* Integrate alias analysis changes from jfc@mit.edu

        * Makefile.in (OBJS): Add alias.o
        (alias.o): Add dependencies.
        * alias.c: New file.
        * sched.c: Remove alias analysis code.  It lives in alias.c now.
        (reg_last_uses_size): Declare.
        (sched_analyze_2): Add new arguments to true_dependence.
        (sched_analyze_insn): Use reg_last_uses_size instead of max_reg.
        (schedule_block): Initialize reg_last_uses_size.
        (schedule_insns): Always call init_alias_analysis.
        * calls.c (expand_call): Note calls to malloc, calloc, and realloc;
        mark return value from such functions as a pointer and keep track of
        them for alias analysis.  If a return value from a function is a
        pointer, mark it as such.
        * combine.c (distribute_notes): Handle REG_NOALIAS.
        * cse.c (struct write_data): Delete.  No longer needed.
        (invalidate): Don't call set_nonvarying_address_components anymore.
        Use true_dependence to decide if an entry should be removed from
        the hash table.
        (invalidate_memory): Remove WRITES argument, simplify appropriately.
        Fix all callers.
        (note_mem_written): Similarly for WRITE_PTR argument.
        (invalidate_from_clobbers): Similarly for W argument.
        (invalidate_for_call): Remove memory elements from the hash table.
        (refers_to_mem_p, cse_rtx_addr_varies_p): Deleted.
        (cse_rtx_varies_p): New function.  Derived from old
        cse_rtx_addr_varies_p.
        (cse_insn): Remove WRITES_MEMORY and INIT variables and all references.
        Don't call note_mem_written anymore.  Stack pushes invalidate the stack
        pointer if PUSH_ROUNDING is defined.  No longer need to call
        cse_rtx_addr_varies_p to decide if a MEM should be invalidated.
        (skipped_writes_memory): Remove variable.
        (invalidate_skipped_set): Simplify and wewrite to use invalidate_memory.
        (invalidate_skipped_block): Simplify for new alias analysis code.
        (cse_set_around_loop): Likewise.
        (cse_main): Call init_alias_analysis.
        * flags.h (flag_alias_check, flag_argument_noalias): Declare.
        * toplev.c (flag_alias_check, flag_argument_noalias): Define.
        (f_options): Add new alias checking arguments.
        (main): Set flag_alias_check when optimizing.
        * local_alloc (validate_equiv_mem_from_store): Add new arguments
        to true_dependence.
        (memref_referenced_p): Likewise.
        * loop.c (NUM_STORES): Increase to 30.
        (prescan_loop): Only non-constant calls set unknown_address_altered.
        (invariant_p): Add new arguments to true_dependence.
        (record_giv): Initialize unrolled and shared fields.
        (emit_iv_add_mult): Call record_base_value as needed.
        * loop.h (struct induction): Add unrolled and shared fields.
        * unroll.c  (unroll_loop): Call record_base_value as needed.
        (copy_loop_body): Likewise.
        (final_biv_value): Likewise.
        (final_giv_value): Likewise.
        (find_splittable_regs): Likewise.  Only create one new pseudo
        if we have multiple address GIVs that were combined with the same
        dst_reg GIV.  Note when a new register is created due to unrolling.
        * rtl.c (reg_note_name): Add REG_NOALIAS.
        * rtl.h (enum reg_note): Similarly.
        (rtx_varies_p, may_trap_p, side_effects_p): Declare.
        (volatile_refs_p, volatile_insn_p, remove_note): Likewise.
        (note_stores, refers_to_regno_p, reg_overlap_mentioned_p): Likewise.
        (true_dependence, read_dependence, anti_dependence): Likewise.
        (output_dependence, init_alias_analysis, end_alias_analysis): Likewise.
        (mark_user_reg, mark_reg_pointer): Likewise.
jfc's alias analysis code.

From-SVN: r14768

1 files changed, 9 insertions, 5 deletions

diff --git a/gcc/loop.c b/gcc/loop.c
index 1c67f1c..b54e677 100644
--- a/gcc/loop.c
+++ b/gcc/loop.c
@@ -111,8 +111,7 @@ int *loop_number_exit_count;
 
 unsigned HOST_WIDE_INT loop_n_iterations;
 
-/* Nonzero if there is a subroutine call in the current loop.
-   (unknown_address_altered is also nonzero in this case.)  */
+/* Nonzero if there is a subroutine call in the current loop.  */
 
 static int loop_has_call;
 
@@ -160,7 +159,7 @@ static char *moved_once;
 /* Array of MEMs that are stored in this loop. If there are too many to fit
    here, we just turn on unknown_address_altered.  */
 
-#define NUM_STORES 20
+#define NUM_STORES 30
 static rtx loop_store_mems[NUM_STORES];
 
 /* Index of first available slot in above array.  */
@@ -2199,7 +2198,8 @@ prescan_loop (start, end)
 	}
       else if (GET_CODE (insn) == CALL_INSN)
 	{
-	  unknown_address_altered = 1;
+	  if (! CONST_CALL_P (insn))
+	    unknown_address_altered = 1;
 	  loop_has_call = 1;
 	}
       else
@@ -2795,7 +2795,7 @@ invariant_p (x)
 
       /* See if there is any dependence between a store and this load.  */
       for (i = loop_store_mems_idx - 1; i >= 0; i--)
-	if (true_dependence (loop_store_mems[i], x))
+	if (true_dependence (loop_store_mems[i], VOIDmode, x, rtx_varies_p))
 	  return 0;
 
       /* It's not invalidated by a store in memory
@@ -4523,6 +4523,8 @@ record_giv (v, insn, src_reg, dest_reg, mult_val, add_val, benefit,
   v->final_value = 0;
   v->same_insn = 0;
   v->auto_inc_opt = 0;
+  v->unrolled = 0;
+  v->shared = 0;
 
   /* The v->always_computable field is used in update_giv_derive, to
      determine whether a giv can be used to derive another giv.  For a
@@ -5771,6 +5773,8 @@ emit_iv_add_mult (b, m, a, reg, insert_before)
   end_sequence ();
 
   emit_insn_before (seq, insert_before);
+
+  record_base_value (REGNO (reg), b);
 }
 
 /* Test whether A * B can be computed without