https://gcc.gnu.org/g:2291739ec432abc01c7afc5a07443c575539316a

commit r15-4177-g2291739ec432abc01c7afc5a07443c575539316a
Author: Pan Li <pan2...@intel.com>
Date:   Tue Oct 8 11:06:23 2024 +0800

    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...@intel.com>

Diff:
---
 gcc/tree-ssa-math-opts.cc | 102 +++++++++++++++++++++++++---------------------
 1 file changed, 56 insertions(+), 46 deletions(-)

diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index dad8428d3d8a..f9ccdf41d67f 100644
--- 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);)

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