Use conditional internal functions in if-conversion

This patch uses IFN_COND_* to vectorise conditionally-executed,
potentially-trapping arithmetic, such as most floating-point
ops with -ftrapping-math.  E.g.:

    if (cond) { ... x = a + b; ... }

becomes:

    ...
    x = .COND_ADD (cond, a, b, else_value);
    ...

When this transformation is done on its own, the value of x for
!cond isn't important, so else_value is simply the target's
preferred_else_value (i.e. the value it can handle the most
efficiently).

However, the patch also looks for the equivalent of:

    y = cond ? x : c;

in which the "then" value is the result of the conditionally-executed
operation and the "else" value "c" is some value that is available at x.
In that case we can instead use:

    x = .COND_ADD (cond, a, b, c);

and replace uses of y with uses of x.

The patch also looks for:

    y = !cond ? c : x;

which can be transformed in the same way.  This involved adding a new
utility function inverse_conditions_p, which was already open-coded
in a more limited way in match.pd.

2018-07-12  Richard Sandiford  <richard.sandiford@linaro.org>

gcc/
	* fold-const.h (inverse_conditions_p): Declare.
	* fold-const.c (inverse_conditions_p): New function.
	* match.pd: Use inverse_conditions_p.  Add folds of view_converts
	that test the inverse condition of a conditional internal function.
	* internal-fn.h (vectorized_internal_fn_supported_p): Declare.
	* internal-fn.c (internal_fn_mask_index): Handle conditional
	internal functions.
	(vectorized_internal_fn_supported_p): New function.
	* tree-if-conv.c: Include internal-fn.h and fold-const.h.
	(any_pred_load_store): Replace with...
	(need_to_predicate): ...this new variable.
	(redundant_ssa_names): New variable.
	(ifcvt_can_use_mask_load_store): Move initial checks to...
	(ifcvt_can_predicate): ...this new function.  Handle tree codes
	for which a conditional internal function exists.
	(if_convertible_gimple_assign_stmt_p): Use ifcvt_can_predicate
	instead of ifcvt_can_use_mask_load_store.  Update after variable
	name change.
	(predicate_load_or_store): New function, split out from
	predicate_mem_writes.
	(check_redundant_cond_expr): New function.
	(value_available_p): Likewise.
	(predicate_rhs_code): Likewise.
	(predicate_mem_writes): Rename to...
	(predicate_statements): ...this.  Use predicate_load_or_store
	and predicate_rhs_code.
	(combine_blocks, tree_if_conversion): Update after above name changes.
	(ifcvt_local_dce): Handle redundant_ssa_names.
	* tree-vect-patterns.c (vect_recog_mask_conversion_pattern): Handle
	general conditional functions.
	* tree-vect-stmts.c (vectorizable_call): Likewise.

gcc/testsuite/
	* gcc.dg/vect/vect-cond-arith-4.c: New test.
	* gcc.dg/vect/vect-cond-arith-5.c: Likewise.
	* gcc.target/aarch64/sve/cond_arith_1.c: Likewise.
	* gcc.target/aarch64/sve/cond_arith_1_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_arith_2.c: Likewise.
	* gcc.target/aarch64/sve/cond_arith_2_run.c: Likewise.
	* gcc.target/aarch64/sve/cond_arith_3.c: Likewise.
	* gcc.target/aarch64/sve/cond_arith_3_run.c: Likewise.

From-SVN: r262589

1 files changed, 37 insertions, 34 deletions

diff --git a/gcc/tree-vect-patterns.c b/gcc/tree-vect-patterns.c
index 8e28950..4c22afd 100644
--- a/gcc/tree-vect-patterns.c
+++ b/gcc/tree-vect-patterns.c
@@ -3905,65 +3905,68 @@ vect_recog_mask_conversion_pattern (stmt_vec_info stmt_vinfo, tree *type_out)
 
   /* Check for MASK_LOAD ans MASK_STORE calls requiring mask conversion.  */
   if (is_gimple_call (last_stmt)
-      && gimple_call_internal_p (last_stmt)
-      && (gimple_call_internal_fn (last_stmt) == IFN_MASK_STORE
-	  || gimple_call_internal_fn (last_stmt) == IFN_MASK_LOAD))
+      && gimple_call_internal_p (last_stmt))
     {
       gcall *pattern_stmt;
-      bool load = (gimple_call_internal_fn (last_stmt) == IFN_MASK_LOAD);
 
-      if (load)
+      internal_fn ifn = gimple_call_internal_fn (last_stmt);
+      int mask_argno = internal_fn_mask_index (ifn);
+      if (mask_argno < 0)
+	return NULL;
+
+      bool store_p = internal_store_fn_p (ifn);
+      if (store_p)
 	{
-	  lhs = gimple_call_lhs (last_stmt);
-	  vectype1 = get_vectype_for_scalar_type (TREE_TYPE (lhs));
+	  int rhs_index = internal_fn_stored_value_index (ifn);
+	  tree rhs = gimple_call_arg (last_stmt, rhs_index);
+	  vectype1 = get_vectype_for_scalar_type (TREE_TYPE (rhs));
 	}
       else
 	{
-	  rhs2 = gimple_call_arg (last_stmt, 3);
-	  vectype1 = get_vectype_for_scalar_type (TREE_TYPE (rhs2));
+	  lhs = gimple_call_lhs (last_stmt);
+	  vectype1 = get_vectype_for_scalar_type (TREE_TYPE (lhs));
 	}
 
-      rhs1 = gimple_call_arg (last_stmt, 2);
-      rhs1_type = search_type_for_mask (rhs1, vinfo);
-      if (!rhs1_type)
+      tree mask_arg = gimple_call_arg (last_stmt, mask_argno);
+      tree mask_arg_type = search_type_for_mask (mask_arg, vinfo);
+      if (!mask_arg_type)
 	return NULL;
-      vectype2 = get_mask_type_for_scalar_type (rhs1_type);
+      vectype2 = get_mask_type_for_scalar_type (mask_arg_type);
 
       if (!vectype1 || !vectype2
 	  || known_eq (TYPE_VECTOR_SUBPARTS (vectype1),
 		       TYPE_VECTOR_SUBPARTS (vectype2)))
 	return NULL;
 
-      tmp = build_mask_conversion (rhs1, vectype1, stmt_vinfo);
+      tmp = build_mask_conversion (mask_arg, vectype1, stmt_vinfo);
 
-      if (load)
+      auto_vec<tree, 8> args;
+      unsigned int nargs = gimple_call_num_args (last_stmt);
+      args.safe_grow (nargs);
+      for (unsigned int i = 0; i < nargs; ++i)
+	args[i] = ((int) i == mask_argno
+		   ? tmp
+		   : gimple_call_arg (last_stmt, i));
+      pattern_stmt = gimple_build_call_internal_vec (ifn, args);
+
+      if (!store_p)
 	{
 	  lhs = vect_recog_temp_ssa_var (TREE_TYPE (lhs), NULL);
-	  pattern_stmt
-	    = gimple_build_call_internal (IFN_MASK_LOAD, 3,
-					  gimple_call_arg (last_stmt, 0),
-					  gimple_call_arg (last_stmt, 1),
-					  tmp);
 	  gimple_call_set_lhs (pattern_stmt, lhs);
 	}
-      else
-	  pattern_stmt
-	    = gimple_build_call_internal (IFN_MASK_STORE, 4,
-					  gimple_call_arg (last_stmt, 0),
-					  gimple_call_arg (last_stmt, 1),
-					  tmp,
-					  gimple_call_arg (last_stmt, 3));
-
       gimple_call_set_nothrow (pattern_stmt, true);
 
       pattern_stmt_info = new_stmt_vec_info (pattern_stmt, vinfo);
       set_vinfo_for_stmt (pattern_stmt, pattern_stmt_info);
-      STMT_VINFO_DATA_REF (pattern_stmt_info)
-	= STMT_VINFO_DATA_REF (stmt_vinfo);
-      STMT_VINFO_DR_WRT_VEC_LOOP (pattern_stmt_info)
-	= STMT_VINFO_DR_WRT_VEC_LOOP (stmt_vinfo);
-      STMT_VINFO_GATHER_SCATTER_P (pattern_stmt_info)
-	= STMT_VINFO_GATHER_SCATTER_P (stmt_vinfo);
+      if (STMT_VINFO_DATA_REF (stmt_vinfo))
+	{
+	  STMT_VINFO_DATA_REF (pattern_stmt_info)
+	    = STMT_VINFO_DATA_REF (stmt_vinfo);
+	  STMT_VINFO_DR_WRT_VEC_LOOP (pattern_stmt_info)
+	    = STMT_VINFO_DR_WRT_VEC_LOOP (stmt_vinfo);
+	  STMT_VINFO_GATHER_SCATTER_P (pattern_stmt_info)
+	    = STMT_VINFO_GATHER_SCATTER_P (stmt_vinfo);
+	}
 
       *type_out = vectype1;
       vect_pattern_detected ("vect_recog_mask_conversion_pattern", last_stmt);