[PATCH, PR 51782] Derive rtx address space from base object

[Martin Jambor <mjambor at suse dot cz>]

Hi,

PR 51782 showed that COMPONENT_REFs created by SRA got expanded with a
wrong address space because the address space was not specified in the
type of the whole tree.  This is however inconsistent with how we
encode address spaces in MEM_REFs where they are supposed to be stored
in the type of its address operand (as opposed to the type of the
reference).  Therefore the following patch changes the expansion to
always look at the base address and look through MEM_REFs if
necessary.

It fixes the issue for me on a cross compiler, a bootstrap and
testsuite run on x86_64-linux showed only regressions described in PR
52297 so I consider it successful.  My understanding is that Richi
approved it in bugzilla.  Georg-Johann Lay said he would test it on HW
or simulator that actually uses address spaces and he has also already
committed a testcase for this bug.  Therefore I intend to commit the
patch if his tests pass too.

Thanks,

Martin


2012-02-20  Martin Jambor  <mjambor@suse.cz>

	PR tree-optimizaion/51782
	* emit-rtl.c (set_mem_attributes_minus_bitpos): Set address space
	according to the base object.

Index: src/gcc/emit-rtl.c
===================================================================
--- src.orig/gcc/emit-rtl.c	2012-02-13 14:52:28.000000000 +0100
+++ src/gcc/emit-rtl.c	2012-02-20 18:35:03.000000000 +0100
@@ -1548,6 +1548,7 @@ set_mem_attributes_minus_bitpos (rtx ref
   HOST_WIDE_INT apply_bitpos = 0;
   tree type;
   struct mem_attrs attrs, *defattrs, *refattrs;
+  addr_space_t as;
 
   /* It can happen that type_for_mode was given a mode for which there
      is no language-level type.  In which case it returns NULL, which
@@ -1681,17 +1682,29 @@ set_mem_attributes_minus_bitpos (rtx ref
       MEM_NOTRAP_P (ref) = !tree_could_trap_p (t);
 
       base = get_base_address (t);
-      if (base && DECL_P (base)
-	  && TREE_READONLY (base)
-	  && (TREE_STATIC (base) || DECL_EXTERNAL (base))
-	  && !TREE_THIS_VOLATILE (base))
-	MEM_READONLY_P (ref) = 1;
-
-      /* Mark static const strings readonly as well.  */
-      if (base && TREE_CODE (base) == STRING_CST
-	  && TREE_READONLY (base)
-	  && TREE_STATIC (base))
-	MEM_READONLY_P (ref) = 1;
+      if (base)
+	{
+	  if (DECL_P (base)
+	      && TREE_READONLY (base)
+	      && (TREE_STATIC (base) || DECL_EXTERNAL (base))
+	      && !TREE_THIS_VOLATILE (base))
+	    MEM_READONLY_P (ref) = 1;
+
+	  /* Mark static const strings readonly as well.  */
+	  if (TREE_CODE (base) == STRING_CST
+	      && TREE_READONLY (base)
+	      && TREE_STATIC (base))
+	    MEM_READONLY_P (ref) = 1;
+
+	  if (TREE_CODE (base) == MEM_REF
+	      || TREE_CODE (base) == TARGET_MEM_REF)
+	    as = TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (TREE_OPERAND (base,
+								      0))));
+	  else
+	    as = TYPE_ADDR_SPACE (TREE_TYPE (base));
+	}
+      else
+	as = TYPE_ADDR_SPACE (type);
 
       /* If this expression uses it's parent's alias set, mark it such
 	 that we won't change it.  */
@@ -1830,6 +1843,8 @@ set_mem_attributes_minus_bitpos (rtx ref
 	  attrs.align = MAX (attrs.align, obj_align);
 	}
     }
+  else
+    as = TYPE_ADDR_SPACE (type);
 
   /* If we modified OFFSET based on T, then subtract the outstanding
      bit position offset.  Similarly, increase the size of the accessed
@@ -1843,7 +1858,7 @@ set_mem_attributes_minus_bitpos (rtx ref
     }
 
   /* Now set the attributes we computed above.  */
-  attrs.addrspace = TYPE_ADDR_SPACE (type);
+  attrs.addrspace = as;
   set_mem_attrs (ref, &attrs);
 }