openmp: Add testing checks (whether lhs appears in operands at all) to more trees

This patch adds testing checks (goa_stabilize_expr with NULL pre_p) for more
tree codes, so that we don't gimplify their operands individually unless lhs
appears in them.  Also, so that we don't have exponential compile time complexity
with the added checks, I've added a depth computation, we don't expect lhs
to be found in depth 8 or above as all the atomic forms must have x expression
in specific places in the expressions.

2021-09-14  Jakub Jelinek  <jakub@redhat.com>

	* gimplify.c (goa_stabilize_expr): Add depth argument, propagate
	it to recursive calls, for depth above 7 just gimplify or return.
	Perform a test even for MODIFY_EXPR, ADDR_EXPR, COMPOUND_EXPR with
	__builtin_clear_padding and TARGET_EXPR.
	(gimplify_omp_atomic): Adjust goa_stabilize_expr callers.

(cherry picked from commit 3f89d5ebcca8ea8c363db39cd3946db12b11adcc)

diff --git a/gcc/ChangeLog.omp b/gcc/ChangeLog.omp
index 015f1088d0604aa4c9693bfbb4f075f18944ddaf..0dcb12a5fb9e1f35a2b23d6df80d0d4d17ac9182 100644 (file)
--- a/gcc/ChangeLog.omp
+++ b/gcc/ChangeLog.omp
@@ -1,3 +1,14 @@
+2021-09-14  Tobias Burnus  <tobias@codesourcery.com>
+
+       Backported from master:
+       2021-09-14  Jakub Jelinek  <jakub@redhat.com>
+
+       * gimplify.c (goa_stabilize_expr): Add depth argument, propagate
+       it to recursive calls, for depth above 7 just gimplify or return.
+       Perform a test even for MODIFY_EXPR, ADDR_EXPR, COMPOUND_EXPR with
+       __builtin_clear_padding and TARGET_EXPR.
+       (gimplify_omp_atomic): Adjust goa_stabilize_expr callers.
+
 2021-09-13  Tobias Burnus  <tobias@codesourcery.com>
 
        Backported from master:

diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index 26c81dba67ce9ea3a42d6cb94c7c432fdf3ba273..03e601ce5695c70bc8d12b426c66c2dc8ace762f 100644 (file)
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -14703,10 +14703,10 @@ goa_lhs_expr_p (tree expr, tree addr)
 
 static int
 goa_stabilize_expr (tree *expr_p, gimple_seq *pre_p, tree lhs_addr,
-                   tree lhs_var, tree &target_expr, bool rhs)
+                   tree lhs_var, tree &target_expr, bool rhs, int depth)
 {
   tree expr = *expr_p;
-  int saw_lhs;
+  int saw_lhs = 0;
 
   if (goa_lhs_expr_p (expr, lhs_addr))
     {
@@ -14717,17 +14717,22 @@ goa_stabilize_expr (tree *expr_p, gimple_seq *pre_p, tree lhs_addr,
   if (is_gimple_val (expr))
     return 0;
 
-  saw_lhs = 0;
+  /* Maximum depth of lhs in expression is for the
+     __builtin_clear_padding (...), __builtin_clear_padding (...),
+     __builtin_memcmp (&TARGET_EXPR <lhs, >, ...) == 0 ? ... : lhs;  */
+  if (++depth > 7)
+    goto finish;
+
   switch (TREE_CODE_CLASS (TREE_CODE (expr)))
     {
     case tcc_binary:
     case tcc_comparison:
       saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 1), pre_p, lhs_addr,
-                                    lhs_var, target_expr, true);
+                                    lhs_var, target_expr, true, depth);
       /* FALLTHRU */
     case tcc_unary:
       saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 0), pre_p, lhs_addr,
-                                    lhs_var, target_expr, true);
+                                    lhs_var, target_expr, true, depth);
       break;
     case tcc_expression:
       switch (TREE_CODE (expr))
@@ -14739,84 +14744,101 @@ goa_stabilize_expr (tree *expr_p, gimple_seq *pre_p, tree lhs_addr,
        case TRUTH_XOR_EXPR:
        case BIT_INSERT_EXPR:
          saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 1), pre_p,
-                                        lhs_addr, lhs_var, target_expr, true);
+                                        lhs_addr, lhs_var, target_expr, true,
+                                        depth);
          /* FALLTHRU */
        case TRUTH_NOT_EXPR:
          saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 0), pre_p,
-                                        lhs_addr, lhs_var, target_expr, true);
+                                        lhs_addr, lhs_var, target_expr, true,
+                                        depth);
          break;
        case MODIFY_EXPR:
+         if (pre_p && !goa_stabilize_expr (expr_p, NULL, lhs_addr, lhs_var,
+                                           target_expr, true, depth))
+           break;
          saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 1), pre_p,
-                                        lhs_addr, lhs_var, target_expr, true);
+                                        lhs_addr, lhs_var, target_expr, true,
+                                        depth);
+         saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 0), pre_p,
+                                        lhs_addr, lhs_var, target_expr, false,
+                                        depth);
+         break;
          /* FALLTHRU */
        case ADDR_EXPR:
+         if (pre_p && !goa_stabilize_expr (expr_p, NULL, lhs_addr, lhs_var,
+                                           target_expr, true, depth))
+           break;
          saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 0), pre_p,
-                                        lhs_addr, lhs_var, target_expr, false);
+                                        lhs_addr, lhs_var, target_expr, false,
+                                        depth);
          break;
        case COMPOUND_EXPR:
-         /* Special-case __builtin_clear_padding call before
-            __builtin_memcmp.  */
-         if (TREE_CODE (TREE_OPERAND (expr, 0)) == CALL_EXPR)
+         /* Break out any preevaluations from cp_build_modify_expr.  */
+         for (; TREE_CODE (expr) == COMPOUND_EXPR;
+              expr = TREE_OPERAND (expr, 1))
            {
-             tree fndecl = get_callee_fndecl (TREE_OPERAND (expr, 0));
-             if (fndecl
-                 && fndecl_built_in_p (fndecl, BUILT_IN_CLEAR_PADDING)
-                 && VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0))))
+             /* Special-case __builtin_clear_padding call before
+                __builtin_memcmp.  */
+             if (TREE_CODE (TREE_OPERAND (expr, 0)) == CALL_EXPR)
                {
-                 saw_lhs = goa_stabilize_expr (&TREE_OPERAND (expr, 0), pre_p,
-                                               lhs_addr, lhs_var,
-                                               target_expr, true);
-                 if (!saw_lhs)
-                   {
-                     expr = TREE_OPERAND (expr, 1);
-                     if (!pre_p)
-                       return goa_stabilize_expr (&expr, pre_p, lhs_addr,
-                                                  lhs_var, target_expr, true);
-                     *expr_p = expr;
-                     return goa_stabilize_expr (expr_p, pre_p, lhs_addr,
-                                                lhs_var, target_expr, true);
-                   }
-                 else
+                 tree fndecl = get_callee_fndecl (TREE_OPERAND (expr, 0));
+                 if (fndecl
+                     && fndecl_built_in_p (fndecl, BUILT_IN_CLEAR_PADDING)
+                     && VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0)))
+                     && (!pre_p
+                         || goa_stabilize_expr (&TREE_OPERAND (expr, 0), NULL,
+                                                lhs_addr, lhs_var,
+                                                target_expr, true, depth)))
                    {
+                     if (pre_p)
+                       *expr_p = expr;
+                     saw_lhs = goa_stabilize_expr (&TREE_OPERAND (expr, 0),
+                                                   pre_p, lhs_addr, lhs_var,
+                                                   target_expr, true, depth);
                      saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 1),
                                                     pre_p, lhs_addr, lhs_var,
-                                                    target_expr, rhs);
-                     break;
+                                                    target_expr, rhs, depth);
+                     return saw_lhs;
                    }
                }
+
+             if (pre_p)
+               gimplify_stmt (&TREE_OPERAND (expr, 0), pre_p);
            }
-         /* Break out any preevaluations from cp_build_modify_expr.  */
-         for (; TREE_CODE (expr) == COMPOUND_EXPR;
-              expr = TREE_OPERAND (expr, 1))
-           if (pre_p)
-             gimplify_stmt (&TREE_OPERAND (expr, 0), pre_p);
          if (!pre_p)
            return goa_stabilize_expr (&expr, pre_p, lhs_addr, lhs_var,
-                                      target_expr, rhs);
+                                      target_expr, rhs, depth);
          *expr_p = expr;
          return goa_stabilize_expr (expr_p, pre_p, lhs_addr, lhs_var,
-                                    target_expr, rhs);
+                                    target_expr, rhs, depth);
        case COND_EXPR:
          if (!goa_stabilize_expr (&TREE_OPERAND (expr, 0), NULL, lhs_addr,
-                                  lhs_var, target_expr, true))
+                                  lhs_var, target_expr, true, depth))
            break;
          saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 0), pre_p,
-                                        lhs_addr, lhs_var, target_expr, true);
+                                        lhs_addr, lhs_var, target_expr, true,
+                                        depth);
          saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 1), pre_p,
-                                        lhs_addr, lhs_var, target_expr, true);
+                                        lhs_addr, lhs_var, target_expr, true,
+                                        depth);
          saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 2), pre_p,
-                                        lhs_addr, lhs_var, target_expr, true);
+                                        lhs_addr, lhs_var, target_expr, true,
+                                        depth);
          break;
        case TARGET_EXPR:
          if (TARGET_EXPR_INITIAL (expr))
            {
+             if (pre_p && !goa_stabilize_expr (expr_p, NULL, lhs_addr,
+                                               lhs_var, target_expr, true,
+                                               depth))
+               break;
              if (expr == target_expr)
                saw_lhs = 1;
              else
                {
                  saw_lhs = goa_stabilize_expr (&TARGET_EXPR_INITIAL (expr),
                                                pre_p, lhs_addr, lhs_var,
-                                               target_expr, true);
+                                               target_expr, true, depth);
                  if (saw_lhs && target_expr == NULL_TREE && pre_p)
                    target_expr = expr;
                }
@@ -14830,7 +14852,8 @@ goa_stabilize_expr (tree *expr_p, gimple_seq *pre_p, tree lhs_addr,
       if (TREE_CODE (expr) == BIT_FIELD_REF
          || TREE_CODE (expr) == VIEW_CONVERT_EXPR)
        saw_lhs |= goa_stabilize_expr (&TREE_OPERAND (expr, 0), pre_p,
-                                      lhs_addr, lhs_var, target_expr, true);
+                                      lhs_addr, lhs_var, target_expr, true,
+                                      depth);
       break;
     case tcc_vl_exp:
       if (TREE_CODE (expr) == CALL_EXPR)
@@ -14843,24 +14866,24 @@ goa_stabilize_expr (tree *expr_p, gimple_seq *pre_p, tree lhs_addr,
                for (int i = 0; i < nargs; i++)
                  saw_lhs |= goa_stabilize_expr (&CALL_EXPR_ARG (expr, i),
                                                 pre_p, lhs_addr, lhs_var,
-                                                target_expr, true);
+                                                target_expr, true, depth);
              }
-         if (saw_lhs == 0 && VOID_TYPE_P (TREE_TYPE (expr)))
-           {
-             if (pre_p)
-               gimplify_stmt (&expr, pre_p);
-             return 0;
-           }
        }
       break;
     default:
       break;
     }
 
+ finish:
   if (saw_lhs == 0 && pre_p)
     {
       enum gimplify_status gs;
-      if (rhs)
+      if (TREE_CODE (expr) == CALL_EXPR && VOID_TYPE_P (TREE_TYPE (expr)))
+       {
+         gimplify_stmt (&expr, pre_p);
+         return saw_lhs;
+       }
+      else if (rhs)
        gs = gimplify_expr (expr_p, pre_p, NULL, is_gimple_val, fb_rvalue);
       else
        gs = gimplify_expr (expr_p, pre_p, NULL, is_gimple_lvalue, fb_lvalue);
@@ -14888,7 +14911,7 @@ gimplify_omp_atomic (tree *expr_p, gimple_seq *pre_p)
   tmp_load = create_tmp_reg (type);
   if (rhs
       && goa_stabilize_expr (&rhs, pre_p, addr, tmp_load, target_expr,
-                            true) < 0)
+                            true, 0) < 0)
     return GS_ERROR;
 
   if (gimplify_expr (&addr, pre_p, NULL, is_gimple_val, fb_rvalue)