@@ -1,3 +1,14 @@
+2015-10-29 Jeff Law <law@redhat.com>
+
+ * tree-ssa-scopedtables.h (const_and_copies): Remove invalidate
+ method.
+ * tree-ssa-scopedtables.h (const_and_copies::invalidate): Remove.
+ * tree-ssa-threadedge.c
+ (record_temporary_equivalences_from_stmts_at_dest): Remove
+ backedge_seen argument and associated code which invalidated
+ equivalences based on the value of that argument.
+ (thread_through_normal_block): Corresponding changes.
+
2015-10-29 Segher Boessenkool <segher@kernel.crashing.org>
* config/rs6000/rs6000.c (rs6000_reg_live_or_pic_offset_p): Move this
@@ -669,45 +669,6 @@ const_and_copies::record_const_or_copy (tree x, tree y, tree prev_x)
m_stack.quick_push (x);
}
-/* A new value has been assigned to LHS. If necessary, invalidate any
- equivalences that are no longer valid. This includes invaliding
- LHS and any objects that are currently equivalent to LHS.
-
- Finding the objects that are currently marked as equivalent to LHS
- is a bit tricky. We could walk the ssa names and see if any have
- SSA_NAME_VALUE that is the same as LHS. That's expensive.
-
- However, it's far more efficient to look at the unwinding stack as
- that will have all context sensitive equivalences which are the only
- ones that we really have to worry about here. */
-void
-const_and_copies::invalidate (tree lhs)
-{
-
- /* The stack is an unwinding stack. If the current element is NULL
- then it's a "stop unwinding" marker. Else the current marker is
- the SSA_NAME with an equivalence and the prior entry in the stack
- is what the current element is equivalent to. */
- for (int i = m_stack.length() - 1; i >= 0; i--)
- {
- /* Ignore the stop unwinding markers. */
- if ((m_stack)[i] == NULL)
- continue;
-
- /* We want to check the current value of stack[i] to see if
- it matches LHS. If so, then invalidate. */
- if (SSA_NAME_VALUE ((m_stack)[i]) == lhs)
- record_const_or_copy ((m_stack)[i], NULL_TREE);
-
- /* Remember, we're dealing with two elements in this case. */
- i--;
- }
-
- /* And invalidate any known value for LHS itself. */
- if (SSA_NAME_VALUE (lhs))
- record_const_or_copy (lhs, NULL_TREE);
-}
-
bool
expr_elt_hasher::equal (const value_type &p1, const compare_type &p2)
{
@@ -168,12 +168,6 @@ class const_and_copies
value for the first argument. Try to get rid of this in the future. */
void record_const_or_copy (tree, tree, tree);
- /* When threading we need to invalidate certain equivalences after
- following a loop backedge. The entries we need to invalidate will
- always be in this unwindable stack. This entry point handles
- finding and invalidating those entries. */
- void invalidate (tree);
-
private:
vec<tree> m_stack;
const_and_copies& operator= (const const_and_copies&);
@@ -215,8 +215,7 @@ static gimple *
record_temporary_equivalences_from_stmts_at_dest (edge e,
const_and_copies *const_and_copies,
avail_exprs_stack *avail_exprs_stack,
- pfn_simplify simplify,
- bool backedge_seen)
+ pfn_simplify simplify)
{
gimple *stmt = NULL;
gimple_stmt_iterator gsi;
@@ -268,22 +267,7 @@ record_temporary_equivalences_from_stmts_at_dest (edge e,
&& (gimple_code (stmt) != GIMPLE_CALL
|| gimple_call_lhs (stmt) == NULL_TREE
|| TREE_CODE (gimple_call_lhs (stmt)) != SSA_NAME))
- {
- /* STMT might still have DEFS and we need to invalidate any known
- equivalences for them.
-
- Consider if STMT is a GIMPLE_ASM with one or more outputs that
- feeds a conditional inside a loop. We might derive an equivalence
- due to the conditional. */
- tree op;
- ssa_op_iter iter;
-
- if (backedge_seen)
- FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_DEF)
- const_and_copies->invalidate (op);
-
- continue;
- }
+ continue;
/* The result of __builtin_object_size depends on all the arguments
of a phi node. Temporarily using only one edge produces invalid
@@ -316,14 +300,7 @@ record_temporary_equivalences_from_stmts_at_dest (edge e,
if (fndecl
&& (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_OBJECT_SIZE
|| DECL_FUNCTION_CODE (fndecl) == BUILT_IN_CONSTANT_P))
- {
- if (backedge_seen)
- {
- tree lhs = gimple_get_lhs (stmt);
- const_and_copies->invalidate (lhs);
- }
- continue;
- }
+ continue;
}
/* At this point we have a statement which assigns an RHS to an
@@ -389,19 +366,12 @@ record_temporary_equivalences_from_stmts_at_dest (edge e,
}
/* Record the context sensitive equivalence if we were able
- to simplify this statement.
-
- If we have traversed a backedge at some point during threading,
- then always enter something here. Either a real equivalence,
- or a NULL_TREE equivalence which is effectively invalidation of
- prior equivalences. */
+ to simplify this statement. */
if (cached_lhs
&& (TREE_CODE (cached_lhs) == SSA_NAME
|| is_gimple_min_invariant (cached_lhs)))
const_and_copies->record_const_or_copy (gimple_get_lhs (stmt),
cached_lhs);
- else if (backedge_seen)
- const_and_copies->invalidate (gimple_get_lhs (stmt));
}
return stmt;
}
@@ -925,8 +895,7 @@ thread_through_normal_block (edge e,
gimple *stmt
= record_temporary_equivalences_from_stmts_at_dest (e, const_and_copies,
avail_exprs_stack,
- simplify,
- *backedge_seen_p);
+ simplify);
/* There's two reasons STMT might be null, and distinguishing
between them is important.