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| author | Richard Biener <rguenther@suse.de> | 2016-09-23 12:39:05 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2016-09-23 12:39:05 +0000 |
| commit | 113d06a486475c8c1682771a392fdb056685cf01 (patch) | |
| tree | 8cd4536059b68c50614d19104565da7dd6ac36c9 /gcc/tree-ssa-sccvn.c | |
| parent | 26bedff5fdfaf69b1e1d4a597e4a505d0d3dac87 (diff) | |
| download | gcc-113d06a486475c8c1682771a392fdb056685cf01.zip gcc-113d06a486475c8c1682771a392fdb056685cf01.tar.gz gcc-113d06a486475c8c1682771a392fdb056685cf01.tar.bz2 | |
tree-ssa-sccvn.c (visit_reference_op_call): Value number virtual definition to virtual use if...
2016-09-23 Richard Biener <rguenther@suse.de>
* tree-ssa-sccvn.c (visit_reference_op_call): Value number
virtual definition to virtual use if the call devirtualizes
to a const or pure function.
(visit_use): Also visit calls we can devirtualize to a
const or pure function.
* gcc.dg/tree-ssa/ssa-fre-56.c: New testcase.
From-SVN: r240431
Diffstat (limited to 'gcc/tree-ssa-sccvn.c')
| -rw-r--r-- | gcc/tree-ssa-sccvn.c | 33 |
1 files changed, 30 insertions, 3 deletions
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c index 21cc54e..7f44ec8 100644 --- a/gcc/tree-ssa-sccvn.c +++ b/gcc/tree-ssa-sccvn.c @@ -3484,8 +3484,24 @@ visit_reference_op_call (tree lhs, gcall *stmt) { vn_reference_t vr2; vn_reference_s **slot; + tree vdef_val = vdef; if (vdef) - changed |= set_ssa_val_to (vdef, vdef); + { + /* If we value numbered an indirect functions function to + one not clobbering memory value number its VDEF to its + VUSE. */ + tree fn = gimple_call_fn (stmt); + if (fn && TREE_CODE (fn) == SSA_NAME) + { + fn = SSA_VAL (fn); + if (TREE_CODE (fn) == ADDR_EXPR + && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL + && (flags_from_decl_or_type (TREE_OPERAND (fn, 0)) + & (ECF_CONST | ECF_PURE))) + vdef_val = vuse_ssa_val (gimple_vuse (stmt)); + } + changed |= set_ssa_val_to (vdef, vdef_val); + } if (lhs) changed |= set_ssa_val_to (lhs, lhs); vr2 = current_info->references_pool->allocate (); @@ -3498,7 +3514,7 @@ visit_reference_op_call (tree lhs, gcall *stmt) vr2->set = vr1.set; vr2->hashcode = vr1.hashcode; vr2->result = lhs; - vr2->result_vdef = vdef; + vr2->result_vdef = vdef_val; slot = current_info->references->find_slot_with_hash (vr2, vr2->hashcode, INSERT); gcc_assert (!*slot); @@ -3912,11 +3928,22 @@ visit_use (tree use) } } + /* Pick up flags from a devirtualization target. */ + tree fn = gimple_call_fn (stmt); + int extra_fnflags = 0; + if (fn && TREE_CODE (fn) == SSA_NAME) + { + fn = SSA_VAL (fn); + if (TREE_CODE (fn) == ADDR_EXPR + && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL) + extra_fnflags = flags_from_decl_or_type (TREE_OPERAND (fn, 0)); + } if (!gimple_call_internal_p (call_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 (call_stmt) & (ECF_PURE | ECF_CONST) + ((gimple_call_flags (call_stmt) | extra_fnflags) + & (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. |