re PR rtl-optimization/13313 (Wrong code generated)

	PR optimization/13313
	* combine.c (make_extraction) [REG]: Do not use
	gen_lowpart_for_combine when POS is non-zero.

From-SVN: r74676

gcc/ChangeLog

+2003-12-16  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+	PR optimization/13313
+	* combine.c (make_extraction) [REG]: Do not use
+	gen_lowpart_for_combine when POS is non-zero.
+
 2003-12-16  Hartmut Penner  <hpenner@de.ibm.com>
 
 	* altivec.h (vec_cmple, vec_all_numeric): Fix typo.

gcc/combine.c

@@ -6043,10 +6043,11 @@ make_extraction (enum machine_mode mode, rtx inner, HOST_WIDE_INT pos,
 	{
 	  if (tmode != inner_mode)
 	    {
-	      if (in_dest)
+	      /* We can't call gen_lowpart_for_combine in a DEST since we
+		 always want a SUBREG (see below) and it would sometimes
+		 return a new hard register.  */
+	      if (pos || in_dest)
 		{
-		  /* We can't call gen_lowpart_for_combine here since we always want
-		     a SUBREG and it would sometimes return a new hard register.  */
 		  HOST_WIDE_INT final_word = pos / BITS_PER_WORD;
 
 		  if (WORDS_BIG_ENDIAN

gcc/testsuite/ChangeLog

+2003-12-16  Eric Botcazou  <ebotcazou@libertysurf.fr>
+
+	* gcc.c-torture/execute/20031216-1.c: New test.
+
 2003-12-16  Giovanni Bajo  <giovannibajo@gcc.gnu.org>
 
 	* g++.dg/template/ptrmem7.C: Simplified the test case to not hit
@@ -134,10 +138,10 @@
 	* g++.dg/ext/visibility-5.C: Likewise.
 	* g++.dg/ext/visibility-6.C: Likewise.
 
-2003-12-07  Giovanni Bajo  <giovannibajo@gcc.gnu.org>
-
-	* g++.dg/lookup/java1.C: New test.
-	* g++.dg/lookup/java2.C: New test.
+2003-12-07  Giovanni Bajo  <giovannibajo@gcc.gnu.org>
+
+	* g++.dg/lookup/java1.C: New test.
+	* g++.dg/lookup/java2.C: New test.
 
 2003-12-07  Falk Hueffner  <falk@debian.org>
 

gcc/testsuite/gcc.c-torture/execute/20031216-1.c

+/* PR optimization/13313 */
+/* Origin: Mike Lerwill <mike@ml-solutions.co.uk> */
+
+extern void abort(void);
+
+void DisplayNumber (unsigned long v)
+{
+  if (v != 0x9aL)
+    abort();
+}
+
+unsigned long ReadNumber (void)
+{
+  return 0x009a0000L;
+}
+
+int main (void)
+{
+  unsigned long tmp;
+  tmp = (ReadNumber() & 0x00ff0000L) >> 16;
+  DisplayNumber (tmp);
+  return 0;
+}