Don't return identity for CONST or symbolic reference

gcc/

	PR rtl-optimization/54157
	* combine.c (gen_lowpart_for_combine): Don't return identity
	for CONST or symbolic reference.

gcc/testsuite/

	PR rtl-optimization/54157
	* gcc.target/i386/pr54157.c: New file.

From-SVN: r190228

gcc/ChangeLog

+2012-08-08  Richard Sandiford  <rdsandiford@googlemail.com>
+	    H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR rtl-optimization/54157
+	* combine.c (gen_lowpart_for_combine): Don't return identity
+	for CONST or symbolic reference.
+
 2012-08-08 Michael Zolotukhin <michael.v.zolotukhin@intel.com>
 
 	* common/config/i386/i386-common.c (OPTION_MASK_ISA_ADX_SET): New.

gcc/combine.c

@@ -10634,13 +10634,6 @@ gen_lowpart_for_combine (enum machine_mode omode, rtx x)
   if (omode == imode)
     return x;
 
-  /* Return identity if this is a CONST or symbolic reference.  */
-  if (omode == Pmode
-      && (GET_CODE (x) == CONST
-	  || GET_CODE (x) == SYMBOL_REF
-	  || GET_CODE (x) == LABEL_REF))
-    return x;
-
   /* We can only support MODE being wider than a word if X is a
      constant integer or has a mode the same size.  */
   if (GET_MODE_SIZE (omode) > UNITS_PER_WORD

gcc/testsuite/ChangeLog

+2012-08-08  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR rtl-optimization/54157
+	* gcc.target/i386/pr54157.c: New file.
+
 2012-08-08 Michael Zolotukhin <michael.v.zolotukhin@intel.com>
 
 	* gcc.target/i386/adx-addcarryx32-1.c: New.

gcc/testsuite/gcc.target/i386/pr54157.c

+/* { dg-do compile { target { ! { ia32 } } } } */
+/* { dg-options "-O2 -mx32 -maddress-mode=long -ftree-vectorize" } */
+
+struct s2{
+  int n[24 -1][24 -1][24 -1];
+};
+
+struct test2{
+  struct s2 e;
+};
+
+struct test2 tmp2[4];
+
+void main1 ()
+{
+  int i,j;
+
+  for (i = 0; i < 24 -4; i++)
+      for (j = 0; j < 24 -4; j++)
+          tmp2[2].e.n[1][i][j] = 8;
+}