From: Jan Hubicka <jh@suse.cz>
Date: Tue, 19 Feb 2002 11:39:01 +0000 (+0100)
Subject: * regmove.c (regmove_optimize): Avoid increasing of register pressure.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=fd973d5630bb29a2a0a90aa325b26395b8882320;p=gcc.git

* regmove.c (regmove_optimize): Avoid increasing of register pressure.

From-SVN: r49864
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ffb087cf2fd..b6f6a1c1de0 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+Tue Feb 19 12:37:23 CET 2002  Jan Hubicka  <jh@suse.cz>
+
+	* regmove.c (regmove_optimize): Avoid increasing of register pressure.
+
 2002-02-19  Neil Booth  <neil@daikokuya.demon.co.uk>
 
 	PR other/5718
diff --git a/gcc/regmove.c b/gcc/regmove.c
index 9530128721a..aa1c17bbcee 100644
--- a/gcc/regmove.c
+++ b/gcc/regmove.c
@@ -1328,19 +1328,22 @@ regmove_optimize (f, nregs, regmove_dump_file)
 		}
 	      src_class = reg_preferred_class (REGNO (src));
 	      dst_class = reg_preferred_class (REGNO (dst));
-	      if (! regclass_compatible_p (src_class, dst_class))
+
+	      if (! (src_note = find_reg_note (insn, REG_DEAD, src)))
 		{
-		  if (!copy_src)
-		    {
-		      copy_src = src;
-		      copy_dst = dst;
-		    }
+		  /* We used to force the copy here like in other cases, but
+		     it produces worse code, as it eliminates no copy
+		     instructions and the copy emitted will be produced by
+		     reload anyway.  On patterns with multiple alternatives,
+		     there may be better sollution availble.
+
+		     In particular this change produced slower code for numeric
+		     i387 programs.  */
+
 		  continue;
 		}
 
-	      /* Can not modify an earlier insn to set dst if this insn
-		 uses an old value in the source.  */
-	      if (reg_overlap_mentioned_p (dst, SET_SRC (set)))
+	      if (! regclass_compatible_p (src_class, dst_class))
 		{
 		  if (!copy_src)
 		    {
@@ -1350,7 +1353,9 @@ regmove_optimize (f, nregs, regmove_dump_file)
 		  continue;
 		}
 
-	      if (! (src_note = find_reg_note (insn, REG_DEAD, src)))
+	      /* Can not modify an earlier insn to set dst if this insn
+		 uses an old value in the source.  */
+	      if (reg_overlap_mentioned_p (dst, SET_SRC (set)))
 		{
 		  if (!copy_src)
 		    {
@@ -1360,7 +1365,6 @@ regmove_optimize (f, nregs, regmove_dump_file)
 		  continue;
 		}
 
-
 	      /* If src is set once in a different basic block,
 		 and is set equal to a constant, then do not use
 		 it for this optimization, as this would make it