diff options
Diffstat (limited to 'gcc/alias.c')
| -rw-r--r-- | gcc/alias.c | 114 |
1 files changed, 108 insertions, 6 deletions
diff --git a/gcc/alias.c b/gcc/alias.c index 2486001..e9cc2d8 100644 --- a/gcc/alias.c +++ b/gcc/alias.c @@ -46,6 +46,9 @@ along with GCC; see the file COPYING3. If not see #include "tree-pass.h" #include "ipa-type-escape.h" #include "df.h" +#include "tree-ssa-alias.h" +#include "pointer-set.h" +#include "tree-flow.h" /* The aliasing API provided here solves related but different problems: @@ -249,6 +252,98 @@ DEF_VEC_ALLOC_P(alias_set_entry,gc); /* The splay-tree used to store the various alias set entries. */ static GTY (()) VEC(alias_set_entry,gc) *alias_sets; +/* Build a decomposed reference object for querying the alias-oracle + from the MEM rtx and store it in *REF. + Returns false if MEM is not suitable for the alias-oracle. */ + +static bool +ao_ref_from_mem (ao_ref *ref, const_rtx mem) +{ + tree expr = MEM_EXPR (mem); + tree base; + + if (!expr) + return false; + + ao_ref_init (ref, expr); + + /* Get the base of the reference and see if we have to reject or + adjust it. */ + base = ao_ref_base (ref); + if (base == NULL_TREE) + return false; + + /* If this is a pointer dereference of a non-SSA_NAME punt. + ??? We could replace it with a pointer to anything. */ + if (INDIRECT_REF_P (base) + && TREE_CODE (TREE_OPERAND (base, 0)) != SSA_NAME) + return false; + + /* If this is a reference based on a partitioned decl replace the + base with an INDIRECT_REF of the pointer representative we + created during stack slot partitioning. */ + if (TREE_CODE (base) == VAR_DECL + && ! TREE_STATIC (base) + && cfun->gimple_df->decls_to_pointers != NULL) + { + void *namep; + namep = pointer_map_contains (cfun->gimple_df->decls_to_pointers, base); + if (namep) + { + ref->base_alias_set = get_alias_set (base); + ref->base = build1 (INDIRECT_REF, TREE_TYPE (base), *(tree *)namep); + } + } + + ref->ref_alias_set = MEM_ALIAS_SET (mem); + + /* For NULL MEM_OFFSET the MEM_EXPR may have been stripped arbitrarily + without recording offset or extent adjustments properly. */ + if (MEM_OFFSET (mem) == NULL_RTX) + { + ref->offset = 0; + ref->max_size = -1; + } + else + { + ref->offset += INTVAL (MEM_OFFSET (mem)) * BITS_PER_UNIT; + } + + /* NULL MEM_SIZE should not really happen with a non-NULL MEM_EXPR, + but just play safe here. The size may have been adjusted together + with the offset, so we need to take it if it is set and not rely + on MEM_EXPR here (which has the size determining parts potentially + stripped anyway). We lose precision for max_size which is only + available from the remaining MEM_EXPR. */ + if (MEM_SIZE (mem) == NULL_RTX) + { + ref->size = -1; + ref->max_size = -1; + } + else + { + ref->size = INTVAL (MEM_SIZE (mem)) * BITS_PER_UNIT; + } + + return true; +} + +/* Query the alias-oracle on whether the two memory rtx X and MEM may + alias. If TBAA_P is set also apply TBAA. Returns true if the + two rtxen may alias, false otherwise. */ + +static bool +rtx_refs_may_alias_p (const_rtx x, const_rtx mem, bool tbaa_p) +{ + ao_ref ref1, ref2; + + if (!ao_ref_from_mem (&ref1, x) + || !ao_ref_from_mem (&ref2, mem)) + return true; + + return refs_may_alias_p_1 (&ref1, &ref2, tbaa_p); +} + /* Returns a pointer to the alias set entry for ALIAS_SET, if there is such an entry, or NULL otherwise. */ @@ -2191,8 +2286,10 @@ true_dependence (const_rtx mem, enum machine_mode mem_mode, const_rtx x, if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) return 1; - return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, - varies); + if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies)) + return 0; + + return rtx_refs_may_alias_p (x, mem, true); } /* Canonical true dependence: X is read after store in MEM takes place. @@ -2255,8 +2352,10 @@ canon_true_dependence (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr, if (mem_mode == BLKmode || GET_MODE (x) == BLKmode) return 1; - return ! fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, - varies); + if (fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, varies)) + return 0; + + return rtx_refs_may_alias_p (x, mem, true); } /* Returns nonzero if a write to X might alias a previous read from @@ -2316,8 +2415,11 @@ write_dependence_p (const_rtx mem, const_rtx x, int writep) = fixed_scalar_and_varying_struct_p (mem, x, mem_addr, x_addr, rtx_addr_varies_p); - return (!(fixed_scalar == mem && !aliases_everything_p (x)) - && !(fixed_scalar == x && !aliases_everything_p (mem))); + if ((fixed_scalar == mem && !aliases_everything_p (x)) + || (fixed_scalar == x && !aliases_everything_p (mem))) + return 0; + + return rtx_refs_may_alias_p (x, mem, false); } /* Anti dependence: X is written after read in MEM takes place. */ |