[PATCH] Fix confusion about load_p in vect_build_slp_tree_1

[PATCH] Fix confusion about load_p in vect_build_slp_tree_1

[Richard Biener]

load_p is set and used as to whether the stmt is a memory operation,
not whether it is only a load.  The following renames it to ldst_p
to avoid this confusion.  It also replaces checking for a VUSE
with checking STMT_VINFO_DATA_REF since VUSE checking doesn't
work for pattern matched stores where no virtual operands are
present.  Where we want to distinguish between loads and stores
we then check DR_IS_READ/WRITE.

I've made a classification mistake with .MASK_STORE support and
this hits other complications when dealing with single-lane SLP.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

	* tree-vect-slp.cc (vect_build_slp_tree_1): Rename
	load_p to ldst_p, fix mistakes and rely on
	STMT_VINFO_DATA_REF.
---
 gcc/tree-vect-slp.cc | 42 ++++++++++++++++++++++++------------------
 1 file changed, 24 insertions(+), 18 deletions(-)

diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 0b1c2233017..0cf6e02285e 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -984,7 +984,7 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
   bool need_same_oprnds = false;
   tree vectype = NULL_TREE, first_op1 = NULL_TREE;
   stmt_vec_info first_load = NULL, prev_first_load = NULL;
-  bool first_stmt_load_p = false, load_p = false;
+  bool first_stmt_ldst_p = false, ldst_p = false;
   bool first_stmt_phi_p = false, phi_p = false;
   bool maybe_soft_fail = false;
   tree soft_fail_nunits_vectype = NULL_TREE;
@@ -1074,9 +1074,12 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
 	  if (cfn == CFN_MASK_LOAD
 	      || cfn == CFN_GATHER_LOAD
 	      || cfn == CFN_MASK_GATHER_LOAD)
-	    load_p = true;
+	    ldst_p = true;
 	  else if (cfn == CFN_MASK_STORE)
-	    rhs_code = CFN_MASK_STORE;
+	    {
+	      ldst_p = true;
+	      rhs_code = CFN_MASK_STORE;
+	    }
 	  else if ((internal_fn_p (cfn)
 		    && !vectorizable_internal_fn_p (as_internal_fn (cfn)))
 		   || gimple_call_tail_p (call_stmt)
@@ -1102,7 +1105,7 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
       else
 	{
 	  rhs_code = gimple_assign_rhs_code (stmt);
-	  load_p = gimple_vuse (stmt);
+	  ldst_p = STMT_VINFO_DATA_REF (stmt_info) != nullptr;
 	}
 
       /* Check the operation.  */
@@ -1110,7 +1113,7 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
 	{
 	  *node_vectype = vectype;
 	  first_stmt_code = rhs_code;
-	  first_stmt_load_p = load_p;
+	  first_stmt_ldst_p = ldst_p;
 	  first_stmt_phi_p = phi_p;
 
 	  /* Shift arguments should be equal in all the packed stmts for a
@@ -1144,7 +1147,7 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
               need_same_oprnds = true;
               first_op1 = gimple_assign_rhs2 (stmt);
             }
-	  else if (!load_p
+	  else if (!ldst_p
 		   && rhs_code == BIT_FIELD_REF)
 	    {
 	      tree vec = TREE_OPERAND (gimple_assign_rhs1 (stmt), 0);
@@ -1207,7 +1210,7 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
 			|| rhs_code == INDIRECT_REF
 			|| rhs_code == COMPONENT_REF
 			|| rhs_code == MEM_REF)))
-	      || first_stmt_load_p != load_p
+	      || first_stmt_ldst_p != ldst_p
 	      || first_stmt_phi_p != phi_p)
 	    {
 	      if (dump_enabled_p ())
@@ -1222,7 +1225,7 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
 	      continue;
 	    }
 
-	  if (!load_p
+	  if (!ldst_p
 	      && first_stmt_code == BIT_FIELD_REF
 	      && (TREE_OPERAND (gimple_assign_rhs1 (first_stmt_info->stmt), 0)
 		  != TREE_OPERAND (gimple_assign_rhs1 (stmt_info->stmt), 0)))
@@ -1291,12 +1294,13 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
       /* Grouped store or load.  */
       if (STMT_VINFO_GROUPED_ACCESS (stmt_info))
 	{
-	  if (!load_p)
+	  gcc_assert (ldst_p);
+	  if (DR_IS_WRITE (STMT_VINFO_DATA_REF (stmt_info)))
 	    {
 	      /* Store.  */
 	      gcc_assert (rhs_code == CFN_MASK_STORE
-			  || REFERENCE_CLASS_P (lhs));
-	      ;
+			  || REFERENCE_CLASS_P (lhs)
+			  || DECL_P (lhs));
 	    }
 	  else
 	    {
@@ -1321,10 +1325,11 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
               else
                 prev_first_load = first_load;
            }
-        } /* Grouped access.  */
-      else
+	}
+      /* Non-grouped store or load.  */
+      else if (ldst_p)
 	{
-	  if (load_p
+	  if (DR_IS_READ (STMT_VINFO_DATA_REF (stmt_info))
 	      && rhs_code != CFN_GATHER_LOAD
 	      && rhs_code != CFN_MASK_GATHER_LOAD
 	      /* Not grouped loads are handled as externals for BB
@@ -1345,10 +1350,11 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
 	      matches[0] = false;
 	      return false;
 	    }
-
-	  /* Not memory operation.  */
-	  if (!load_p
-	      && !phi_p
+	}
+      /* Not memory operation.  */
+      else
+	{
+	  if (!phi_p
 	      && rhs_code.is_tree_code ()
 	      && TREE_CODE_CLASS (tree_code (rhs_code)) != tcc_binary
 	      && TREE_CODE_CLASS (tree_code (rhs_code)) != tcc_unary
-- 
2.35.3