mmix.md ("negdf2"): Rewrite.

	* config/mmix/mmix.md ("negdf2"): Rewrite.
	("*expanded_negdf2"): New.

From-SVN: r57332

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0b22646..2496779 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2002-09-20  Hans-Peter Nilsson  <hp@bitrange.com>
+
+       * config/mmix/mmix.md ("negdf2"): Rewrite.
+       ("*expanded_negdf2"): New.
+
 2002-09-19  Jim Wilson  <wilson@redhat.com>
 
        * combine.c (simplify_set): When optimizing a subreg src with a

diff --git a/gcc/config/mmix/mmix.md b/gcc/config/mmix/mmix.md
index 0f36872..d234d8c 100644 (file)
--- a/gcc/config/mmix/mmix.md
+++ b/gcc/config/mmix/mmix.md
@@ -348,13 +348,22 @@ DIVU %1,%1,%2\;GET %0,:rR\;NEGU %2,0,%0\;CSNN %0,$255,%2")
   ""
   "NEGU %0,0,%1")
 
-;; FIXME: GCC should be able to synthesize this by itself as "0.0 - x".
 (define_expand "negdf2"
+  [(parallel [(set (match_operand:DF 0 "register_operand" "=r")
+                   (neg:DF (match_operand:DF 1 "register_operand" "r")))
+              (use (match_dup 2))])]
+  ""
+{
+  /* Emit bit-flipping sequence to be IEEE-safe wrt. -+0.  */
+  operands[2] = force_reg (DImode, GEN_INT ((HOST_WIDE_INT) 1 << 63));
+})
+
+(define_insn "*expanded_negdf2"
   [(set (match_operand:DF 0 "register_operand" "=r")
-       (minus:DF (match_dup 2)
-               (match_operand:DF 1 "register_operand" "r")))]
+        (neg:DF (match_operand:DF 1 "register_operand" "r")))
+   (use (match_operand:DI 2 "register_operand" "r"))]
   ""
-  "operands[2] = force_reg (DFmode, CONST0_RTX (DFmode));")
+  "XOR %0,%1,%2")
 
 ;; FIXME: define_expand for absdi2?