Ignore no-ops in cprop pass.

From-SVN: r28901

Ignore no-ops in cprop pass.
From-SVN: r28901
21e3a717 · Bernd Schmidt · Bernd Schmidt · 49b1e9eb · 21e3a717 · 21e3a717
Commit 21e3a717 authored Aug 26, 1999 by Bernd Schmidt Committed by Bernd Schmidt Aug 26, 1999
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gcc/ChangeLog
+4 -0

gcc/gcse.c
+5 -1

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--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
+Thu Aug 26 18:32:32 1999  Bernd Schmidt  <bernds@cygnus.co.uk>
+
+	* gcse.c (hash_scan_insn): Don't scan obvious no-ops.
+
 1999-08-26 09:42 -0700  Zack Weinberg  <zack@bitmover.com>

 	* tree.h: fancy_abort always takes three args.

--- a/gcc/gcse.c
+++ b/gcc/gcse.c
@@ -1919,7 +1919,11 @@ hash_scan_insn (insn, set_p, in_libcall_block)
     what's been modified.  */

  if (GET_CODE (pat) == SET && ! in_libcall_block)
-    hash_scan_set (pat, insn, set_p);
+    {
+      /* Ignore obvious no-ops.  */
+      if (SET_SRC (pat) != SET_DEST (pat))
+	hash_scan_set (pat, insn, set_p);
+    }
  else if (GET_CODE (pat) == PARALLEL)
    {
      int i;