
+int main(int argc, char *argv[])
+{
+    SymEngine::print_stack_on_segfault();
+    CommonSubexprLLVM();
+    NoCommonSubexprLLVM();
+    return 0;
+}