[interp] Handle more cases for stloc.np optimization

We emit stloc.np if we have "stloc local; ldloc local". Bu we can also emit if we have "stloc loc1; ldloc loc2" and loc2 == loc1.

Commit migrated from https://github.com/mono/mono/commit/f2006f61dc763cf8f8fd7f56743d7cd40f2f22c8

diff --git a/src/mono/mono/mini/interp/transform.c b/src/mono/mono/mini/interp/transform.c
index c1de2a6..0ec3fe6 100644 (file)
--- a/src/mono/mono/mini/interp/transform.c
+++ b/src/mono/mono/mini/interp/transform.c
@@ -6387,6 +6387,26 @@ interp_local_deadce (TransformData *td, int *local_ref_count)
        }
 }
 
+static gboolean
+interp_local_equal (StackValue *locals, int local1, int local2)
+{
+       if (local1 == local2)
+               return TRUE;
+       if (locals [local1].opcode != MINT_NOP) {
+               g_assert (MINT_IS_LDLOC (locals [local1].opcode));
+               // local1 is a copy of local2
+               if (locals [local1].data == local2)
+                       return TRUE;
+       }
+       if (locals [local2].opcode != MINT_NOP) {
+               g_assert (MINT_IS_LDLOC (locals [local2].opcode));
+               // local2 is a copy of local1
+               if (locals [local2].data == local1)
+                       return TRUE;
+       }
+       return FALSE;
+}
+
 static void
 interp_cprop (TransformData *td)
 {
@@ -6424,7 +6444,7 @@ interp_cprop (TransformData *td)
                        int loaded_local = ins->data [0];
                        local_ref_count [loaded_local]++;
                        InterpInst *prev_ins = interp_prev_ins (ins);
-                       if (MINT_IS_STLOC (prev_ins->opcode) && !interp_is_bb_start (td, prev_ins, ins) && prev_ins->data [0] == loaded_local) {
+                       if (MINT_IS_STLOC (prev_ins->opcode) && !interp_is_bb_start (td, prev_ins, ins) && interp_local_equal (locals, prev_ins->data [0], loaded_local)) {
                                int mt = prev_ins->opcode - MINT_STLOC_I1;
                                if (ins->opcode - MINT_LDLOC_I1 == mt) {
                                        if (mt == MINT_TYPE_I4)
@@ -6432,16 +6452,18 @@ interp_cprop (TransformData *td)
                                        else if (mt == MINT_TYPE_O || mt == MINT_TYPE_P)
                                                replace_op = MINT_STLOC_NP_O;
                                        if (replace_op) {
+                                               int stored_local = prev_ins->data [0];
                                                if (td->verbose_level)
                                                        g_print ("Add stloc.np : ldloc (off %p), stloc (off %p)\n", ins->il_offset, prev_ins->il_offset);
                                                // We know what local is on the stack now. Track it
                                                sp->ins = NULL;
                                                sp->val.opcode = ins->opcode;
-                                               sp->val.data = loaded_local;
+                                               sp->val.data = stored_local;
 
                                                // Clear the previous stloc instruction
                                                interp_clear_ins (td, prev_ins);
                                                ins->opcode = replace_op;
+                                               ins->data [0] = stored_local;
                                                mono_interp_stats.stloc_nps++;
                                                local_ref_count [loaded_local]--;
                                        }