Fix code that substitutes reloadreg into SET_DEST of previous insn.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@37711 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 031d454..2c12a96 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,9 @@
 2000-11-24  Bernd Schmidt  <bernds@redhat.co.uk>
 
+       * reload1.c (conflicts_with_override): New function.
+       (emit_input_reload_insns): Use it to tighten test for validity
+       of substituting into output of previous insn.
+
        * haifa-sched.c (struct ready_list): New.
        (ready_lastpos, ready_add, ready_remove_first, ready_sort): New static
        functions.

diff --git a/gcc/reload1.c b/gcc/reload1.c
index 926d796..60eac68 100644 (file)
--- a/gcc/reload1.c
+++ b/gcc/reload1.c
@@ -417,6 +417,7 @@ static int reload_reg_reaches_end_p PARAMS ((unsigned int, int,
                                                 enum reload_type));
 static int allocate_reload_reg         PARAMS ((struct insn_chain *, int,
                                                 int));
+static int conflicts_with_override     PARAMS ((rtx));
 static void failed_reload              PARAMS ((rtx, int));
 static int set_reload_reg              PARAMS ((int, int));
 static void choose_reload_regs_init    PARAMS ((struct insn_chain *, rtx *));
@@ -4882,6 +4883,21 @@ reload_reg_free_for_value_p (regno, opnum, type, value, out, reloadnum,
   return 1;
 }
 
+/* Determine whether the reload reg X overlaps any rtx'es used for
+   overriding inheritance.  Return nonzero if so.  */
+
+static int
+conflicts_with_override (x)
+     rtx x;
+{
+  int i;
+  for (i = 0; i < n_reloads; i++)
+    if (reload_override_in[i]
+       && reg_overlap_mentioned_p (x, reload_override_in[i]))
+      return 1;
+  return 0;
+}
+\f
 /* Give an error message saying we failed to find a reload for INSN,
    and clear out reload R.  */
 static void
@@ -6215,6 +6231,7 @@ emit_input_reload_insns (chain, rl, old, j)
           && dead_or_set_p (insn, old)
           /* This is unsafe if some other reload
              uses the same reg first.  */
+          && ! conflicts_with_override (reloadreg)
           && reload_reg_free_for_value_p (REGNO (reloadreg),
                                           rl->opnum,
                                           rl->when_needed,