Widening-Mul: Fix one bug of consume after phi node released

When try to matching saturation related pattern on PHI node, we may have
to try each pattern for all phi node of bb.  Aka:

for each PHI node in bb:
  gphi *phi = xxx;
  try_match_sat_add (, phi);
  try_match_sat_sub (, phi);
  try_match_sat_trunc (, phi);

The PHI node will be removed if one of the above 3 sat patterns are
matched.  There will be a problem that, for example, sat_add is
matched and then the phi is removed(freed), and the next 2 sat_sub and
sat_trunc will depend on the removed(freed) phi node.

This patch would like to fix this consume after phi node released issue.
To ensure at most one pattern of the above will be matched.

The below test suites are passed for this patch.
* The rv64gcv fully regression test.
* The x86 bootstrap test.
* The x86 fully regression test.

gcc/ChangeLog:

	* tree-ssa-math-opts.cc (build_saturation_binary_arith_call): Rename
	to...
	(build_saturation_binary_arith_call_and_replace): ...this.
	(build_saturation_binary_arith_call_and_insert): ...this.
	(match_unsigned_saturation_add): Leverage renamed func.
	(match_unsigned_saturation_sub): Ditto.
	(match_saturation_add): Return bool on matched and leverage
	renamed func.
	(match_saturation_sub): Ditto.
	(match_saturation_trunc): Ditto.
	(math_opts_dom_walker::after_dom_children): Ensure at most one
	pattern will be matched for each phi node.

Signed-off-by: Pan Li <pan2.li@intel.com>

diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index dad8428d3d8a7adb89f4dbb7e989bea29d3ae521..f9ccdf41d67f75fbc2b9cd55b3e665703c332b79 100644 (file)
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -4029,8 +4029,9 @@ extern bool gimple_signed_integer_sat_sub (tree, tree*, tree (*)(tree));
 extern bool gimple_signed_integer_sat_trunc (tree, tree*, tree (*)(tree));
 
 static void
-build_saturation_binary_arith_call (gimple_stmt_iterator *gsi, internal_fn fn,
-                                   tree lhs, tree op_0, tree op_1)
+build_saturation_binary_arith_call_and_replace (gimple_stmt_iterator *gsi,
+                                               internal_fn fn, tree lhs,
+                                               tree op_0, tree op_1)
 {
   if (direct_internal_fn_supported_p (fn, TREE_TYPE (lhs), OPTIMIZE_FOR_BOTH))
     {
@@ -4040,20 +4041,19 @@ build_saturation_binary_arith_call (gimple_stmt_iterator *gsi, internal_fn fn,
     }
 }
 
-static void
-build_saturation_binary_arith_call (gimple_stmt_iterator *gsi, gphi *phi,
-                                   internal_fn fn, tree lhs, tree op_0,
-                                   tree op_1)
+static bool
+build_saturation_binary_arith_call_and_insert (gimple_stmt_iterator *gsi,
+                                              internal_fn fn, tree lhs,
+                                              tree op_0, tree op_1)
 {
-  if (direct_internal_fn_supported_p (fn, TREE_TYPE (op_0), OPTIMIZE_FOR_BOTH))
-    {
-      gcall *call = gimple_build_call_internal (fn, 2, op_0, op_1);
-      gimple_call_set_lhs (call, lhs);
-      gsi_insert_before (gsi, call, GSI_SAME_STMT);
+  if (!direct_internal_fn_supported_p (fn, TREE_TYPE (op_0), OPTIMIZE_FOR_BOTH))
+    return false;
 
-      gimple_stmt_iterator psi = gsi_for_stmt (phi);
-      remove_phi_node (&psi, /* release_lhs_p */ false);
-    }
+  gcall *call = gimple_build_call_internal (fn, 2, op_0, op_1);
+  gimple_call_set_lhs (call, lhs);
+  gsi_insert_before (gsi, call, GSI_SAME_STMT);
+
+  return true;
 }
 
 /*
@@ -4073,7 +4073,8 @@ match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gassign *stmt)
   tree lhs = gimple_assign_lhs (stmt);
 
   if (gimple_unsigned_integer_sat_add (lhs, ops, NULL))
-    build_saturation_binary_arith_call (gsi, IFN_SAT_ADD, lhs, ops[0], ops[1]);
+    build_saturation_binary_arith_call_and_replace (gsi, IFN_SAT_ADD, lhs,
+                                                   ops[0], ops[1]);
 }
 
 /*
@@ -4115,19 +4116,22 @@ match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gassign *stmt)
  *   =>
  *   _6 = .SAT_ADD (x_5(D), y_6(D)); [tail call]  */
 
-static void
+static bool
 match_saturation_add (gimple_stmt_iterator *gsi, gphi *phi)
 {
   if (gimple_phi_num_args (phi) != 2)
-    return;
+    return false;
 
   tree ops[2];
   tree phi_result = gimple_phi_result (phi);
 
-  if (gimple_unsigned_integer_sat_add (phi_result, ops, NULL)
-      || gimple_signed_integer_sat_add (phi_result, ops, NULL))
-    build_saturation_binary_arith_call (gsi, phi, IFN_SAT_ADD, phi_result,
-                                       ops[0], ops[1]);
+  if (!gimple_unsigned_integer_sat_add (phi_result, ops, NULL)
+      && !gimple_signed_integer_sat_add (phi_result, ops, NULL))
+    return false;
+
+  return build_saturation_binary_arith_call_and_insert (gsi, IFN_SAT_ADD,
+                                                       phi_result, ops[0],
+                                                       ops[1]);
 }
 
 /*
@@ -4145,7 +4149,8 @@ match_unsigned_saturation_sub (gimple_stmt_iterator *gsi, gassign *stmt)
   tree lhs = gimple_assign_lhs (stmt);
 
   if (gimple_unsigned_integer_sat_sub (lhs, ops, NULL))
-    build_saturation_binary_arith_call (gsi, IFN_SAT_SUB, lhs, ops[0], ops[1]);
+    build_saturation_binary_arith_call_and_replace (gsi, IFN_SAT_SUB, lhs,
+                                                   ops[0], ops[1]);
 }
 
 /*
@@ -4164,19 +4169,22 @@ match_unsigned_saturation_sub (gimple_stmt_iterator *gsi, gassign *stmt)
  *  =>
  *  <bb 4> [local count: 1073741824]:
  *  _1 = .SAT_SUB (x_2(D), y_3(D));  */
-static void
+static bool
 match_saturation_sub (gimple_stmt_iterator *gsi, gphi *phi)
 {
   if (gimple_phi_num_args (phi) != 2)
-    return;
+    return false;
 
   tree ops[2];
   tree phi_result = gimple_phi_result (phi);
 
-  if (gimple_unsigned_integer_sat_sub (phi_result, ops, NULL)
-      || gimple_signed_integer_sat_sub (phi_result, ops, NULL))
-    build_saturation_binary_arith_call (gsi, phi, IFN_SAT_SUB, phi_result,
-                                       ops[0], ops[1]);
+  if (!gimple_unsigned_integer_sat_sub (phi_result, ops, NULL)
+      && !gimple_signed_integer_sat_sub (phi_result, ops, NULL))
+    return false;
+
+  return build_saturation_binary_arith_call_and_insert (gsi, IFN_SAT_SUB,
+                                                       phi_result, ops[0],
+                                                       ops[1]);
 }
 
 /*
@@ -4243,29 +4251,30 @@ match_unsigned_saturation_trunc (gimple_stmt_iterator *gsi, gassign *stmt)
  * _6 = .SAT_TRUNC (x_4(D));
  */
 
-static void
+static bool
 match_saturation_trunc (gimple_stmt_iterator *gsi, gphi *phi)
 {
   if (gimple_phi_num_args (phi) != 2)
-    return;
+    return false;
 
   tree ops[1];
   tree phi_result = gimple_phi_result (phi);
   tree type = TREE_TYPE (phi_result);
 
-  if ((gimple_unsigned_integer_sat_trunc (phi_result, ops, NULL)
-      || gimple_signed_integer_sat_trunc (phi_result, ops, NULL))
-      && direct_internal_fn_supported_p (IFN_SAT_TRUNC,
-                                        tree_pair (type, TREE_TYPE (ops[0])),
-                                        OPTIMIZE_FOR_BOTH))
-    {
-      gcall *call = gimple_build_call_internal (IFN_SAT_TRUNC, 1, ops[0]);
-      gimple_call_set_lhs (call, phi_result);
-      gsi_insert_before (gsi, call, GSI_SAME_STMT);
+  if (!gimple_unsigned_integer_sat_trunc (phi_result, ops, NULL)
+      && !gimple_signed_integer_sat_trunc (phi_result, ops, NULL))
+    return false;
 
-      gimple_stmt_iterator psi = gsi_for_stmt (phi);
-      remove_phi_node (&psi, /* release_lhs_p */ false);
-    }
+  if (!direct_internal_fn_supported_p (IFN_SAT_TRUNC,
+                                      tree_pair (type, TREE_TYPE (ops[0])),
+                                      OPTIMIZE_FOR_BOTH))
+    return false;
+
+  gcall *call = gimple_build_call_internal (IFN_SAT_TRUNC, 1, ops[0]);
+  gimple_call_set_lhs (call, phi_result);
+  gsi_insert_before (gsi, call, GSI_SAME_STMT);
+
+  return true;
 }
 
 /* Recognize for unsigned x
@@ -6316,11 +6325,12 @@ math_opts_dom_walker::after_dom_children (basic_block bb)
       gsi_next (&psi_next);
 
       gimple_stmt_iterator gsi = gsi_after_labels (bb);
+      gphi *phi = psi.phi ();
 
-      /* The match_* may remove phi node.  */
-      match_saturation_add (&gsi, psi.phi ());
-      match_saturation_sub (&gsi, psi.phi ());
-      match_saturation_trunc (&gsi, psi.phi ());
+      if (match_saturation_add (&gsi, phi)
+         || match_saturation_sub (&gsi, phi)
+         || match_saturation_trunc (&gsi, phi))
+       remove_phi_node (&psi, /* release_lhs_p */ false);
     }
 
   for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi);)