passes: Fix up subobject __bos [PR101419]

The following testcase is miscompiled, because VN during cunrolli changes
__bos argument from address of a larger field to address of a smaller field
and so __builtin_object_size (, 1) then folds into smaller value than the
actually available size.
copy_reference_ops_from_ref has a hack for this, but it was using
cfun->after_inlining as a check whether the hack can be ignored, and
cunrolli is after_inlining.

This patch uses a property to make it exact (set at the end of objsz
pass that doesn't do insert_min_max_p) and additionally based on discussions
in the PR moves the objsz pass earlier after IPA.

2021-07-13  Jakub Jelinek  <jakub@redhat.com>
	    Richard Biener  <rguenther@suse.de>

	PR tree-optimization/101419
	* tree-pass.h (PROP_objsz): Define.
	(make_pass_early_object_sizes): Declare.
	* passes.def (pass_all_early_optimizations): Rename pass_object_sizes
	there to pass_early_object_sizes, drop parameter.
	(pass_all_optimizations): Move pass_object_sizes right after pass_ccp,
	drop parameter, move pass_post_ipa_warn right after that.
	* tree-object-size.c (pass_object_sizes::execute): Rename to...
	(object_sizes_execute): ... this.  Add insert_min_max_p argument.
	(pass_data_object_sizes): Move after object_sizes_execute.
	(pass_object_sizes): Likewise.  In execute method call
	object_sizes_execute, drop set_pass_param method and insert_min_max_p
	non-static data member and its initializer in the ctor.
	(pass_data_early_object_sizes, pass_early_object_sizes,
	make_pass_early_object_sizes): New.
	* tree-ssa-sccvn.c (copy_reference_ops_from_ref): Use
	(cfun->curr_properties & PROP_objsz) instead of cfun->after_inlining.

	* gcc.dg/builtin-object-size-10.c: Pass -fdump-tree-early_objsz-details
	instead of -fdump-tree-objsz1-details in dg-options and adjust names
	of dump file in scan-tree-dump.
	* gcc.dg/pr101419.c: New test.

diff --git a/gcc/passes.def b/gcc/passes.def
index 945d2bc..f5d88a6 100644 (file)
--- a/gcc/passes.def
+++ b/gcc/passes.def
@@ -74,7 +74,7 @@ along with GCC; see the file COPYING3.  If not see
       NEXT_PASS (pass_all_early_optimizations);
       PUSH_INSERT_PASSES_WITHIN (pass_all_early_optimizations)
          NEXT_PASS (pass_remove_cgraph_callee_edges);
-         NEXT_PASS (pass_object_sizes, true /* insert_min_max_p */);
+         NEXT_PASS (pass_early_object_sizes);
          /* Don't record nonzero bits before IPA to avoid
             using too much memory.  */
          NEXT_PASS (pass_ccp, false /* nonzero_p */);
@@ -194,14 +194,14 @@ along with GCC; see the file COPYING3.  If not see
         They ensure memory accesses are not indirect wherever possible.  */
       NEXT_PASS (pass_strip_predict_hints, false /* early_p */);
       NEXT_PASS (pass_ccp, true /* nonzero_p */);
-      NEXT_PASS (pass_post_ipa_warn);
       /* After CCP we rewrite no longer addressed locals into SSA
         form if possible.  */
+      NEXT_PASS (pass_object_sizes);
+      NEXT_PASS (pass_post_ipa_warn);
       NEXT_PASS (pass_complete_unrolli);
       NEXT_PASS (pass_backprop);
       NEXT_PASS (pass_phiprop);
       NEXT_PASS (pass_forwprop);
-      NEXT_PASS (pass_object_sizes, false /* insert_min_max_p */);
       /* pass_build_alias is a dummy pass that ensures that we
         execute TODO_rebuild_alias at this point.  */
       NEXT_PASS (pass_build_alias);

diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-10.c b/gcc/testsuite/gcc.dg/builtin-object-size-10.c
index 2a212fa..bfcdf5c 100644 (file)
--- a/gcc/testsuite/gcc.dg/builtin-object-size-10.c
+++ b/gcc/testsuite/gcc.dg/builtin-object-size-10.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-objsz1-details" } */
+/* { dg-options "-O2 -fdump-tree-early_objsz-details" } */
 // { dg-skip-if "packed attribute missing for drone_source_packet" { "epiphany-*-*" } }
 
 typedef struct {
@@ -22,5 +22,5 @@ foo(char *x)
   return dpkt;
 }
 
-/* { dg-final { scan-tree-dump "maximum object size 21" "objsz1" } } */
-/* { dg-final { scan-tree-dump "maximum subobject size 16" "objsz1" } } */
+/* { dg-final { scan-tree-dump "maximum object size 21" "early_objsz" } } */
+/* { dg-final { scan-tree-dump "maximum subobject size 16" "early_objsz" } } */

diff --git a/gcc/testsuite/gcc.dg/pr101419.c b/gcc/testsuite/gcc.dg/pr101419.c
new file mode 100644 (file)
index 0000000..2cce383
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr101419.c
@@ -0,0 +1,62 @@
+/* PR tree-optimization/101419 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+typedef __SIZE_TYPE__ size_t;
+void baz (int, int) __attribute__((__warning__("detected overflow")));
+
+union U {
+  int i;
+  char c;
+};
+
+static void
+foo (union U *u)
+{
+  if (__builtin_object_size (&u->c, 1) < sizeof (u->c))
+    baz (__builtin_object_size (&u->c, 1), sizeof (u->c));     /* { dg-bogus "detected overflow" } */
+  __builtin_memset (&u->c, 0, sizeof (u->c));
+
+  if (__builtin_object_size (&u->i, 1) < sizeof (u->i))
+    baz (__builtin_object_size (&u->i, 1), sizeof (u->i));     /* { dg-bogus "detected overflow" } */
+  __builtin_memset (&u->i, 0, sizeof (u->i));
+}
+
+void
+bar (union U *u)
+{
+  int i, j;
+  for (i = 0; i < 1; i++)
+    {
+      foo (u);
+      for (j = 0; j < 2; j++)
+        asm volatile ("");
+    }
+}
+
+static void
+qux (void *p, size_t q)
+{
+  if (__builtin_object_size (p, 1) < q)
+    baz (__builtin_object_size (p, 1), q);                     /* { dg-bogus "detected overflow" } */
+  __builtin_memset (p, 0, q);
+}
+
+static void
+corge (union U *u)
+{
+  qux (&u->c, sizeof (u->c));
+  qux (&u->i, sizeof (u->i));
+}
+
+void
+garply (union U *u)
+{
+  int i, j;
+  for (i = 0; i < 1; i++)
+    {
+      corge (u);
+      for (j = 0; j < 2; j++)
+        asm volatile ("");
+    }
+}

diff --git a/gcc/tree-object-size.c b/gcc/tree-object-size.c
index 13be7f4..744748d 100644 (file)
--- a/gcc/tree-object-size.c
+++ b/gcc/tree-object-size.c
@@ -1304,45 +1304,6 @@ fini_object_sizes (void)
     }
 }
 
-
-/* Simple pass to optimize all __builtin_object_size () builtins.  */
-
-namespace {
-
-const pass_data pass_data_object_sizes =
-{
-  GIMPLE_PASS, /* type */
-  "objsz", /* name */
-  OPTGROUP_NONE, /* optinfo_flags */
-  TV_NONE, /* tv_id */
-  ( PROP_cfg | PROP_ssa ), /* properties_required */
-  0, /* properties_provided */
-  0, /* properties_destroyed */
-  0, /* todo_flags_start */
-  0, /* todo_flags_finish */
-};
-
-class pass_object_sizes : public gimple_opt_pass
-{
-public:
-  pass_object_sizes (gcc::context *ctxt)
-    : gimple_opt_pass (pass_data_object_sizes, ctxt), insert_min_max_p (false)
-  {}
-
-  /* opt_pass methods: */
-  opt_pass * clone () { return new pass_object_sizes (m_ctxt); }
-  void set_pass_param (unsigned int n, bool param)
-    {
-      gcc_assert (n == 0);
-      insert_min_max_p = param;
-    }
-  virtual unsigned int execute (function *);
-
- private:
-  /* Determines whether the pass instance creates MIN/MAX_EXPRs.  */
-  bool insert_min_max_p;
-}; // class pass_object_sizes
-
 /* Dummy valueize function.  */
 
 static tree
@@ -1351,8 +1312,8 @@ do_valueize (tree t)
   return t;
 }
 
-unsigned int
-pass_object_sizes::execute (function *fun)
+static unsigned int
+object_sizes_execute (function *fun, bool insert_min_max_p)
 {
   basic_block bb;
   FOR_EACH_BB_FN (bb, fun)
@@ -1453,6 +1414,38 @@ pass_object_sizes::execute (function *fun)
   return 0;
 }
 
+/* Simple pass to optimize all __builtin_object_size () builtins.  */
+
+namespace {
+
+const pass_data pass_data_object_sizes =
+{
+  GIMPLE_PASS, /* type */
+  "objsz", /* name */
+  OPTGROUP_NONE, /* optinfo_flags */
+  TV_NONE, /* tv_id */
+  ( PROP_cfg | PROP_ssa ), /* properties_required */
+  PROP_objsz, /* properties_provided */
+  0, /* properties_destroyed */
+  0, /* todo_flags_start */
+  0, /* todo_flags_finish */
+};
+
+class pass_object_sizes : public gimple_opt_pass
+{
+public:
+  pass_object_sizes (gcc::context *ctxt)
+    : gimple_opt_pass (pass_data_object_sizes, ctxt)
+  {}
+
+  /* opt_pass methods: */
+  opt_pass * clone () { return new pass_object_sizes (m_ctxt); }
+  virtual unsigned int execute (function *fun)
+  {
+    return object_sizes_execute (fun, false);
+  }
+}; // class pass_object_sizes
+
 } // anon namespace
 
 gimple_opt_pass *
@@ -1460,3 +1453,42 @@ make_pass_object_sizes (gcc::context *ctxt)
 {
   return new pass_object_sizes (ctxt);
 }
+
+/* Early version of pass to optimize all __builtin_object_size () builtins.  */
+
+namespace {
+
+const pass_data pass_data_early_object_sizes =
+{
+  GIMPLE_PASS, /* type */
+  "early_objsz", /* name */
+  OPTGROUP_NONE, /* optinfo_flags */
+  TV_NONE, /* tv_id */
+  ( PROP_cfg | PROP_ssa ), /* properties_required */
+  0, /* properties_provided */
+  0, /* properties_destroyed */
+  0, /* todo_flags_start */
+  0, /* todo_flags_finish */
+};
+
+class pass_early_object_sizes : public gimple_opt_pass
+{
+public:
+  pass_early_object_sizes (gcc::context *ctxt)
+    : gimple_opt_pass (pass_data_early_object_sizes, ctxt)
+  {}
+
+  /* opt_pass methods: */
+  virtual unsigned int execute (function *fun)
+  {
+    return object_sizes_execute (fun, true);
+  }
+}; // class pass_object_sizes
+
+} // anon namespace
+
+gimple_opt_pass *
+make_pass_early_object_sizes (gcc::context *ctxt)
+{
+  return new pass_early_object_sizes (ctxt);
+}

diff --git a/gcc/tree-pass.h b/gcc/tree-pass.h
index 15693fe..aa9757a 100644 (file)
--- a/gcc/tree-pass.h
+++ b/gcc/tree-pass.h
@@ -208,6 +208,7 @@ protected:
 #define PROP_gimple_lcf                (1 << 1)        /* lowered control flow */
 #define PROP_gimple_leh                (1 << 2)        /* lowered eh */
 #define PROP_cfg               (1 << 3)
+#define PROP_objsz             (1 << 4)        /* object sizes computed */
 #define PROP_ssa               (1 << 5)
 #define PROP_no_crit_edges      (1 << 6)
 #define PROP_rtl               (1 << 7)
@@ -426,6 +427,7 @@ extern gimple_opt_pass *make_pass_omp_target_link (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_oacc_device_lower (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_omp_device_lower (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_object_sizes (gcc::context *ctxt);
+extern gimple_opt_pass *make_pass_early_object_sizes (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_warn_printf (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_strlen (gcc::context *ctxt);
 extern gimple_opt_pass *make_pass_fold_builtins (gcc::context *ctxt);

diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index 64e3a70..d6aee2e 100644 (file)
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -925,12 +925,10 @@ copy_reference_ops_from_ref (tree ref, vec<vn_reference_op_s> *result)
                         + (wi::to_offset (bit_offset) >> LOG2_BITS_PER_UNIT));
                    /* Probibit value-numbering zero offset components
                       of addresses the same before the pass folding
-                      __builtin_object_size had a chance to run
-                      (checking cfun->after_inlining does the
-                      trick here).  */
+                      __builtin_object_size had a chance to run.  */
                    if (TREE_CODE (orig) != ADDR_EXPR
                        || maybe_ne (off, 0)
-                       || cfun->after_inlining)
+                       || (cfun->curr_properties & PROP_objsz))
                      off.to_shwi (&temp.off);
                  }
              }