The following attempts to set a MEM_BASE from set_mem_attributes_minus_bitpos
which is often first called on the expanded base of a complicated memory
reference. For now simply preserve a SYMBOL_REF (fancy unwrapping to be
implemented).
The commented code would transfer some points-to info.
* emit-rtl.cc (set_mem_attributes_minus_bitpos): If ref
is suitable as base, record it.
---
gcc/emit-rtl.cc | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/gcc/emit-rtl.cc b/gcc/emit-rtl.cc
index 1cf238d9571..3fb52a87e08 100644
--- a/gcc/emit-rtl.cc
+++ b/gcc/emit-rtl.cc
@@ -2027,6 +2027,12 @@ set_mem_attributes_minus_bitpos (rtx ref, tree t, int
objectp,
if (objectp || TREE_CODE (t) == INDIRECT_REF)
attrs.align = MAX (attrs.align, TYPE_ALIGN (type));
+ /* We usually expand the base of a complicated ref first, so record any
+ base value we can determine. ??? Probably should use a simplified
+ find_base_value here to unwrap a contained SYMBOL_REF. */
+ if (GET_CODE (ref) == SYMBOL_REF)
+ attrs.base = copy_rtx (ref);
+
/* If the size is known, we can set that. */
tree new_size = TYPE_SIZE_UNIT (type);
@@ -2074,6 +2080,24 @@ set_mem_attributes_minus_bitpos (rtx ref, tree t, int
objectp,
0))));
else
as = TYPE_ADDR_SPACE (TREE_TYPE (base));
+
+#if 0
+ /* Set the base RTX based on points-to info. */
+ if (!attrs.base
+ && (TREE_CODE (base) == MEM_REF
+ || TREE_CODE (base) == TARGET_MEM_REF)
+ && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME
+ && SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0)))
+ {
+ auto pt = &SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0))->pt;
+ if (pt->nonlocal
+ && !pt->anything
+ && !pt->escaped
+ && !pt->ipa_escaped
+ && bitmap_empty_p (pt->vars))
+ attrs.base = arg_base_value;
+ }
+#endif
}
/* If this expression uses it's parent's alias set, mark it such
--
2.35.3
