diff options
Diffstat (limited to 'gcc/tree-ssa-loop-im.c')
| -rw-r--r-- | gcc/tree-ssa-loop-im.c | 39 |
1 files changed, 34 insertions, 5 deletions
diff --git a/gcc/tree-ssa-loop-im.c b/gcc/tree-ssa-loop-im.c index 65c0b0d0b6f..eecb6206f45 100644 --- a/gcc/tree-ssa-loop-im.c +++ b/gcc/tree-ssa-loop-im.c @@ -1887,16 +1887,22 @@ hoist_memory_references (struct loop *loop, bitmap mem_refs, } } -/* Returns true if REF is always accessed in LOOP. */ +/* Returns true if REF is always accessed in LOOP. If STORED_P is true + make sure REF is always stored to in LOOP. */ static bool -ref_always_accessed_p (struct loop *loop, mem_ref_p ref) +ref_always_accessed_p (struct loop *loop, mem_ref_p ref, bool stored_p) { VEC (mem_ref_loc_p, heap) *locs = NULL; unsigned i; mem_ref_loc_p loc; bool ret = false; struct loop *must_exec; + tree base; + + base = get_base_address (ref->mem); + if (INDIRECT_REF_P (base)) + base = TREE_OPERAND (base, 0); get_all_locs_in_loop (loop, ref, &locs); for (i = 0; VEC_iterate (mem_ref_loc_p, locs, i, loc); i++) @@ -1904,6 +1910,22 @@ ref_always_accessed_p (struct loop *loop, mem_ref_p ref) if (!get_lim_data (loc->stmt)) continue; + /* If we require an always executed store make sure the statement + stores to the reference. */ + if (stored_p) + { + tree lhs; + if (!gimple_get_lhs (loc->stmt)) + continue; + lhs = get_base_address (gimple_get_lhs (loc->stmt)); + if (!lhs) + continue; + if (INDIRECT_REF_P (lhs)) + lhs = TREE_OPERAND (lhs, 0); + if (lhs != base) + continue; + } + must_exec = get_lim_data (loc->stmt)->always_executed_in; if (!must_exec) continue; @@ -2041,6 +2063,8 @@ ref_indep_loop_p (struct loop *loop, mem_ref_p ref) static bool can_sm_ref_p (struct loop *loop, mem_ref_p ref) { + tree base; + /* Unless the reference is stored in the loop, there is nothing to do. */ if (!bitmap_bit_p (ref->stored, loop->num)) return false; @@ -2051,9 +2075,14 @@ can_sm_ref_p (struct loop *loop, mem_ref_p ref) || !for_each_index (&ref->mem, may_move_till, loop)) return false; - /* If it can trap, it must be always executed in LOOP. */ - if (tree_could_trap_p (ref->mem) - && !ref_always_accessed_p (loop, ref)) + /* If it can trap, it must be always executed in LOOP. + Readonly memory locations may trap when storing to them, but + tree_could_trap_p is a predicate for rvalues, so check that + explicitly. */ + base = get_base_address (ref->mem); + if ((tree_could_trap_p (ref->mem) + || (DECL_P (base) && TREE_READONLY (base))) + && !ref_always_accessed_p (loop, ref, true)) return false; /* And it must be independent on all other memory references |