re PR rtl-optimization/43438 (possible wrong code bug)

2010-03-20  Richard Guenther  <rguenther@suse.de>

	PR rtl-optimization/43438
	* combine.c (make_extraction): Properly zero-/sign-extend an
	extraction of the low part of a CONST_INT.  Also handle
	CONST_DOUBLE.

	* gcc.c-torture/execute/pr43438.c: New testcase.

From-SVN: r157592

gcc/ChangeLog

+2010-03-20  Richard Guenther  <rguenther@suse.de>
+
+	PR rtl-optimization/43438
+	* combine.c (make_extraction): Properly zero-/sign-extend an
+	extraction of the low part of a CONST_INT.  Also handle
+	CONST_DOUBLE.
+
 2010-03-19  Mike Stump  <mikestump@comcast.net>
 
 	* config/i386/darwin.h (SUBTARGET32_DEFAULT_CPU): Add.

gcc/combine.c

@@ -6793,8 +6793,10 @@ make_extraction (enum machine_mode mode, rtx inner, HOST_WIDE_INT pos,
       if (mode == tmode)
 	return new_rtx;
 
-      if (CONST_INT_P (new_rtx))
-	return gen_int_mode (INTVAL (new_rtx), mode);
+      if (CONST_INT_P (new_rtx)
+	  || GET_CODE (new_rtx) == CONST_DOUBLE)
+	return simplify_unary_operation (unsignedp ? ZERO_EXTEND : SIGN_EXTEND,
+					 mode, new_rtx, tmode);
 
       /* If we know that no extraneous bits are set, and that the high
 	 bit is not set, convert the extraction to the cheaper of

gcc/testsuite/ChangeLog

+2010-03-20  Richard Guenther  <rguenther@suse.de>
+
+	PR rtl-optimization/43438
+	* gcc.c-torture/execute/pr43438.c: New testcase.
+
 2010-03-20  Dodji Seketeli  <dodji@redhat.com>
 
 	PR c++/43375

gcc/testsuite/gcc.c-torture/execute/pr43438.c

+extern void abort (void);
+
+static unsigned char g_2 = 1;
+static int g_9;
+static int *l_8 = &g_9;
+
+static void func_12(int p_13)
+{
+  int * l_17 = &g_9;
+  *l_17 &= 0 < p_13;
+}
+
+int main(void)
+{
+  unsigned char l_11 = 254;
+  *l_8 |= g_2;
+  l_11 |= *l_8;
+  func_12(l_11);
+  if (g_9 != 1)
+    abort ();
+  return 0;
+} 
+