[Bug target/30961] [4.2/4.3 regression] redundant reg/mem stores/moves

[hjl at lucon dot org]

------- Comment #12 from hjl at lucon dot org  2007-05-13 06:36 -------
find_reg computes the cost of moving to target register too high. This kludge
adjusts the cost of moving to target register and seems to work for the
testcase:

--- gcc/reload1.c.sse   2007-04-27 05:46:12.000000000 -0700
+++ gcc/reload1.c       2007-05-12 22:30:58.000000000 -0700
@@ -1723,6 +1723,20 @@ find_reg (struct insn_chain *chain, int
   HARD_REG_SET not_usable;
   HARD_REG_SET used_by_other_reload;
   reg_set_iterator rsi;
+  rtx body = PATTERN (chain->insn);
+  unsigned int dest_reg;
+
+  if (GET_CODE (body) == SET)
+    {
+      rtx dest = SET_DEST (body);
+
+      if ((REG_P (dest)
+          || (GET_CODE (dest) == SUBREG
+              && REG_P (SUBREG_REG (dest)))))
+       dest_reg = reg_or_subregno (dest);
+    }
+  else
+    dest_reg = FIRST_PSEUDO_REGISTER;

   COPY_HARD_REG_SET (not_usable, bad_spill_regs);
   IOR_HARD_REG_SET (not_usable, bad_spill_regs_global);
@@ -1746,7 +1760,7 @@ find_reg (struct insn_chain *chain, int
          && ! TEST_HARD_REG_BIT (used_by_other_reload, regno)
          && HARD_REGNO_MODE_OK (regno, rl->mode))
        {
-         int this_cost = spill_cost[regno];
+         int this_cost = dest_reg == regno ? 0 : spill_cost[regno];
          int ok = 1;
          unsigned int this_nregs = hard_regno_nregs[regno][rl->mode];


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30961