[mono] Optimize boxing in Pattern Matching idioms (#32194)

* Optimize boxing in Pattern Matching

diff --git a/src/mono/mono/mini/method-to-ir.c b/src/mono/mono/mini/method-to-ir.c
index 350ce3e..aef7f43 100644 (file)
--- a/src/mono/mono/mini/method-to-ir.c
+++ b/src/mono/mono/mini/method-to-ir.c
@@ -9017,6 +9017,100 @@ calli_end:
                                        break;
                                }
                        }
+                       
+                       guint32 isinst_tk = 0;
+                       if ((ip = il_read_op_and_token (next_ip, end, CEE_ISINST, MONO_CEE_ISINST, &isinst_tk)) &&
+                               ip_in_bb (cfg, cfg->cbb, ip)) {
+                               MonoClass *isinst_class = mini_get_class (method, isinst_tk, generic_context);
+                               if (!mono_class_is_nullable (klass) && !mono_class_is_nullable (isinst_class) &&
+                                       !mini_is_gsharedvt_variable_klass (klass) && !mini_is_gsharedvt_variable_klass (isinst_class) &&
+                                       !mono_class_is_open_constructed_type (m_class_get_byval_arg (klass)) &&
+                                       !mono_class_is_open_constructed_type (m_class_get_byval_arg (isinst_class))) {
+
+                                       // Optimize
+                                       // 
+                                       //    box
+                                       //    isinst [Type]
+                                       //    brfalse/brtrue
+                                       //    
+                                       // to
+                                       // 
+                                       //    ldc.i4.0 (or 1)
+                                       //    brfalse/brtrue
+                                       //
+                                       guchar* br_ip = NULL;
+                                       if ((br_ip = il_read_brtrue (ip, end, &target)) || (br_ip = il_read_brtrue_s (ip, end, &target)) ||
+                                               (br_ip = il_read_brfalse (ip, end, &target)) || (br_ip = il_read_brfalse_s (ip, end, &target))) {
+
+                                               gboolean isinst = mono_class_is_assignable_from_internal (isinst_class, klass);
+                                               next_ip = ip;
+                                               il_op = (MonoOpcodeEnum) (isinst ? CEE_LDC_I4_1 : CEE_LDC_I4_0);
+                                               EMIT_NEW_ICONST (cfg, ins, isinst ? 1 : 0);
+                                               ins->type = STACK_I4;
+                                               *sp++ = ins;
+                                               break;
+                                       }
+
+                                       // Optimize
+                                       // 
+                                       //    box
+                                       //    isinst [Type]
+                                       //    ldnull
+                                       //    ceq/cgt.un
+                                       //    
+                                       // to
+                                       // 
+                                       //    ldc.i4.0 (or 1)
+                                       //
+                                       guchar* ldnull_ip = NULL;
+                                       if ((ldnull_ip = il_read_op (ip, end, CEE_LDNULL, MONO_CEE_LDNULL)) && ip_in_bb (cfg, cfg->cbb, ldnull_ip)) {
+                                               gboolean is_eq = FALSE, is_neq = FALSE;
+                                               if ((ip = il_read_op (ldnull_ip, end, CEE_PREFIX1, MONO_CEE_CEQ)))
+                                                       is_eq = TRUE;
+                                               else if ((ip = il_read_op (ldnull_ip, end, CEE_PREFIX1, MONO_CEE_CGT_UN)))
+                                                       is_neq = TRUE;
+
+                                               if ((is_eq || is_neq) && ip_in_bb (cfg, cfg->cbb, ip) && 
+                                                       !mono_class_is_nullable (klass) && !mini_is_gsharedvt_klass (klass)) {
+                                                       gboolean isinst = mono_class_is_assignable_from_internal (isinst_class, klass);
+                                                       next_ip = ip;
+                                                       if (is_eq)
+                                                               isinst = !isinst;
+                                                       il_op = (MonoOpcodeEnum) (isinst ? CEE_LDC_I4_1 : CEE_LDC_I4_0);
+                                                       EMIT_NEW_ICONST (cfg, ins, isinst ? 1 : 0);
+                                                       ins->type = STACK_I4;
+                                                       *sp++ = ins;
+                                                       break;
+                                               }
+                                       }
+
+                                       // Optimize
+                                       // 
+                                       //    box
+                                       //    isinst [Type]
+                                       //    unbox.any
+                                       //    
+                                       // to
+                                       // 
+                                       //    nop
+                                       //
+                                       guchar* unbox_ip = NULL;
+                                       guint32 unbox_token = 0;
+                                       if ((unbox_ip = il_read_unbox_any (ip, end, &unbox_token)) && ip_in_bb (cfg, cfg->cbb, unbox_ip)) {
+                                               MonoClass *unbox_klass = mini_get_class (method, unbox_token, generic_context);
+                                               CHECK_TYPELOAD (unbox_klass);
+                                               if (!mono_class_is_nullable (unbox_klass) &&
+                                                       !mini_is_gsharedvt_klass (unbox_klass) &&
+                                                       klass == isinst_class &&
+                                                       klass == unbox_klass)
+                                               {
+                                                       *sp++ = val;
+                                                       next_ip = unbox_ip;
+                                                       break;
+                                               }
+                                       }
+                               }
+                       }
 #endif
 
                        gboolean is_true;