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

4 files changed, 41 insertions, 7 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 45e05a8..733c289f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+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.
diff --git a/gcc/combine.c b/gcc/combine.c
index 02a92c1..2c92d24 100644
--- a/gcc/combine.c
+++ b/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
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6e1f126..3dd3a02 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+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>
 
diff --git a/gcc/testsuite/gcc.c-torture/execute/20031216-1.c b/gcc/testsuite/gcc.c-torture/execute/20031216-1.c
new file mode 100644
index 0000000..709f016
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/20031216-1.c
@@ -0,0 +1,23 @@
+/* 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;
+}