(try_combine): Don't use split if dest of new I2 is used between I2

and I3.

From-SVN: r12293

diff --git a/gcc/combine.c b/gcc/combine.c
index 9427060d9c6bf3ac29c5cecde39acf6303cd6d33..3dbdb183e5dbc651303e5d264513e9fdd2278c2a 100644 (file)
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -1802,9 +1802,12 @@ try_combine (i3, i2, i1)
                                              &i2_scratches);
 
          /* If I2 or I3 has multiple SETs, we won't know how to track
-            register status, so don't use these insns.  */
+            register status, so don't use these insns.  If I2's destination
+            is used between I2 and I3, we also can't use these insns.  */
 
-         if (i2_code_number >= 0 && i2set && i3set)
+         if (i2_code_number >= 0 && i2set && i3set
+             && (next_real_insn (i2) == i3
+                 || ! reg_used_between_p (SET_DEST (i2set), i2, i3)))
            insn_code_number = recog_for_combine (&newi3pat, i3, &new_i3_notes,
                                                  &i3_scratches); 
          if (insn_code_number >= 0)