[backport gcc-4.8/trunk r186351 <mikpe@it.uu.se>]

gcc/

2012-04-11  H.J. Lu  <hongjiu.lu@intel.com>

	PR rtl-optimization/52876
	* emit-rtl.c (set_reg_attrs_from_value): Handle arbitrary value.
	Don't call mark_reg_pointer for incompatible pointer sign
	extension.

	* reginfo.c (reg_scan_mark_refs): Call set_reg_attrs_from_value 
	directly.

gcc/testsuite/

2012-04-11  H.J. Lu  <hongjiu.lu@intel.com>

	PR rtl-optimization/52876
	* gcc.target/i386/pr52876.c: New.

--- gcc-4.7.2/gcc/emit-rtl.c.~1~	2012-02-22 11:37:03.000000000 +0100
+++ gcc-4.7.2/gcc/emit-rtl.c	2013-02-10 14:16:47.103130184 +0100
@@ -964,6 +964,22 @@ void
 set_reg_attrs_from_value (rtx reg, rtx x)
 {
   int offset;
+  bool can_be_reg_pointer = true;
+
+  /* Don't call mark_reg_pointer for incompatible pointer sign
+     extension.  */
+  while (GET_CODE (x) == SIGN_EXTEND
+	 || GET_CODE (x) == ZERO_EXTEND
+	 || GET_CODE (x) == TRUNCATE
+	 || (GET_CODE (x) == SUBREG && subreg_lowpart_p (x)))
+    {
+#if defined(POINTERS_EXTEND_UNSIGNED) && !defined(HAVE_ptr_extend)
+      if ((GET_CODE (x) == SIGN_EXTEND && POINTERS_EXTEND_UNSIGNED)
+	  || (GET_CODE (x) != SIGN_EXTEND && ! POINTERS_EXTEND_UNSIGNED))
+	can_be_reg_pointer = false;
+#endif
+      x = XEXP (x, 0);
+    }
 
   /* Hard registers can be reused for multiple purposes within the same
      function, so setting REG_ATTRS, REG_POINTER and REG_POINTER_ALIGN
@@ -977,14 +993,14 @@ set_reg_attrs_from_value (rtx reg, rtx x
       if (MEM_OFFSET_KNOWN_P (x))
 	REG_ATTRS (reg) = get_reg_attrs (MEM_EXPR (x),
 					 MEM_OFFSET (x) + offset);
-      if (MEM_POINTER (x))
+      if (can_be_reg_pointer && MEM_POINTER (x))
 	mark_reg_pointer (reg, 0);
     }
   else if (REG_P (x))
     {
       if (REG_ATTRS (x))
 	update_reg_offset (reg, x, offset);
-      if (REG_POINTER (x))
+      if (can_be_reg_pointer && REG_POINTER (x))
 	mark_reg_pointer (reg, REGNO_POINTER_ALIGN (REGNO (x)));
     }
 }
--- gcc-4.7.2/gcc/reginfo.c.~1~	2012-01-31 20:11:00.000000000 +0100
+++ gcc-4.7.2/gcc/reginfo.c	2013-02-10 14:16:47.103130184 +0100
@@ -1222,17 +1222,7 @@ reg_scan_mark_refs (rtx x, rtx insn)
       /* If this is setting a register from a register or from a simple
 	 conversion of a register, propagate REG_EXPR.  */
       if (REG_P (dest) && !REG_ATTRS (dest))
-	{
-	  rtx src = SET_SRC (x);
-
-	  while (GET_CODE (src) == SIGN_EXTEND
-		 || GET_CODE (src) == ZERO_EXTEND
-		 || GET_CODE (src) == TRUNCATE
-		 || (GET_CODE (src) == SUBREG && subreg_lowpart_p (src)))
-	    src = XEXP (src, 0);
-
-	  set_reg_attrs_from_value (dest, src);
-	}
+	set_reg_attrs_from_value (dest, SET_SRC (x));
 
       /* ... fall through ...  */
 
--- gcc-4.7.2/gcc/testsuite/gcc.target/i386/pr52876.c.~1~	1970-01-01 01:00:00.000000000 +0100
+++ gcc-4.7.2/gcc/testsuite/gcc.target/i386/pr52876.c	2013-02-10 14:16:47.103130184 +0100
@@ -0,0 +1,25 @@
+/* { dg-do run { target { x32 } } } */
+/* { dg-options "-O2 -mx32 -maddress-mode=long" } */
+
+extern void abort (void);
+
+long long li;
+
+long long 
+__attribute__ ((noinline))
+testfunc (void* addr)
+{
+  li = (long long)(int)addr;
+  li &= 0xffffffff;
+  return li;
+}
+
+int main (void)
+{
+  volatile long long rv_test;
+  rv_test = testfunc((void*)0x87651234);
+  if (rv_test != 0x87651234ULL)
+    abort ();
+
+  return 0;
+}