From 5cb8610d3a8f8849a4bb6a0f81a2934484d6a15a Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Wed, 15 Nov 2023 12:24:46 +0100
Subject: tree-optimization/112282 - wrong-code with ifcvt hoisting

The following avoids hoisting of invariants from conditionally
executed parts of an if-converted loop.  That now makes a difference
since we perform bitfield lowering even when we do not actually
if-convert the loop.  if-conversion deals with resetting flow-sensitive
info when necessary already.

	PR tree-optimization/112282
	* tree-if-conv.cc (ifcvt_hoist_invariants): Only hoist from
	the loop header.

	* gcc.dg/torture/pr112282.c: New testcase.
---
 gcc/tree-if-conv.cc | 44 +++++++++++++++++++++-----------------------
 1 file changed, 21 insertions(+), 23 deletions(-)

(limited to 'gcc/tree-if-conv.cc')

diff --git a/gcc/tree-if-conv.cc b/gcc/tree-if-conv.cc
index 0190cf2..0bde281 100644
--- a/gcc/tree-if-conv.cc
+++ b/gcc/tree-if-conv.cc
@@ -3468,30 +3468,28 @@ ifcvt_can_hoist (class loop *loop, edge pe, gimple *stmt)
 static void
 ifcvt_hoist_invariants (class loop *loop, edge pe)
 {
+  /* Only hoist from the now unconditionally executed part of the loop.  */
+  basic_block bb = loop->header;
   gimple_stmt_iterator hoist_gsi = {};
-  unsigned int num_blocks = loop->num_nodes;
-  basic_block *body = get_loop_body (loop);
-  for (unsigned int i = 0; i < num_blocks; ++i)
-    for (gimple_stmt_iterator gsi = gsi_start_bb (body[i]); !gsi_end_p (gsi);)
-      {
-	gimple *stmt = gsi_stmt (gsi);
-	if (ifcvt_can_hoist (loop, pe, stmt))
-	  {
-	    /* Once we've hoisted one statement, insert other statements
-	       after it.  */
-	    gsi_remove (&gsi, false);
-	    if (hoist_gsi.ptr)
-	      gsi_insert_after (&hoist_gsi, stmt, GSI_NEW_STMT);
-	    else
-	      {
-		gsi_insert_on_edge_immediate (pe, stmt);
-		hoist_gsi = gsi_for_stmt (stmt);
-	      }
-	    continue;
-	  }
-	gsi_next (&gsi);
-      }
-  free (body);
+  for (gimple_stmt_iterator gsi = gsi_start_bb (bb); !gsi_end_p (gsi);)
+    {
+      gimple *stmt = gsi_stmt (gsi);
+      if (ifcvt_can_hoist (loop, pe, stmt))
+	{
+	  /* Once we've hoisted one statement, insert other statements
+	     after it.  */
+	  gsi_remove (&gsi, false);
+	  if (hoist_gsi.ptr)
+	    gsi_insert_after (&hoist_gsi, stmt, GSI_NEW_STMT);
+	  else
+	    {
+	      gsi_insert_on_edge_immediate (pe, stmt);
+	      hoist_gsi = gsi_for_stmt (stmt);
+	    }
+	  continue;
+	}
+      gsi_next (&gsi);
+    }
 }
 
 /* Returns the DECL_FIELD_BIT_OFFSET of the bitfield accesse in stmt iff its
-- 
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