Added some heuristic for register spilling

[fw/sdcc] / src / pic / ralloc.c

diff --git a/src/pic/ralloc.c b/src/pic/ralloc.c
index 47f44544a40ba9a9e07ec2192384fb6af06f33c8..af761485bf0f19e7a3eb070e818d1a4b521041da 100644 (file)
--- a/src/pic/ralloc.c
+++ b/src/pic/ralloc.c
@@ -1554,19 +1554,21 @@ serialRegAssign (eBBlock ** ebbs, int count)
 
              /* if it has a spillocation & is used less than
                 all other live ranges then spill this */
-             if (willCS && sym->usl.spillLoc)
-               {
-
-                 symbol *leastUsed =
-                 leastUsedLR (liveRangesWith (spillable,
-                                              allLRs,
-                                              ebbs[i],
-                                              ic));
-                 if (leastUsed &&
-                     leastUsed->used > sym->used)
-                   {
-                     spillThis (sym);
-                     continue;
+               if (willCS) {
+                   if (sym->usl.spillLoc) {
+                       symbol *leastUsed = leastUsedLR (liveRangesWith (spillable,
+                                                                        allLRs, ebbs[i], ic));
+                       if (leastUsed && leastUsed->used > sym->used) {
+                           spillThis (sym);
+                           continue;
+                       }
+                   } else {
+                       /* if none of the liveRanges have a spillLocation then better
+                          to spill this one than anything else already assigned to registers */
+                       if (liveRangesWith(spillable,noSpilLoc,ebbs[i],ic)) {
+                           spillThis (sym);
+                           continue;
+                       }
                    }
                }