re PR tree-optimization/86214 (Strongly increased stack usage)

PR tree-optimization/86214
	* tree-inline.h (struct copy_body_data): Add
	add_clobbers_to_eh_landing_pads member.
	* tree-inline.c (add_clobbers_to_eh_landing_pad): New function.
	(copy_edges_for_bb): Call it if EH edge destination is <
	id->add_clobbers_to_eh_landing_pads.  Fix a comment typo.
	(expand_call_inline): Set id->add_clobbers_to_eh_landing_pads
	if flag_stack_reuse != SR_NONE and clear it afterwards.

	* g++.dg/opt/pr86214-1.C: New test.
	* g++.dg/opt/pr86214-2.C: New test.

From-SVN: r268067

gcc/ChangeLog

@@ -1,3 +1,14 @@
+2019-01-18  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/86214
+	* tree-inline.h (struct copy_body_data): Add
+	add_clobbers_to_eh_landing_pads member.
+	* tree-inline.c (add_clobbers_to_eh_landing_pad): New function.
+	(copy_edges_for_bb): Call it if EH edge destination is <
+	id->add_clobbers_to_eh_landing_pads.  Fix a comment typo.
+	(expand_call_inline): Set id->add_clobbers_to_eh_landing_pads
+	if flag_stack_reuse != SR_NONE and clear it afterwards.
+
 2019-01-18  Christophe Lyon  <christophe.lyon@linaro.org>
 
 	PR target/85596

gcc/testsuite/ChangeLog

@@ -1,3 +1,9 @@
+2019-01-18  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/86214
+	* g++.dg/opt/pr86214-1.C: New test.
+	* g++.dg/opt/pr86214-2.C: New test.
+
 2019-01-18  Christophe Lyon  <christophe.lyon@linaro.org>
 
 	* gcc.target/arm/pr77904.c: Add dg-warning for sp clobber.

gcc/testsuite/g++.dg/opt/pr86214-1.C

@@ -0,0 +1,30 @@
+// PR tree-optimization/86214
+// { dg-do compile }
+// { dg-options "-O2 -Wstack-usage=15000" }
+
+typedef __SIZE_TYPE__ size_t;
+struct A { A (); ~A (); int a; void qux (const char *); };
+int bar (char *);
+
+static inline A
+foo ()
+{
+  char b[8192];
+  int x = bar (b);
+  A s;
+  if (x > 0 && (size_t) x < sizeof b)
+    s.qux (b);
+  return s;
+}
+
+void
+baz ()	// { dg-bogus "stack usage is" }
+{
+  A a;
+  char c[1024];
+  bar (c);
+  foo (); foo (); foo (); foo (); foo ();
+  foo (); foo (); foo (); foo (); foo ();
+  foo (); foo (); foo (); foo (); foo ();
+  foo (); foo (); foo (); foo (); foo ();
+}

gcc/testsuite/g++.dg/opt/pr86214-2.C

@@ -0,0 +1,28 @@
+// PR tree-optimization/86214
+// { dg-do compile }
+// { dg-options "-O2 -Wstack-usage=15000" }
+
+typedef __SIZE_TYPE__ size_t;
+struct A { A (); ~A (); int a; void qux (const char *); };
+int bar (char *);
+
+static inline __attribute__((always_inline)) A
+foo ()
+{
+  char b[8192];
+  int x = bar (b);
+  A s;
+  if (x > 0 && (size_t) x < sizeof b)
+    s.qux (b);
+  return s;
+}
+
+void
+baz ()	// { dg-bogus "stack usage is" }
+{
+  A a;
+  foo (); foo (); foo (); foo (); foo ();
+  foo (); foo (); foo (); foo (); foo ();
+  foo (); foo (); foo (); foo (); foo ();
+  foo (); foo (); foo (); foo (); foo ();
+}

gcc/tree-inline.c

@@ -2190,6 +2190,40 @@ update_ssa_across_abnormal_edges (basic_block bb, basic_block ret_bb,
       }
 }
 
+/* Insert clobbers for automatic variables of inlined ID->src_fn
+   function at the start of basic block BB.  */
+
+static void
+add_clobbers_to_eh_landing_pad (basic_block bb, copy_body_data *id)
+{
+  tree var;
+  unsigned int i;
+  FOR_EACH_VEC_SAFE_ELT (id->src_cfun->local_decls, i, var)
+    if (VAR_P (var)
+	&& !DECL_HARD_REGISTER (var)
+	&& !TREE_THIS_VOLATILE (var)
+	&& !DECL_HAS_VALUE_EXPR_P (var)
+	&& !is_gimple_reg (var)
+	&& auto_var_in_fn_p (var, id->src_fn))
+      {
+	tree *t = id->decl_map->get (var);
+	if (!t)
+	  continue;
+	tree new_var = *t;
+	if (VAR_P (new_var)
+	    && !DECL_HARD_REGISTER (new_var)
+	    && !TREE_THIS_VOLATILE (new_var)
+	    && !DECL_HAS_VALUE_EXPR_P (new_var)
+	    && !is_gimple_reg (new_var)
+	    && auto_var_in_fn_p (new_var, id->dst_fn))
+	  {
+	    gimple_stmt_iterator gsi = gsi_after_labels (bb);
+	    tree clobber = build_clobber (TREE_TYPE (new_var));
+	    gimple *clobber_stmt = gimple_build_assign (new_var, clobber);
+	    gsi_insert_before (&gsi, clobber_stmt, GSI_NEW_STMT);
+	  }
+      }
+}
 
 /* Copy edges from BB into its copy constructed earlier, scale profile
    accordingly.  Edges will be taken care of later.  Assume aux
@@ -2232,7 +2266,7 @@ copy_edges_for_bb (basic_block bb, profile_count num, profile_count den,
   if (bb->index == ENTRY_BLOCK || bb->index == EXIT_BLOCK)
     return false;
 
-  /* When doing function splitting, we must decreate count of the return block
+  /* When doing function splitting, we must decrease count of the return block
      which was previously reachable by block we did not copy.  */
   if (single_succ_p (bb) && single_succ_edge (bb)->dest->index == EXIT_BLOCK)
     FOR_EACH_EDGE (old_edge, ei, bb->preds)
@@ -2317,8 +2351,16 @@ copy_edges_for_bb (basic_block bb, profile_count num, profile_count den,
 	      e->probability = old_edge->probability;
 	    
           FOR_EACH_EDGE (e, ei, copy_stmt_bb->succs)
-	    if ((e->flags & EDGE_EH) && !e->probability.initialized_p ())
-	      e->probability = profile_probability::never ();
+	    if (e->flags & EDGE_EH)
+	      {
+		if (!e->probability.initialized_p ())
+		  e->probability = profile_probability::never ();
+		if (e->dest->index < id->add_clobbers_to_eh_landing_pads)
+		  {
+		    add_clobbers_to_eh_landing_pad (e->dest, id);
+		    id->add_clobbers_to_eh_landing_pads = 0;
+		  }
+	      }
         }
 
 
@@ -4565,6 +4607,8 @@ expand_call_inline (basic_block bb, gimple *stmt, copy_body_data *id)
   id->decl_map = new hash_map<tree, tree>;
   dst = id->debug_map;
   id->debug_map = NULL;
+  if (flag_stack_reuse != SR_NONE)
+    id->add_clobbers_to_eh_landing_pads = last_basic_block_for_fn (cfun);
 
   /* Record the function we are about to inline.  */
   id->src_fn = fn;
@@ -4872,6 +4916,7 @@ expand_call_inline (basic_block bb, gimple *stmt, copy_body_data *id)
     }
 
   id->assign_stmts.release ();
+  id->add_clobbers_to_eh_landing_pads = 0;
 
   /* Output the inlining info for this abstract function, since it has been
      inlined.  If we don't do this now, we can lose the information about the

gcc/tree-inline.h

@@ -155,6 +155,12 @@ struct copy_body_data
   /* A list of addressable local variables remapped into the caller
      when inlining a call within an OpenMP SIMD-on-SIMT loop.  */
   vec<tree> *dst_simt_vars;
+
+  /* If clobbers for local variables from the inline function
+     that need to live in memory should be added to EH landing pads
+     outside of the inlined function, this should be the number
+     of basic blocks in the caller before inlining.  Zero otherwise.  */
+  int add_clobbers_to_eh_landing_pads;
 };
 
 /* Weights of constructions for estimate_num_insns.  */