diff options
Diffstat (limited to 'gcc/tree-scalar-evolution.c')
| -rw-r--r-- | gcc/tree-scalar-evolution.c | 92 |
1 files changed, 59 insertions, 33 deletions
diff --git a/gcc/tree-scalar-evolution.c b/gcc/tree-scalar-evolution.c index de20d27..16debb0 100644 --- a/gcc/tree-scalar-evolution.c +++ b/gcc/tree-scalar-evolution.c @@ -380,6 +380,37 @@ find_var_scev_info (basic_block instantiated_below, tree var) return &res->chrec; } + +/* Hashtable helpers for a temporary hash-table used when + analyzing a scalar evolution, instantiating a CHREC or + resolving mixers. */ + +struct instantiate_cache_type +{ + htab_t map; + vec<scev_info_str> entries; + + instantiate_cache_type () : map (NULL), entries (vNULL) {} + ~instantiate_cache_type (); + tree get (unsigned slot) { return entries[slot].chrec; } + void set (unsigned slot, tree chrec) { entries[slot].chrec = chrec; } +}; + +instantiate_cache_type::~instantiate_cache_type () +{ + if (map != NULL) + { + htab_delete (map); + entries.release (); + } +} + +/* Cache to avoid infinite recursion when instantiating an SSA name. + Live during the outermost analyze_scalar_evolution, instantiate_scev + or resolve_mixers call. */ +static instantiate_cache_type *global_cache; + + /* Return true when CHREC contains symbolic names defined in LOOP_NB. */ @@ -2117,7 +2148,22 @@ analyze_scalar_evolution (struct loop *loop, tree var) res = get_scalar_evolution (block_before_loop (loop), var); if (res == chrec_not_analyzed_yet) - res = analyze_scalar_evolution_1 (loop, var); + { + /* We'll recurse into instantiate_scev, avoid tearing down the + instantiate cache repeatedly and keep it live from here. */ + bool destr = false; + if (!global_cache) + { + global_cache = new instantiate_cache_type; + destr = true; + } + res = analyze_scalar_evolution_1 (loop, var); + if (destr) + { + delete global_cache; + global_cache = NULL; + } + } if (dump_file && (dump_flags & TDF_SCEV)) fprintf (dump_file, ")\n"); @@ -2231,34 +2277,6 @@ analyze_scalar_evolution_in_loop (struct loop *wrto_loop, struct loop *use_loop, } -/* Hashtable helpers for a temporary hash-table used when - instantiating a CHREC or resolving mixers. For this use - instantiated_below is always the same. */ - -struct instantiate_cache_type -{ - htab_t map; - vec<scev_info_str> entries; - - instantiate_cache_type () : map (NULL), entries (vNULL) {} - ~instantiate_cache_type (); - tree get (unsigned slot) { return entries[slot].chrec; } - void set (unsigned slot, tree chrec) { entries[slot].chrec = chrec; } -}; - -instantiate_cache_type::~instantiate_cache_type () -{ - if (map != NULL) - { - htab_delete (map); - entries.release (); - } -} - -/* Cache to avoid infinite recursion when instantiating an SSA name. - Live during the outermost instantiate_scev or resolve_mixers call. */ -static instantiate_cache_type *global_cache; - /* Computes a hash function for database element ELT. */ static inline hashval_t @@ -2562,10 +2580,18 @@ instantiate_scev_binary (edge instantiate_below, if (op0 == chrec_dont_know) return chrec_dont_know; - op1 = instantiate_scev_r (instantiate_below, evolution_loop, inner_loop, - c1, fold_conversions, size_expr); - if (op1 == chrec_dont_know) - return chrec_dont_know; + /* While we eventually compute the same op1 if c0 == c1 the process + of doing this is expensive so the following short-cut prevents + exponential compile-time behavior. */ + if (c0 != c1) + { + op1 = instantiate_scev_r (instantiate_below, evolution_loop, inner_loop, + c1, fold_conversions, size_expr); + if (op1 == chrec_dont_know) + return chrec_dont_know; + } + else + op1 = op0; if (c0 != op0 || c1 != op1) |