pan/bi: Add phi nodes

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17794>

src/panfrost/bifrost/ISA.xml

@@ -8854,6 +8854,8 @@
     </mod>
   </ins>
 
+  <ins name="+PHI" pseudo="true" variable_srcs="true"/>
+
   <ins name="+COLLECT.i32" pseudo="true" variable_srcs="true"/>
 
   <ins name="+SPLIT.i32" pseudo="true" variable_dests="true">

src/panfrost/bifrost/bi_printer.c.py

@@ -179,7 +179,7 @@ bi_print_instr(const bi_instr *I, FILE *fp)
     if (I->flow)
         fprintf(fp, ".flow%u", I->flow);
 
-    if (I->op == BI_OPCODE_COLLECT_I32) {
+    if (I->op == BI_OPCODE_COLLECT_I32 || I->op == BI_OPCODE_PHI) {
         for (unsigned i = 0; i < I->nr_srcs; ++i) {
             if (i > 0)
                 fputs(", ", fp);