re PR target/21297 (buf[i+i]=0 stores buf[i] when -O2)

	PR target/21297
	* config/i386/i386.c (legitimize_address): When canonicalizing
	ASHIFT into MULT, multiply by 1 << shift_count instead of
	1 << log2 (shift_count).

	* gcc.c-torture/execute/20050502-2.c: New test.

From-SVN: r99156

gcc/ChangeLog

+2005-05-03  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/21297
+	* config/i386/i386.c (legitimize_address): When canonicalizing
+	ASHIFT into MULT, multiply by 1 << shift_count instead of
+	1 << log2 (shift_count).
+
 2005-05-03  Andrew MacLeod  <amacleod@redhat.com>
 
 	* lambda-code.c (gcc_loop_to_lambda_loop, 

gcc/config/i386/i386.c

@@ -5902,9 +5902,10 @@ legitimize_address (rtx x, rtx oldx ATTRIBUTE_UNUSED, enum machine_mode mode)
   /* Canonicalize shifts by 0, 1, 2, 3 into multiply */
   if (GET_CODE (x) == ASHIFT
       && GET_CODE (XEXP (x, 1)) == CONST_INT
-      && (log = (unsigned) exact_log2 (INTVAL (XEXP (x, 1)))) < 4)
+      && (unsigned HOST_WIDE_INT) INTVAL (XEXP (x, 1)) < 4)
     {
       changed = 1;
+      log = INTVAL (XEXP (x, 1));
       x = gen_rtx_MULT (Pmode, force_reg (Pmode, XEXP (x, 0)),
 			GEN_INT (1 << log));
     }
@@ -5915,9 +5916,10 @@ legitimize_address (rtx x, rtx oldx ATTRIBUTE_UNUSED, enum machine_mode mode)
 
       if (GET_CODE (XEXP (x, 0)) == ASHIFT
 	  && GET_CODE (XEXP (XEXP (x, 0), 1)) == CONST_INT
-	  && (log = (unsigned) exact_log2 (INTVAL (XEXP (XEXP (x, 0), 1)))) < 4)
+	  && (unsigned HOST_WIDE_INT) INTVAL (XEXP (XEXP (x, 0), 1)) < 4)
 	{
 	  changed = 1;
+	  log = INTVAL (XEXP (XEXP (x, 0), 1));
 	  XEXP (x, 0) = gen_rtx_MULT (Pmode,
 				      force_reg (Pmode, XEXP (XEXP (x, 0), 0)),
 				      GEN_INT (1 << log));
@@ -5925,9 +5927,10 @@ legitimize_address (rtx x, rtx oldx ATTRIBUTE_UNUSED, enum machine_mode mode)
 
       if (GET_CODE (XEXP (x, 1)) == ASHIFT
 	  && GET_CODE (XEXP (XEXP (x, 1), 1)) == CONST_INT
-	  && (log = (unsigned) exact_log2 (INTVAL (XEXP (XEXP (x, 1), 1)))) < 4)
+	  && (unsigned HOST_WIDE_INT) INTVAL (XEXP (XEXP (x, 1), 1)) < 4)
 	{
 	  changed = 1;
+	  log = INTVAL (XEXP (XEXP (x, 1), 1));
 	  XEXP (x, 1) = gen_rtx_MULT (Pmode,
 				      force_reg (Pmode, XEXP (XEXP (x, 1), 0)),
 				      GEN_INT (1 << log));

gcc/testsuite/ChangeLog

+2005-05-03  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/21297
+	* gcc.c-torture/execute/20050502-2.c: New test.
+
 2005-05-03  Uros Bizjak  <uros@kss-loka.si>
 
 	PR middle-end/21282

gcc/testsuite/gcc.c-torture/execute/20050502-2.c

+/* PR target/21297 */
+typedef __SIZE_TYPE__ size_t;
+extern int memcmp (const char *, const char *, size_t);
+extern void abort ();
+
+void
+foo (char *x)
+{
+  int i;
+  for (i = 0; i < 2; i++);
+  x[i + i] = '\0';
+}
+
+void
+bar (char *x)
+{
+  int i;
+  for (i = 0; i < 2; i++);
+  x[i + i + i + i] = '\0';
+}
+
+int
+main (void)
+{
+  char x[] = "IJKLMNOPQR";
+  foo (x);
+  if (memcmp (x, "IJKL\0NOPQR", sizeof x) != 0)
+    abort ();
+  x[4] = 'M';
+  bar (x);
+  if (memcmp (x, "IJKLMNOP\0R", sizeof x) != 0)
+    abort ();
+  return 0;
+}