Re: PATCH: PR middle-end/60013: [4.9 Regression] Build of 176.gcc from CPU2000 loops in cc1 starting with r207231

[Jan Hubicka <hubicka at ucw dot cz>]

> 
> basic block 13 only contains
> 
>   ABNORMAL_DISPATCHER (0);
> 
> which is an internal function and will be expanded to empty block:
> 
> ;; Generating RTL for gimple basic block 13
> 
> ;; ABNORMAL_DISPATCHER (0); 
> 
> (nil)
> 
> compute_bb_predicates goes into an infinite loop due to

OK, how does it make compute_bb_predicates to go into an infinite loop?

I do not see why we would need to specifically ignore BBs with the dispatcher
here, bug it looks like some big in the termination of dataflow perhaps related
to internal function?

I will try to check.
Honza
> 
> ;;   basic block 13, loop depth 0
> ;;    pred:       4
> ;;                14
> ;;                5
> ;;                6
> ;;                7
> ;;                10
>   ABNORMAL_DISPATCHER (0);
> ;;    succ:       12
> 
> This patch changes compute_bb_predicates to skip basic blocks containing
> IFN_ABNORMAL_DISPATCHER and updates estimate_function_body_sizes to use
> Use false predicate if aux is NULL.
> 
> Tested on Linux/x86-64 with:
> 
> --enable-languages=c,c++,fortran,java,lto,objc,ada,obj-c++,go
> 
> and make check RUNTESTFLAGS="--target_board='unix{-m32,}'".  OK for
> trunk?
> 
> Thanks.
> 
> H.J.
> --
> gcc/
> 
> 2014-02-02  H.J. Lu  <hongjiu.lu@intel.com>
> 
> 	PR middle-end/60013
> 	* basic-block.h (bb_has_abnormal_dispatcher): New prototype.
> 	* ipa-inline-analysis.c (compute_bb_predicates): Skip basic block
> 	containing IFN_ABNORMAL_DISPATCHER when computing predicate.
> 	(estimate_function_body_sizes): Use false predicate if aux is
> 	NULL.
> 	* tree-cfg.c (bb_has_abnormal_dispatcher): New functiom.
> 
> gcc/testsuite/
> 
> 2014-02-02  H.J. Lu  <hongjiu.lu@intel.com>
> 
> 	PR middle-end/60013
> 	* gcc.dg/torture/pr60013.c: New test.
> 
> diff --git a/gcc/basic-block.h b/gcc/basic-block.h
> index 82729b4..4cb0238 100644
> --- a/gcc/basic-block.h
> +++ b/gcc/basic-block.h
> @@ -942,6 +942,9 @@ extern void default_rtl_profile (void);
>  typedef struct gcov_working_set_info gcov_working_set_t;
>  extern gcov_working_set_t *find_working_set (unsigned pct_times_10);
>  
> +/* In tree-cfg.c.  */
> +extern bool bb_has_abnormal_dispatcher (basic_block bb);
> +
>  /* Check tha probability is sane.  */
>  
>  static inline void
> diff --git a/gcc/ipa-inline-analysis.c b/gcc/ipa-inline-analysis.c
> index ffb8264..dc3ebe1 100644
> --- a/gcc/ipa-inline-analysis.c
> +++ b/gcc/ipa-inline-analysis.c
> @@ -1860,21 +1860,24 @@ compute_bb_predicates (struct cgraph_node *node,
>  	  struct predicate p = false_predicate ();
>  	  edge e;
>  	  edge_iterator ei;
> -	  FOR_EACH_EDGE (e, ei, bb->preds)
> -	    {
> -	      if (e->src->aux)
> -		{
> -		  struct predicate this_bb_predicate
> -		    = *(struct predicate *) e->src->aux;
> -		  if (e->aux)
> -		    this_bb_predicate
> -		      = and_predicates (summary->conds, &this_bb_predicate,
> -					(struct predicate *) e->aux);
> -		  p = or_predicates (summary->conds, &p, &this_bb_predicate);
> -		  if (true_predicate_p (&p))
> -		    break;
> -		}
> -	    }
> +	  if (!bb_has_abnormal_dispatcher (bb))
> +	    FOR_EACH_EDGE (e, ei, bb->preds)
> +	      {
> +		if (e->src->aux)
> +		  {
> +		    struct predicate this_bb_predicate
> +		      = *(struct predicate *) e->src->aux;
> +		    if (e->aux)
> +		      this_bb_predicate
> +			= and_predicates (summary->conds,
> +					  &this_bb_predicate,
> +					  (struct predicate *) e->aux);
> +		    p = or_predicates (summary->conds, &p,
> +				       &this_bb_predicate);
> +		    if (true_predicate_p (&p))
> +		      break;
> +		  }
> +	      }
>  	  if (false_predicate_p (&p))
>  	    gcc_assert (!bb->aux);
>  	  else
> @@ -2703,7 +2706,10 @@ estimate_function_body_sizes (struct cgraph_node *node, bool early)
>  	  for (i = 0; i < loop->num_nodes; i++)
>  	    {
>  	      gimple_stmt_iterator gsi;
> -	      bb_predicate = *(struct predicate *) body[i]->aux;
> +	      if (body[i]->aux)
> +		bb_predicate = *(struct predicate *) body[i]->aux;
> +	      else
> +		bb_predicate = false_predicate ();
>  	      for (gsi = gsi_start_bb (body[i]); !gsi_end_p (gsi);
>  		   gsi_next (&gsi))
>  		{
> diff --git a/gcc/testsuite/gcc.dg/torture/pr60013.c b/gcc/testsuite/gcc.dg/torture/pr60013.c
> new file mode 100644
> index 0000000..e9d7c4e
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/torture/pr60013.c
> @@ -0,0 +1,102 @@
> +/* { dg-do compile } */
> +
> +#include <setjmp.h>
> +
> +enum tree_code {
> +  INTEGER_CST,
> +  REAL_CST,
> +  CEIL_MOD_EXPR,
> +  FLOOR_MOD_EXPR,
> +  EXACT_DIV_EXPR,
> +  CEIL_DIV_EXPR,
> +  FLOOR_DIV_EXPR,
> +  PLUS_EXPR,
> +  BIT_IOR_EXPR
> +};
> +typedef union tree_node *tree;
> +struct tree_common
> +{
> +  unsigned int code : 8;
> +  unsigned unsigned_flag : 1;
> +};
> +struct tree_int_cst
> +{
> +  char common[sizeof (struct tree_common)];
> +  int int_cst_low;
> +  int int_cst_high;
> +};
> +struct tree_real_cst
> +{
> +  char common[sizeof (struct tree_common)];
> +  double real_cst;
> +};
> +union tree_node
> +{
> +  struct tree_common common;
> +  struct tree_int_cst int_cst;
> +  struct tree_real_cst real_cst;
> +};
> +extern tree build_int_2_wide (int, int);
> +extern tree size_int (unsigned int);
> +extern tree copy_node (tree);
> +extern int target_isnan (double);
> +static jmp_buf float_error;
> +int
> +add_double (l1, h1, l2, h2, lv, hv)
> +	int l1, h1, l2, h2;
> +	int *lv, *hv;
> +{
> +  int l, h;
> +  l = l1 + l2;
> +  h = h1 + h2 + ((unsigned int) l < l1);
> +  *lv = l;
> +  *hv = h;
> +  return ((~((h1) ^ (h2)) & ((h1) ^ (h))) < 0);
> +}
> +tree
> +const_binop (code, arg1, arg2, notrunc)
> +	enum tree_code code;
> +	register tree arg1, arg2;
> +	int notrunc;
> +{
> +  if (((enum tree_code) (arg1)->common.code) == INTEGER_CST)
> +    {
> +      register int int1l = ((arg1)->int_cst.int_cst_low);
> +      register int int1h = ((arg1)->int_cst.int_cst_high);
> +      int int2l = ((arg2)->int_cst.int_cst_low);
> +      int int2h = ((arg2)->int_cst.int_cst_high);
> +      int low, hi;
> +      register tree t;
> +      int overflow = 0;
> +      switch (code)
> +	{
> +	case BIT_IOR_EXPR:
> +	  t = build_int_2_wide ((int) (int1l | int2l), (int) (int1h | int2h));
> +	  break;
> +	case PLUS_EXPR:
> +	  overflow = add_double (int1l, int1h, int2l, int2h, &low, &hi);
> +	  t = build_int_2_wide ((int) (low), (int) (hi));
> +	  break;
> +	case FLOOR_DIV_EXPR: case CEIL_DIV_EXPR:
> +	case EXACT_DIV_EXPR:
> +	  return size_int (int1l / int2l);
> +	case FLOOR_MOD_EXPR: case CEIL_MOD_EXPR:
> +	  t = build_int_2_wide ((int) (low), (int) (hi));
> +	  break;
> +	default:
> +	  break;
> +	}
> +      return t;
> +    }
> +  if (((enum tree_code) (arg1)->common.code) == REAL_CST)
> +    {
> +      tree t;
> +      double d2;
> +      d2 = ((arg2)->real_cst.real_cst);
> +      if ((target_isnan (d2)))
> +	return arg2;
> +      else if (_setjmp (float_error))
> +	t = copy_node (arg1);
> +    }
> +  return 0;
> +}
> diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
> index dfc9b7b..f1075fd 100644
> --- a/gcc/tree-cfg.c
> +++ b/gcc/tree-cfg.c
> @@ -599,6 +599,25 @@ get_abnormal_succ_dispatcher (basic_block bb)
>    return NULL;
>  }
>  
> +/* Return TRUE if basic block BB contains IFN_ABNORMAL_DISPATCHER
> +   internal call, otherwise return FALSE.  */
> +
> +bool
> +bb_has_abnormal_dispatcher (basic_block bb)
> +{
> +  gimple_stmt_iterator gsi;
> +  for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
> +    {
> +      gimple g = gsi_stmt (gsi);
> +      if (g
> +	  && is_gimple_call (g)
> +	  && gimple_call_internal_p (g)
> +	  && gimple_call_internal_fn (g) == IFN_ABNORMAL_DISPATCHER)
> +	return true;
> +    }
> +  return false;
> +}
> +
>  /* Helper function for make_edges.  Create a basic block with
>     with ABNORMAL_DISPATCHER internal call in it if needed, and
>     create abnormal edges from BBS to it and from it to FOR_BB