From: Aldy Hernandez <aldyh@redhat.com>
Date: Tue, 25 Jul 2023 16:25:30 +0000 (-0400)
Subject: Initialize value in bit_value_unop.
X-Git-Tag: basepoints/gcc-15~7363
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7a48d8d28cc683974057ce9fdfd3fb224ff76641;p=thirdparty%2Fgcc.git

Initialize value in bit_value_unop.

bit_value_binop initializes VAL regardless of the final mask.  It even
has a comment to that effect:

  /* Ensure that VAL is initialized (to any value).  */

However, bit_value_unop, which in theory shares the same API, does not.
This causes range-ops to choke on uninitialized VALs for some inputs to
ABS.

Instead of fixing the callers, it's cleaner to make bit_value_unop and
bit_value_binop consistent.

gcc/ChangeLog:

	* tree-ssa-ccp.cc (bit_value_unop): Initialize val when appropriate.
---

diff --git a/gcc/tree-ssa-ccp.cc b/gcc/tree-ssa-ccp.cc
index 73fb7c11c643..15e65f160084 100644
--- a/gcc/tree-ssa-ccp.cc
+++ b/gcc/tree-ssa-ccp.cc
@@ -1359,7 +1359,10 @@ bit_value_unop (enum tree_code code, signop type_sgn, int type_precision,
     case ABS_EXPR:
     case ABSU_EXPR:
       if (wi::sext (rmask, rtype_precision) == -1)
-	*mask = -1;
+	{
+	  *mask = -1;
+	  *val = 0;
+	}
       else if (wi::neg_p (rmask))
 	{
 	  /* Result is either rval or -rval.  */
@@ -1385,6 +1388,7 @@ bit_value_unop (enum tree_code code, signop type_sgn, int type_precision,
 
     default:
       *mask = -1;
+      *val = 0;
       break;
     }
 }