add some hacks that fixes register pressure faithfullness of Asm nodes in common...

[r25944]

diff --git a/ir/be/ia32/ia32_common_transform.c b/ir/be/ia32/ia32_common_transform.c
index b174481..cc6a7ae 100644 (file)
--- a/ir/be/ia32/ia32_common_transform.c
+++ b/ir/be/ia32/ia32_common_transform.c
@@ -30,6 +30,7 @@
 #include "ircons.h"
 #include "irprintf.h"
 #include "typerep.h"
+#include "bitset.h"
 
 #include "../betranshlp.h"
 #include "../beirg_t.h"
@@ -436,6 +437,18 @@ static void parse_asm_constraints(constraint_t *constraint, const char *c,
        constraint->immediate_type        = immediate_type;
 }
 
+static bool can_match(const arch_register_req_t *in,
+                      const arch_register_req_t *out)
+{
+       if (in->cls != out->cls)
+               return false;
+       if ( (in->type & arch_register_req_type_limited) == 0
+               || (out->type & arch_register_req_type_limited) == 0 )
+               return true;
+
+       return (*in->limited & *out->limited) != 0;
+}
+
 ir_node *gen_ASM(ir_node *node)
 {
        ir_node                    *block = NULL;
@@ -635,6 +648,114 @@ ir_node *gen_ASM(ir_node *node)
                ++out_idx;
        }
 
+       /* Attempt to make ASM node register pressure faithfull.
+        * (This does not work for complicated cases yet!)
+        *
+        * Algorithm: Check if there are fewer inputs or outputs (I will call this
+        * the smaller list). Then try to match each constraint of the smaller list
+        * to 1 of the other list. If we can't match it, then we have to add a dummy
+        * input/output to the other list
+        *
+        * FIXME: This is still broken in lots of cases. But at least better than
+        *        before...
+        * FIXME: need to do this per register class...
+        */
+       if (out_arity <= arity) {
+               int       orig_arity = arity;
+               int       in_size    = arity;
+               int       o;
+               bitset_t *used_ins = bitset_alloca(arity);
+               for (o = 0; o < out_arity; ++o) {
+                       int   i;
+                       const arch_register_req_t *outreq = out_reg_reqs[o];
+
+                       if (outreq->cls == NULL) {
+                               continue;
+                       }
+
+                       for (i = 0; i < orig_arity; ++i) {
+                               const arch_register_req_t *inreq;
+                               if (bitset_is_set(used_ins, i))
+                                       continue;
+                               inreq = in_reg_reqs[i];
+                               if (!can_match(outreq, inreq))
+                                       continue;
+                               bitset_set(used_ins, i);
+                               break;
+                       }
+                       /* did we find any match? */
+                       if (i < orig_arity)
+                               continue;
+
+                       /* we might need more space in the input arrays */
+                       if (arity >= in_size) {
+                               const arch_register_req_t **new_in_reg_reqs;
+                               ir_node             **new_in;
+
+                               in_size *= 2;
+                               new_in_reg_reqs
+                                       = obstack_alloc(obst, in_size*sizeof(in_reg_reqs[0]));
+                               memcpy(new_in_reg_reqs, in_reg_reqs, arity * sizeof(new_in_reg_reqs[0]));
+                               new_in = ALLOCANZ(ir_node*, in_size);
+                               memcpy(new_in, in, arity*sizeof(new_in[0]));
+
+                               in_reg_reqs = new_in_reg_reqs;
+                               in          = new_in;
+                       }
+
+                       /* add a new (dummy) input which occupies the register */
+                       assert(outreq->type & arch_register_req_type_limited);
+                       in_reg_reqs[arity] = outreq;
+                       in[arity]          = new_bd_ia32_ProduceVal(NULL, block);
+                       be_dep_on_frame(in[arity]);
+                       ++arity;
+               }
+       } else {
+               int       i;
+               bitset_t *used_outs = bitset_alloca(out_arity);
+               int       orig_out_arity = out_arity;
+               int       out_size       = out_arity;
+               for (i = 0; i < arity; ++i) {
+                       int   o;
+                       const arch_register_req_t *inreq = in_reg_reqs[i];
+
+                       if (inreq->cls == NULL) {
+                               continue;
+                       }
+
+                       for (o = 0; o < orig_out_arity; ++o) {
+                               const arch_register_req_t *outreq;
+                               if (bitset_is_set(used_outs, o))
+                                       continue;
+                               outreq = out_reg_reqs[o];
+                               if (!can_match(outreq, inreq))
+                                       continue;
+                               bitset_set(used_outs, i);
+                               break;
+                       }
+                       /* did we find any match? */
+                       if (o < orig_out_arity)
+                               continue;
+
+                       /* we might need more space in the output arrays */
+                       if (out_arity >= out_size) {
+                               const arch_register_req_t **new_out_reg_reqs;
+
+                               out_size *= 2;
+                               new_out_reg_reqs
+                                       = obstack_alloc(obst, out_size*sizeof(out_reg_reqs[0]));
+                               memcpy(new_out_reg_reqs, out_reg_reqs,
+                                      out_arity * sizeof(new_out_reg_reqs[0]));
+                               out_reg_reqs = new_out_reg_reqs;
+                       }
+
+                       /* add a new (dummy) output which occupies the register */
+                       assert(inreq->type & arch_register_req_type_limited);
+                       out_reg_reqs[out_arity] = inreq;
+                       ++out_arity;
+               }
+       }
+
        new_node = new_bd_ia32_Asm(dbgi, new_block, arity, in, out_arity,
                                   get_ASM_text(node), register_map);