How does this look as a potential fix for PR64703? I haven't made
many forays into gimple code, so even though this patch passes
bootstrap and regression testing on powerpc64-linux it's quite
possible this is the wrong place to change. If it does look to be OK,
then I'll fill out the targetm changes, include a testcase etc.
PR target/64703
* tree-ssa-alias.c (pt_solution_includes_base): New function,
extracted from..
(ref_maybe_used_by_call_p_1): ..here. Delete dead code checking
for NULL return from ao_ref_base. Handle potential memory
reference by indirect calls on targets using function descriptors.
Index: gcc/tree-ssa-alias.c
===================================================================
--- gcc/tree-ssa-alias.c (revision 220025)
+++ gcc/tree-ssa-alias.c (working copy)
@@ -1532,6 +1532,23 @@ refs_output_dependent_p (tree store1, tree store2)
return refs_may_alias_p_1 (&r1, &r2, false);
}
+static bool
+pt_solution_includes_base (struct pt_solution *pt, tree base)
+{
+ if (DECL_P (base))
+ return pt_solution_includes (pt, base);
+
+ if ((TREE_CODE (base) == MEM_REF
+ || TREE_CODE (base) == TARGET_MEM_REF)
+ && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
+ {
+ struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
+ if (pi)
+ return pt_solutions_intersect (pt, &pi->pt);
+ }
+ return true;
+}
+
/* If the call CALL may use the memory reference REF return true,
otherwise return false. */
@@ -1542,15 +1559,24 @@ ref_maybe_used_by_call_p_1 (gcall *call, ao_ref *r
unsigned i;
int flags = gimple_call_flags (call);
+ base = ao_ref_base (ref);
+ callee = gimple_call_fn (call);
+ if (callee && TREE_CODE (callee) == SSA_NAME
+ /* && targetm.function_descriptors */)
+ {
+ /* Handle indirect call. When a target defines the address of a
+ function as that of a function descriptor, then dereferencing
+ a function pointer implicitly references memory. */
+ struct ptr_info_def *pi = SSA_NAME_PTR_INFO (callee);
+ if (pi && pt_solution_includes_base (&pi->pt, base))
+ return true;
+ }
+
/* Const functions without a static chain do not implicitly use memory. */
if (!gimple_call_chain (call)
&& (flags & (ECF_CONST|ECF_NOVOPS)))
goto process_args;
- base = ao_ref_base (ref);
- if (!base)
- return true;
-
/* A call that is not without side-effects might involve volatile
accesses and thus conflicts with all other volatile accesses. */
if (ref->volatile_p)
@@ -1564,7 +1590,7 @@ ref_maybe_used_by_call_p_1 (gcall *call, ao_ref *r
&& !is_global_var (base))
goto process_args;
- callee = gimple_call_fndecl (call);
+ callee = gimple_call_addr_fndecl (callee);
/* Handle those builtin functions explicitly that do not act as
escape points. See tree-ssa-structalias.c:find_func_aliases
@@ -1803,23 +1829,7 @@ ref_maybe_used_by_call_p_1 (gcall *call, ao_ref *r
}
/* Check if the base variable is call-used. */
- if (DECL_P (base))
- {
- if (pt_solution_includes (gimple_call_use_set (call), base))
- return true;
- }
- else if ((TREE_CODE (base) == MEM_REF
- || TREE_CODE (base) == TARGET_MEM_REF)
- && TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
- {
- struct ptr_info_def *pi = SSA_NAME_PTR_INFO (TREE_OPERAND (base, 0));
- if (!pi)
- return true;
-
- if (pt_solutions_intersect (gimple_call_use_set (call), &pi->pt))
- return true;
- }
- else
+ if (pt_solution_includes_base (gimple_call_use_set (call), base))
return true;
/* Inspect call arguments for passed-by-value aliases. */
--
Alan Modra
Australia Development Lab, IBM
