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File _service:tar_scm:0082-Revert-Backport-tree-optimization-102880-make-PHI-OP.patch of Package gcc (Revision ca747df1b2b3cd18598aa02a311a4f94)

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From 717782ec36469eb81650b07e8b5536281a59993d Mon Sep 17 00:00:00 2001
From: zhongyunde <zhongyunde@huawei.com>
Date: Tue, 29 Nov 2022 22:12:29 +0800
Subject: [PATCH 34/35] Revert "[Backport] tree-optimization/102880 - make
 PHI-OPT recognize more CFGs"

This reverts commit 77398954ce517aa011b7a254c7aa2858521b2093.
---
 gcc/testsuite/gcc.dg/tree-ssa/phi-opt-26.c | 31 ---------
 gcc/tree-ssa-phiopt.c                      | 73 +++++++++-------------
 2 files changed, 29 insertions(+), 75 deletions(-)
 delete mode 100644 gcc/testsuite/gcc.dg/tree-ssa/phi-opt-26.c

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-26.c b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-26.c
deleted file mode 100644
index 21aa66e38..000000000
--- a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-26.c
+++ /dev/null
@@ -1,31 +0,0 @@
-/* { dg-do compile } */
-/* { dg-options "-O -fgimple -fdump-tree-phiopt1" } */
-
-int __GIMPLE (ssa,startwith("phiopt"))
-foo (int a, int b, int flag)
-{
-  int res;
-
-  __BB(2):
-  if (flag_2(D) != 0)
-    goto __BB6;
-  else
-    goto __BB4;
-
-  __BB(4):
-  if (a_3(D) > b_4(D))
-    goto __BB7;
-  else
-    goto __BB6;
-
-  __BB(6):
-  goto __BB7;
-
-  __BB(7):
-  res_1 = __PHI (__BB4: a_3(D), __BB6: b_4(D));
-  return res_1;
-}
-
-/* We should be able to detect MAX despite the extra edge into
-   the middle BB.  */
-/* { dg-final { scan-tree-dump "MAX" "phiopt1" } } */
diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index 079d29e74..21ac08145 100644
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -219,6 +219,7 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads, bool early_p)
 
       /* If either bb1's succ or bb2 or bb2's succ is non NULL.  */
       if (EDGE_COUNT (bb1->succs) == 0
+          || bb2 == NULL
 	  || EDGE_COUNT (bb2->succs) == 0)
         continue;
 
@@ -278,14 +279,14 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads, bool early_p)
 	  || (e1->flags & EDGE_FALLTHRU) == 0)
         continue;
 
+      /* Also make sure that bb1 only have one predecessor and that it
+	 is bb.  */
+      if (!single_pred_p (bb1)
+          || single_pred (bb1) != bb)
+	continue;
+
       if (do_store_elim)
 	{
-	  /* Also make sure that bb1 only have one predecessor and that it
-	     is bb.  */
-	  if (!single_pred_p (bb1)
-	      || single_pred (bb1) != bb)
-	    continue;
-
 	  /* bb1 is the middle block, bb2 the join block, bb the split block,
 	     e1 the fallthrough edge from bb1 to bb2.  We can't do the
 	     optimization if the join block has more than two predecessors.  */
@@ -330,11 +331,10 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads, bool early_p)
 	     node.  */
 	  gcc_assert (arg0 != NULL_TREE && arg1 != NULL_TREE);
 
-	  gphi *newphi;
-	  if (single_pred_p (bb1)
-	      && (newphi = factor_out_conditional_conversion (e1, e2, phi,
-							      arg0, arg1,
-							      cond_stmt)))
+	  gphi *newphi = factor_out_conditional_conversion (e1, e2, phi,
+							    arg0, arg1,
+							    cond_stmt);
+	  if (newphi != NULL)
 	    {
 	      phi = newphi;
 	      /* factor_out_conditional_conversion may create a new PHI in
@@ -355,14 +355,12 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool do_hoist_loads, bool early_p)
 	  else if (abs_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
 	    cfgchanged = true;
 	  else if (!early_p
-		   && single_pred_p (bb1)
 		   && cond_removal_in_builtin_zero_pattern (bb, bb1, e1, e2,
 							    phi, arg0, arg1))
 	    cfgchanged = true;
 	  else if (minmax_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
 	    cfgchanged = true;
-	  else if (single_pred_p (bb1)
-		   && spaceship_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
+	  else if (spaceship_replacement (bb, bb1, e1, e2, phi, arg0, arg1))
 	    cfgchanged = true;
 	}
     }
@@ -393,41 +391,35 @@ replace_phi_edge_with_variable (basic_block cond_block,
 				edge e, gphi *phi, tree new_tree)
 {
   basic_block bb = gimple_bb (phi);
+  basic_block block_to_remove;
   gimple_stmt_iterator gsi;
 
   /* Change the PHI argument to new.  */
   SET_USE (PHI_ARG_DEF_PTR (phi, e->dest_idx), new_tree);
 
   /* Remove the empty basic block.  */
-  edge edge_to_remove;
   if (EDGE_SUCC (cond_block, 0)->dest == bb)
-    edge_to_remove = EDGE_SUCC (cond_block, 1);
-  else
-    edge_to_remove = EDGE_SUCC (cond_block, 0);
-  if (EDGE_COUNT (edge_to_remove->dest->preds) == 1)
     {
-      e->flags |= EDGE_FALLTHRU;
-      e->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE);
-      e->probability = profile_probability::always ();
-      delete_basic_block (edge_to_remove->dest);
-
-      /* Eliminate the COND_EXPR at the end of COND_BLOCK.  */
-      gsi = gsi_last_bb (cond_block);
-      gsi_remove (&gsi, true);
+      EDGE_SUCC (cond_block, 0)->flags |= EDGE_FALLTHRU;
+      EDGE_SUCC (cond_block, 0)->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE);
+      EDGE_SUCC (cond_block, 0)->probability = profile_probability::always ();
+
+      block_to_remove = EDGE_SUCC (cond_block, 1)->dest;
     }
   else
     {
-      /* If there are other edges into the middle block make
-	 CFG cleanup deal with the edge removal to avoid
-	 updating dominators here in a non-trivial way.  */
-      gcond *cond = as_a <gcond *> (last_stmt (cond_block));
-      if (edge_to_remove->flags & EDGE_TRUE_VALUE)
-	gimple_cond_make_false (cond);
-      else
-	gimple_cond_make_true (cond);
+      EDGE_SUCC (cond_block, 1)->flags |= EDGE_FALLTHRU;
+      EDGE_SUCC (cond_block, 1)->flags
+	&= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE);
+      EDGE_SUCC (cond_block, 1)->probability = profile_probability::always ();
+
+      block_to_remove = EDGE_SUCC (cond_block, 0)->dest;
     }
+  delete_basic_block (block_to_remove);
 
-  statistics_counter_event (cfun, "Replace PHI with variable", 1);
+  /* Eliminate the COND_EXPR at the end of COND_BLOCK.  */
+  gsi = gsi_last_bb (cond_block);
+  gsi_remove (&gsi, true);
 
   if (dump_file && (dump_flags & TDF_DETAILS))
     fprintf (dump_file,
@@ -854,9 +846,6 @@ match_simplify_replacement (basic_block cond_bb, basic_block middle_bb,
      allow it and move it once the transformation is done. */
   if (!empty_block_p (middle_bb))
     {
-      if (!single_pred_p (middle_bb))
-	return false;
-
       stmt_to_move = last_and_only_stmt (middle_bb);
       if (!stmt_to_move)
 	return false;
@@ -1236,11 +1225,6 @@ value_replacement (basic_block cond_bb, basic_block middle_bb,
 	}
       else
 	{
-	  if (!single_pred_p (middle_bb))
-	    return 0;
-	  statistics_counter_event (cfun, "Replace PHI with "
-				    "variable/value_replacement", 1);
-
 	  /* Replace the PHI arguments with arg. */
 	  SET_PHI_ARG_DEF (phi, e0->dest_idx, arg);
 	  SET_PHI_ARG_DEF (phi, e1->dest_idx, arg);
@@ -1255,6 +1239,7 @@ value_replacement (basic_block cond_bb, basic_block middle_bb,
             }
           return 1;
 	}
+
     }
 
   /* Now optimize (x != 0) ? x + y : y to just x + y.  */
-- 
2.27.0.windows.1