From patchwork Thu Aug 19 23:34:28 2010
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Subject: Combine four insns
Date: Thu, 19 Aug 2010 13:34:28 -0000
From: Bernd Schmidt <bernds@codesourcery.com>
X-Patchwork-Id: 62222
Message-Id: <4C6DBF84.2020702@codesourcery.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: Eric Botcazou <ebotcazou@adacore.com>, gcc-patches@gcc.gnu.org,
 Mark Mitchell <mark@codesourcery.com>,
 Richard Guenther <richard.guenther@gmail.com>,
 David Daney <ddaney@caviumnetworks.com>,
 Andi Kleen <andi@firstfloor.org>, Steven Bosscher <stevenb.gcc@gmail.com>

On 08/20/2010 12:53 AM, H.J. Lu wrote:
> This may have caused:
> 
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45350

Hmm.  FIND_REG_INC_NOTE expands to 0 on i686, so it didn't show up
there.  Anyway, both the set and the use are conditional on i1 != NULL,
so I've committed the following after a bootstrap.


Bernd


Index: ChangeLog
===================================================================
--- ChangeLog	(revision 163388)
+++ ChangeLog	(working copy)
@@ -1,3 +1,9 @@
+2010-08-19  Bernd Schmidt  <bernds@codesourcery.com>
+
+	PR bootstrap/45350
+	* combine.c (try_combine): Initialize i1_is_used and i2_is_used.  Fix
+	a comment.
+
 2010-08-19  Nathan Froyd  <froydnj@codesourcery.com>
 
 	* target.def (function_arg, function_incoming_arg): Remove const
Index: combine.c
===================================================================
--- combine.c	(revision 163383)
+++ combine.c	(working copy)
@@ -2511,7 +2511,7 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx
   /* Total number of SETs to put into I3.  */
   int total_sets;
   /* Nonzero if I2's or I1's body now appears in I3.  */
-  int i2_is_used, i1_is_used;
+  int i2_is_used = 0, i1_is_used = 0;
   /* INSN_CODEs for new I3, new I2, and user of condition code.  */
   int insn_code_number, i2_code_number = 0, other_code_number = 0;
   /* Contains I3 if the destination of I3 is used in its source, which means
@@ -2546,8 +2546,8 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx
   int i;
 
   /* Only try four-insn combinations when there's high likelihood of
-     success.  Look for simple insns, such as loads of constants, unary
-     operations, or binary operations involving a constant.  */
+     success.  Look for simple insns, such as loads of constants or
+     binary operations involving a constant.  */
   if (i0)
     {
       int i;