diff mbox series

tree-optimization/111397 - missed copy propagation involving abnormal dest

Message ID 20230913082312.2E6193858296@sourceware.org
State Accepted
Headers
Series tree-optimization/111397 - missed copy propagation involving abnormal dest |

Checks

Context Check Description
snail/gcc-patch-check success Github commit url

Commit Message

Richard Biener Sept. 13, 2023, 8:22 a.m. UTC 
  The following extends the previous enhancement to copy propagation
involving abnormals.  We can easily replace abnormal uses by not
abnormal uses and only need to preserve the abnormals in PHI arguments
flowing in from abnormal edges.  This changes the may_propagate_copy
argument indicating we are not propagating into a PHI node to indicate
whether we know we are not propagating into a PHI argument from an
abnormal PHI instead.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

	PR tree-optimization/111397
	* tree-ssa-propagate.cc (may_propagate_copy): Change optional
	argument to specify whether the PHI destination doesn't flow in
	from an abnormal PHI.
	(propagate_value): Adjust.
	* tree-ssa-forwprop.cc (pass_forwprop::execute): Indicate abnormal
	PHI dest.
	* tree-ssa-sccvn.cc (eliminate_dom_walker::before_dom_children):
	Likewise.
	(process_bb): Likewise.

	* gcc.dg/uninit-pr111397.c: New testcase.
---
 gcc/testsuite/gcc.dg/uninit-pr111397.c | 15 +++++++++++++++
 gcc/tree-ssa-forwprop.cc               |  2 +-
 gcc/tree-ssa-propagate.cc              | 20 +++++++++++++-------
 gcc/tree-ssa-sccvn.cc                  |  5 +++--
 4 files changed, 32 insertions(+), 10 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/uninit-pr111397.c
diff mbox series

Patch

diff --git a/gcc/testsuite/gcc.dg/uninit-pr111397.c b/gcc/testsuite/gcc.dg/uninit-pr111397.c
new file mode 100644
index 00000000000..ec12f9d642a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/uninit-pr111397.c
@@ -0,0 +1,15 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wuninitialized" } */
+
+int globalVar = 1;
+int __attribute__ ((__returns_twice__)) test_setjmpex(void *context);
+
+void testfn()
+{
+  int localVar = globalVar;
+  while (!localVar) {
+      test_setjmpex(__builtin_frame_address (0)); // { dg-bogus "uninitialized" }
+      if (globalVar)
+	break;
+  }
+}
diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
index 047f9237dd4..94ca47a9726 100644
--- a/gcc/tree-ssa-forwprop.cc
+++ b/gcc/tree-ssa-forwprop.cc
@@ -4070,7 +4070,7 @@  pass_forwprop::execute (function *fun)
 	      continue;
 	    tree val = fwprop_ssa_val (arg);
 	    if (val != arg
-		&& may_propagate_copy (arg, val))
+		&& may_propagate_copy (arg, val, !(e->flags & EDGE_ABNORMAL)))
 	      propagate_value (use_p, val);
 	  }
 
diff --git a/gcc/tree-ssa-propagate.cc b/gcc/tree-ssa-propagate.cc
index cb68b419b8c..a29c49328ad 100644
--- a/gcc/tree-ssa-propagate.cc
+++ b/gcc/tree-ssa-propagate.cc
@@ -1032,11 +1032,12 @@  substitute_and_fold_engine::substitute_and_fold (basic_block block)
 
 
 /* Return true if we may propagate ORIG into DEST, false otherwise.
-   If DEST_NOT_PHI_ARG_P is true then assume the propagation does
-   not happen into a PHI argument which relaxes some constraints.  */
+   If DEST_NOT_ABNORMAL_PHI_EDGE_P is true then assume the propagation does
+   not happen into a PHI argument which flows in from an abnormal edge
+   which relaxes some constraints.  */
 
 bool
-may_propagate_copy (tree dest, tree orig, bool dest_not_phi_arg_p)
+may_propagate_copy (tree dest, tree orig, bool dest_not_abnormal_phi_edge_p)
 {
   tree type_d = TREE_TYPE (dest);
   tree type_o = TREE_TYPE (orig);
@@ -1056,9 +1057,9 @@  may_propagate_copy (tree dest, tree orig, bool dest_not_phi_arg_p)
 	   && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig))
     return false;
   /* Similarly if DEST flows in from an abnormal edge then the copy cannot be
-     propagated.  If we know we do not propagate into a PHI argument this
+     propagated.  If we know we do not propagate into such a PHI argument this
      does not apply.  */
-  else if (!dest_not_phi_arg_p
+  else if (!dest_not_abnormal_phi_edge_p
 	   && TREE_CODE (dest) == SSA_NAME
 	   && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (dest))
     return false;
@@ -1162,8 +1163,13 @@  void
 propagate_value (use_operand_p op_p, tree val)
 {
   if (flag_checking)
-    gcc_assert (may_propagate_copy (USE_FROM_PTR (op_p), val,
-				    !is_a <gphi *> (USE_STMT (op_p))));
+    {
+      bool ab = (is_a <gphi *> (USE_STMT (op_p))
+		 && (gimple_phi_arg_edge (as_a <gphi *> (USE_STMT (op_p)),
+					  PHI_ARG_INDEX_FROM_USE (op_p))
+		     ->flags & EDGE_ABNORMAL));
+      gcc_assert (may_propagate_copy (USE_FROM_PTR (op_p), val, !ab));
+    }
   replace_exp (op_p, val);
 }
 
diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc
index d9487be302b..1eaf5f6a363 100644
--- a/gcc/tree-ssa-sccvn.cc
+++ b/gcc/tree-ssa-sccvn.cc
@@ -7399,7 +7399,8 @@  eliminate_dom_walker::before_dom_children (basic_block b)
 	      || virtual_operand_p (arg))
 	    continue;
 	  tree sprime = eliminate_avail (b, arg);
-	  if (sprime && may_propagate_copy (arg, sprime))
+	  if (sprime && may_propagate_copy (arg, sprime,
+					    !(e->flags & EDGE_ABNORMAL)))
 	    propagate_value (use_p, sprime);
 	}
 
@@ -8192,7 +8193,7 @@  process_bb (rpo_elim &avail, basic_block bb,
 					    arg);
 	  if (sprime
 	      && sprime != arg
-	      && may_propagate_copy (arg, sprime))
+	      && may_propagate_copy (arg, sprime, !(e->flags & EDGE_ABNORMAL)))
 	    propagate_value (use_p, sprime);
 	}