From 6867d9a9c5d90644fd0d1a20c802dc10cdd2c614 Mon Sep 17 00:00:00 2001
From: Tom de Vries <tom@codesourcery.com>
Date: Fri, 6 Jul 2012 11:22:06 +0000
Subject: [PATCH] re PR tree-optimization/51879 (Missed tail merging with
non-const/pure calls)
2012-07-06 Tom de Vries <tom@codesourcery.com>
PR tree-optimization/51879
* tree-ssa-sccvn.c (copy_reference_ops_from_call)
(visit_reference_op_call): Handle case that lhs is not an SSA_NAME.
(visit_use): Also call visit_reference_op_call for calls with a vdef.
From-SVN: r189323
---
gcc/ChangeLog | 7 +++++++
gcc/tree-ssa-sccvn.c | 42 +++++++++++++++++++++++++++++++-----------
2 files changed, 38 insertions(+), 11 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 12339ad08739..871e023603fa 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2012-07-06 Tom de Vries <tom@codesourcery.com>
+
+ PR tree-optimization/51879
+ * tree-ssa-sccvn.c (copy_reference_ops_from_call)
+ (visit_reference_op_call): Handle case that lhs is not an SSA_NAME.
+ (visit_use): Also call visit_reference_op_call for calls with a vdef.
+
2012-07-06 Tom de Vries <tom@codesourcery.com>
PR tree-optimization/52009
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index cd1acde49dfc..c1102a2c56e6 100644
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -946,6 +946,20 @@ copy_reference_ops_from_call (gimple call,
{
vn_reference_op_s temp;
unsigned i;
+ tree lhs = gimple_call_lhs (call);
+
+ /* If 2 calls have a different non-ssa lhs, vdef value numbers should be
+ different. By adding the lhs here in the vector, we ensure that the
+ hashcode is different, guaranteeing a different value number. */
+ if (lhs && TREE_CODE (lhs) != SSA_NAME)
+ {
+ memset (&temp, 0, sizeof (temp));
+ temp.opcode = MODIFY_EXPR;
+ temp.type = TREE_TYPE (lhs);
+ temp.op0 = lhs;
+ temp.off = -1;
+ VEC_safe_push (vn_reference_op_s, heap, *result, &temp);
+ }
/* Copy the type, opcode, function being called and static chain. */
memset (&temp, 0, sizeof (temp));
@@ -2633,6 +2647,10 @@ visit_reference_op_call (tree lhs, gimple stmt)
tree vuse = gimple_vuse (stmt);
tree vdef = gimple_vdef (stmt);
+ /* Non-ssa lhs is handled in copy_reference_ops_from_call. */
+ if (lhs && TREE_CODE (lhs) != SSA_NAME)
+ lhs = NULL_TREE;
+
vr1.vuse = vuse ? SSA_VAL (vuse) : NULL_TREE;
vr1.operands = valueize_shared_reference_ops_from_call (stmt);
vr1.type = gimple_expr_type (stmt);
@@ -3424,18 +3442,20 @@ visit_use (tree use)
}
}
- /* ??? We should handle stores from calls. */
if (!gimple_call_internal_p (stmt)
- && (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST)
- /* If the call has side effects, subsequent calls won't have
- the same incoming vuse, so it's save to assume
- equality. */
- || gimple_has_side_effects (stmt))
- && ((lhs && TREE_CODE (lhs) == SSA_NAME)
- || (!lhs && gimple_vdef (stmt))))
- {
- changed = visit_reference_op_call (lhs, stmt);
- }
+ && (/* Calls to the same function with the same vuse
+ and the same operands do not necessarily return the same
+ value, unless they're pure or const. */
+ gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST)
+ /* If calls have a vdef, subsequent calls won't have
+ the same incoming vuse. So, if 2 calls with vdef have the
+ same vuse, we know they're not subsequent.
+ We can value number 2 calls to the same function with the
+ same vuse and the same operands which are not subsequent
+ the same, because there is no code in the program that can
+ compare the 2 values. */
+ || gimple_vdef (stmt)))
+ changed = visit_reference_op_call (lhs, stmt);
else
changed = defs_to_varying (stmt);
}
--
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