[2/5] Make vectorizable_operation punt early on codes it doesn't handle

[Richard Sandiford]

vectorizable_operation returned false for codes that are handled by
vectorizable_shift, but only after it had already done a lot of work.
Checking earlier should be more efficient and avoid polluting the logs
with duplicate info.

Also, there was no such early-out for comparisons or COND_EXPRs.
Fixing that avoids a false scan-tree-dump hit with a later patch.


2019-11-29  Richard Sandiford  <richard.sandif...@arm.com>

gcc/
        * tree-vect-stmts.c (vectorizable_operation): Punt early
        on codes that are handled elsewhere.

Index: gcc/tree-vect-stmts.c
===================================================================
--- gcc/tree-vect-stmts.c       2019-11-29 08:28:12.015121876 +0000
+++ gcc/tree-vect-stmts.c       2019-11-29 09:11:24.553108756 +0000
@@ -5999,6 +5999,21 @@ vectorizable_operation (stmt_vec_info st
 
   orig_code = code = gimple_assign_rhs_code (stmt);
 
+  /* Shifts are handled in vectorizable_shift.  */
+  if (code == LSHIFT_EXPR
+      || code == RSHIFT_EXPR
+      || code == LROTATE_EXPR
+      || code == RROTATE_EXPR)
+   return false;
+
+  /* Comparisons are handled in vectorizable_comparison.  */
+  if (TREE_CODE_CLASS (code) == tcc_comparison)
+    return false;
+
+  /* Conditions are handled in vectorizable_condition.  */
+  if (code == COND_EXPR)
+    return false;
+
   /* For pointer addition and subtraction, we should use the normal
      plus and minus for the vector operation.  */
   if (code == POINTER_PLUS_EXPR)
@@ -6123,11 +6138,6 @@ vectorizable_operation (stmt_vec_info st
 
   gcc_assert (ncopies >= 1);
 
-  /* Shifts are handled in vectorizable_shift ().  */
-  if (code == LSHIFT_EXPR || code == RSHIFT_EXPR || code == LROTATE_EXPR
-      || code == RROTATE_EXPR)
-   return false;
-
   /* Supportable by target?  */
 
   vec_mode = TYPE_MODE (vectype);