(try_combine): Restrict combining on CALL_INSNs.

(distribute_{notes,links}): Look at CALL_INSN_FUNCTION_USAGE.

From-SVN: r7236

diff --git a/gcc/combine.c b/gcc/combine.c
index 9f9133111314af3bb1c50832d93027b05b4a06d1..c9a0b3bcd24954656486579e734d08b15ebb5352 100644 (file)
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -1218,6 +1218,17 @@ try_combine (i3, i2, i1)
       || find_reg_note (i3, REG_LIBCALL, NULL_RTX))
     return 0;
 
+  /* If I1 or I2 is an argument set insn, and I3 is the actual
+     CALL_INSN using it as argument, never combine the two.
+     This to prevent the elimination of insns that setup a
+     parameter register for a CALL_INSN.  */
+  if (GET_CODE (i3) == CALL_INSN
+      && (((temp = single_set (i2))
+            && find_reg_fusage (i3, USE, SET_DEST (temp)))
+         || (i1 && (temp = single_set (i1))
+              && find_reg_fusage (i3, USE, SET_DEST (temp)))))
+    return 0;
+
   combine_attempts++;
 
   undobuf.num_undo = previous_num_undos = 0;
@@ -10423,7 +10434,11 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1)
             In both cases, we must search to see if we can find a previous
             use of A and put the death note there.  */
 
-         if (reg_referenced_p (XEXP (note, 0), PATTERN (i3)))
+         if (from_insn
+             && GET_CODE (from_insn) == CALL_INSN
+              && find_reg_fusage (from_insn, USE, XEXP (note, 0)))
+           place = from_insn;
+         else if (reg_referenced_p (XEXP (note, 0), PATTERN (i3)))
            place = i3;
          else if (i2 != 0 && next_nonnote_insn (i2) == i3
                   && reg_referenced_p (XEXP (note, 0), PATTERN (i2)))
@@ -10697,6 +10712,12 @@ distribute_links (links)
              place = insn;
            break;
          }
+       else if (GET_CODE (insn) == CALL_INSN
+             && find_reg_fusage (insn, USE, reg))
+         {
+           place = insn;
+           break;
+         }
 
       /* If we found a place to put the link, place it there unless there
         is already a link to the same insn as LINK at that point.  */