function.c (fixup_var_refs_1): First try moving the expression directly into a register.

        * function.c (fixup_var_refs_1): First try moving the expression
        directly into a register.  Don't separate cc0 setter and user.

From-SVN: r25821

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1fa90c76a00fc274177b6ed7fdad9ce342027439..831320fa040c5e6e24ed56ff5ad7f729312ef201 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+Wed Mar 17 12:16:26 1999  Richard Henderson  <rth@cygnus.com>
+
+       * function.c (fixup_var_refs_1): First try moving the expression
+       directly into a register.  Don't separate cc0 setter and user.
+
 Wed Mar 17 11:20:29 1999  Dave Brolley  <brolley@cygnus.com>
 
        * cppfiles.c (PIPE_BUF): #define PIPE_BUF if not defined already.

diff --git a/gcc/function.c b/gcc/function.c
index d6d5aa6557fc20f52c2c77d37f3112762f42e5fc..82ad012e9f3337531d78a84834b7e978754c3902 100644 (file)
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -1995,18 +1995,45 @@ fixup_var_refs_1 (var, promoted_mode, loc, insn, replacements)
          /* Prevent sharing of rtl that might lose.  */
          rtx sub = copy_rtx (XEXP (var, 0));
 
-         start_sequence ();
-
          if (! validate_change (insn, loc, sub, 0))
            {
-             rtx y = force_operand (sub, NULL_RTX);
+             rtx y = gen_reg_rtx (GET_MODE (sub));
+             rtx seq, new_insn;
 
-             if (! validate_change (insn, loc, y, 0))
-               *loc = copy_to_reg (y);
-           }
+             /* We should be able to replace with a register or all is lost.
+                Note that we can't use validate_change to verify this, since
+                we're not caring for replacing all dups simultaneously.  */
+             if (! validate_replace_rtx (*loc, y, insn))
+               abort ();
 
-         emit_insn_before (gen_sequence (), insn);
-         end_sequence ();
+             /* Careful!  First try to recognize a direct move of the
+                value, mimicking how things are done in gen_reload wrt
+                PLUS.  Consider what happens when insn is a conditional
+                move instruction and addsi3 clobbers flags.  */
+
+             start_sequence ();
+             new_insn = emit_insn (gen_rtx_SET (VOIDmode, y, sub));
+             seq = gen_sequence ();
+             end_sequence ();
+
+             if (recog_memoized (new_insn) < 0)
+               {
+                 /* That failed.  Fall back on force_operand and hope.  */
+
+                 start_sequence ();
+                 force_operand (sub, y);
+                 seq = gen_sequence ();
+                 end_sequence ();
+               }
+
+#ifdef HAVE_cc0
+             /* Don't separate setter from user.  */
+             if (PREV_INSN (insn) && sets_cc0_p (PREV_INSN (insn)))
+               insn = PREV_INSN (insn);
+#endif
+
+             emit_insn_before (seq, insn);
+           }
        }
       return;