* mini.c:

	move_basic_block_to_end: Add branches when needed, eventually creating
	a new BB.
	optimize_branches: added a parameter that tells if it's ok to create
	new BBs (doing is "df_visit" has been called is (IMHO) a nightmare),
	and avoid calling move_basic_block_to_end when it's not ok.
	Fixes bug 318677.

svn path=/trunk/mono/; revision=89121

diff --git a/mono/mini/ChangeLog b/mono/mini/ChangeLog
index 883c42f96f57c55f4fa3a2e407810b051384f846..ada9efa2e851a9e38271472496362e6ba7f371db 100644 (file)
--- a/mono/mini/ChangeLog
+++ b/mono/mini/ChangeLog
@@ -1,3 +1,13 @@
+2007-11-07  Massimiliano Mantione  <massi@ximian.com>
+
+       * mini.c:
+       move_basic_block_to_end: Add branches when needed, eventually creating
+       a new BB.
+       optimize_branches: added a parameter that tells if it's ok to create
+       new BBs (doing is "df_visit" has been called is (IMHO) a nightmare),
+       and avoid calling move_basic_block_to_end when it's not ok.
+       Fixes bug 318677.
+
 2007-11-07  Mark Probst  <mark.probst@gmail.com>
 
        * mini.c: Abort inlining call to InitializeArray if something

diff --git a/mono/mini/mini.c b/mono/mini/mini.c
index 8897ca7f594e17480f1c704d993fc3a20c84336e..53e8fbaef613fb09bd86942452ca1798b506a21c 100644 (file)
--- a/mono/mini/mini.c
+++ b/mono/mini/mini.c
@@ -9773,6 +9773,56 @@ move_basic_block_to_end (MonoCompile *cfg, MonoBasicBlock *bb)
        for (bbn = cfg->bb_entry; bbn->next_bb && bbn->next_bb != bb; bbn = bbn->next_bb)
                ;
        if (bbn->next_bb) {
+               MonoInst *last_ins = bbn->last_ins;
+
+               if (last_ins != NULL) {
+                       if (! MONO_IS_BRANCH_OP (last_ins)) {
+                               MonoInst *ins;
+                               MONO_INST_NEW (cfg, ins, OP_BR);
+                               MONO_ADD_INS (bbn, ins);
+                               link_bblock (cfg, bbn, bbn->next_bb);
+                               ins->inst_target_bb = bbn->next_bb;
+                               
+                               if (cfg->verbose_level > 2)
+                                       printf ("move_basic_block_to_end linked BB %d to BB %d with a branch\n", bbn->block_num, bbn->next_bb->block_num);
+                       } else if (last_ins->opcode == CEE_SWITCH) {
+                               /* See bug #318677 for an explanation... */
+                               MonoBasicBlock *new_bb;
+                               MonoInst *ins;
+                               
+                               /* Create block */
+                               new_bb = NEW_BBLOCK (cfg);
+                               new_bb->real_offset = bbn->real_offset;
+                               new_bb->cil_code = bbn->cil_code;
+                               new_bb->region = bbn->region;
+                               new_bb->block_num = cfg->num_bblocks++;
+                               
+                               /* Create branch */
+                               MONO_INST_NEW (cfg, ins, OP_BR);
+                               MONO_ADD_INS (new_bb, ins);
+                               ins->inst_target_bb = bbn->next_bb;
+                               
+                               /* Link all blocks */
+                               link_bblock (cfg, bbn, new_bb);
+                               link_bblock (cfg, new_bb, bbn->next_bb);
+                               
+                               if (cfg->verbose_level > 2)
+                                       printf ("move_basic_block_to_end linked BB %d to BB %d with a branch\n", bbn->block_num, bbn->next_bb->block_num);
+                               
+                               /* Insert new block into the list */
+                               bbn->next_bb = new_bb;
+                               bbn = new_bb;
+                       }
+               } else {
+                       MonoInst *ins;
+                       MONO_INST_NEW (cfg, ins, OP_BR);
+                       MONO_ADD_INS (bbn, ins);
+                       link_bblock (cfg, bbn, bbn->next_bb);
+                       ins->inst_target_bb = bbn->next_bb;
+                       if (cfg->verbose_level > 2)
+                               printf ("move_basic_block_to_end linked empty BB %d to BB %d with a branch\n", bbn->block_num, bbn->next_bb->block_num);
+               }
+
                bbn->next_bb = bb->next_bb;
        }
 
@@ -9901,7 +9951,7 @@ try_unsigned_compare (MonoCompile *cfg, MonoBasicBlock *bb)
  *
  */
 static void
-optimize_branches (MonoCompile *cfg)
+optimize_branches (MonoCompile *cfg, gboolean can_create_blocks)
 {
        int i, changed = FALSE;
        MonoBasicBlock *bb, *bbn;
@@ -10101,7 +10151,7 @@ optimize_branches (MonoCompile *cfg)
                                        }
                                }
 
-                               if (bb->last_ins && MONO_IS_COND_BRANCH_NOFP (bb->last_ins)) {
+                               if (bb->last_ins && MONO_IS_COND_BRANCH_NOFP (bb->last_ins) && can_create_blocks) {
                                        if (bb->last_ins->inst_false_bb->out_of_line && (bb->region == bb->last_ins->inst_false_bb->region)) {
                                                /* Reverse the branch */
                                                bb->last_ins->opcode = reverse_branch_op (bb->last_ins->opcode);
@@ -10755,7 +10805,7 @@ mini_method_compile (MonoMethod *method, guint32 opts, MonoDomain *domain, gbool
        /*g_print ("numblocks = %d\n", cfg->num_bblocks);*/
 
        if (cfg->opt & MONO_OPT_BRANCH)
-               optimize_branches (cfg);
+               optimize_branches (cfg, TRUE);
 
        if (cfg->opt & MONO_OPT_SSAPRE) {
                remove_critical_edges (cfg);
@@ -10853,7 +10903,7 @@ mini_method_compile (MonoMethod *method, guint32 opts, MonoDomain *domain, gbool
                mono_ssa_remove (cfg);
 
                if (cfg->opt & MONO_OPT_BRANCH)
-                       optimize_branches (cfg);
+                       optimize_branches (cfg, FALSE);
        }
 
        /* after SSA removal */