===================================================================
@@ -158,6 +158,7 @@ static tree decl_for_component_ref (tree
static int write_dependence_p (const_rtx,
const_rtx, machine_mode, rtx,
bool, bool, bool);
+static int compare_base_symbol_refs (const_rtx, const_rtx);
static void memory_modified_1 (rtx, const_rtx, void *);
@@ -1756,15 +1757,7 @@ rtx_equal_for_memref_p (const_rtx x, con
return LABEL_REF_LABEL (x) == LABEL_REF_LABEL (y);
case SYMBOL_REF:
- {
- tree x_decl = SYMBOL_REF_DECL (x);
- tree y_decl = SYMBOL_REF_DECL (y);
-
- if (!x_decl || !y_decl)
- return XSTR (x, 0) == XSTR (y, 0);
- else
- return compare_base_decls (x_decl, y_decl) == 1;
- }
+ return compare_base_symbol_refs (x, y) == 1;
case ENTRY_VALUE:
/* This is magic, don't go through canonicalization et al. */
@@ -2056,6 +2049,66 @@ compare_base_decls (tree base1, tree bas
return ret;
}
+/* Same as compare_base_decls but for SYMBOL_REF. */
+
+static int
+compare_base_symbol_refs (const_rtx x_base, const_rtx y_base)
+{
+ tree x_decl = SYMBOL_REF_DECL (x_base);
+ tree y_decl = SYMBOL_REF_DECL (y_base);
+ bool binds_def = true;
+
+ if (x_decl && y_decl)
+ return compare_base_decls (x_decl, y_decl);
+ if (x_decl || y_decl)
+ {
+ if (!x_decl)
+ {
+ std::swap (x_decl, y_decl);
+ std::swap (x_base, y_base);
+ }
+ /* We handle specially only section anchors and assume that other
+ labels may overlap with user variables in an arbitrary way. */
+ if (!SYMBOL_REF_HAS_BLOCK_INFO_P (y_base))
+ return -1;
+ /* Anchors contains static VAR_DECLs and CONST_DECLs. We are safe
+ to ignore CONST_DECLs because they are readonly. */
+ if (TREE_CODE (x_decl) != VAR_DECL
+ || (!TREE_STATIC (x_decl) && !TREE_PUBLIC (x_decl)))
+ return 0;
+
+ symtab_node *x_node = symtab_node::get_create (x_decl)
+ ->ultimate_alias_target ();
+ /* External variable can not be in section anchor. */
+ if (!x_node->definition)
+ return false;
+ x_base = XEXP (DECL_RTL (x_node->decl), 0);
+ /* If not in anchor, we can disambiguate. */
+ if (!SYMBOL_REF_HAS_BLOCK_INFO_P (x_base))
+ return false;
+
+ /* We have an alias of anchored variable. If it can be interposed;
+ we must assume it may or may not alias its anchor. */
+ binds_def = decl_binds_to_current_def_p (x_decl);
+ }
+ /* If we have variable in section anchor, we can compare by offset. */
+ if (SYMBOL_REF_HAS_BLOCK_INFO_P (x_base)
+ && SYMBOL_REF_HAS_BLOCK_INFO_P (y_base))
+ {
+ if (SYMBOL_REF_BLOCK (x_base) != SYMBOL_REF_BLOCK (y_base))
+ return 0;
+ if (SYMBOL_REF_BLOCK_OFFSET (x_base) == SYMBOL_REF_BLOCK_OFFSET (y_base))
+ return binds_def ? 1 : -1;
+ /* Mixing anchors and non-anchors may result to false negative.
+ We probably never do that. */
+ gcc_assert (SYMBOL_REF_ANCHOR_P (x_base) == SYMBOL_REF_ANCHOR_P (y_base));
+ return 0;
+ }
+ /* In general we assume that memory locations pointed to by different labels
+ may overlap in undefined ways. */
+ return XSTR (x_base, 0) == XSTR (y_base, 0) ? 1 : -1;
+}
+
/* Return 0 if the addresses X and Y are known to point to different
objects, 1 if they might be pointers to the same object. */
@@ -2111,18 +2164,10 @@ base_alias_check (rtx x, rtx x_base, rtx
|| (int) GET_MODE_UNIT_SIZE (x_mode) < -INTVAL (XEXP (y, 1))))
return 1;
+ /* Differing symbols not accessed via AND never alias. */
if (GET_CODE (x_base) == SYMBOL_REF && GET_CODE (y_base) == SYMBOL_REF)
- {
- tree x_decl = SYMBOL_REF_DECL (x_base);
- tree y_decl = SYMBOL_REF_DECL (y_base);
-
- /* We can assume that no stores are made to labels. */
- if (!x_decl || !y_decl)
- return 0;
- return compare_base_decls (x_decl, y_decl) != 0;
- }
+ return compare_base_symbol_refs (x_base, y_base) != 0;
- /* Differing symbols not accessed via AND never alias. */
if (GET_CODE (x_base) != ADDRESS && GET_CODE (y_base) != ADDRESS)
return 0;
@@ -2327,19 +2372,7 @@ memrefs_conflict_p (int xsize, rtx x, in
if (GET_CODE (x) == SYMBOL_REF && GET_CODE (y) == SYMBOL_REF)
{
- tree x_decl = SYMBOL_REF_DECL (x);
- tree y_decl = SYMBOL_REF_DECL (y);
- int cmp;
-
- if (!x_decl || !y_decl)
- {
- /* Label and normal symbol are never the same. */
- if (x_decl != y_decl)
- return 0;
- return offset_overlap_p (c, xsize, ysize);
- }
- else
- cmp = compare_base_decls (x_decl, y_decl);
+ int cmp = compare_base_symbol_refs (x,y);
/* If both decls are the same, decide by offsets. */
if (cmp == 1)