[PATCH] Fix some gimple_ctrl_altering_p mistakes

[PATCH] Fix some gimple_ctrl_altering_p mistakes

[Richard Biener]

CFG cleanup resets the control altering flag for noreturn functions
when they are ECF_LEAF (like __builtin_unreachable ()).  The
.ABNORMAL_DISPATCHER call built during CFG construction is not
marked as control altering.  Several passes inserting traps or
unreachables fail to set the flag.  And more.

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

	PR middle-end/106870
	* gimple-harden-conditionals.cc (insert_check_and_trap):
	Set the control-altering flag on the built IFN_TRAP.
	* gimple.cc (gimple_build_builtin_unreachable): Likewise.
	* tree-cfg.cc (handle_abnormal_edges): Set the control-altering
	flag on the .ABNORMAL_DISPATCHER call.
	* tree-cfgcleanup.cc (cleanup_call_ctrl_altering_flag): Avoid
	resetting the control altering flag for ECF_NORETURN calls.
	(cleanup_control_flow_bb): Set the control altering flag on
	discovered noreturn calls.
	* symtab-thunks.cc (expand_thunk): Set the control altering
	flag for the noreturn tailcall case.
	* tree-eh.cc (lower_resx): Likewisw for trap and unwind_resume
	calls.
---
 gcc/gimple-harden-conditionals.cc |  1 +
 gcc/gimple.cc                     |  1 +
 gcc/symtab-thunks.cc              |  1 +
 gcc/tree-cfg.cc                   |  3 ++-
 gcc/tree-cfgcleanup.cc            | 11 ++++++++---
 gcc/tree-eh.cc                    |  4 +++-
 6 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/gcc/gimple-harden-conditionals.cc b/gcc/gimple-harden-conditionals.cc
index 4ca6776fca7..1b3dd563baa 100644
--- a/gcc/gimple-harden-conditionals.cc
+++ b/gcc/gimple-harden-conditionals.cc
@@ -238,6 +238,7 @@ insert_check_and_trap (location_t loc, gimple_stmt_iterator *gsip,
 
   gimple_stmt_iterator gsit = gsi_after_labels (trp);
   gcall *trap = gimple_build_call (builtin_decl_explicit (BUILT_IN_TRAP), 0);
+  gimple_call_set_ctrl_altering (trap, true);
   gimple_set_location (trap, loc);
   gsi_insert_before (&gsit, trap, GSI_SAME_STMT);
 
diff --git a/gcc/gimple.cc b/gcc/gimple.cc
index cd5ad0c718b..4d45311b45c 100644
--- a/gcc/gimple.cc
+++ b/gcc/gimple.cc
@@ -440,6 +440,7 @@ gimple_build_builtin_unreachable (location_t loc)
       gcc_checking_assert (data == NULL_TREE);
       g = gimple_build_call_internal (IFN_TRAP, 0);
     }
+  gimple_call_set_ctrl_altering (g, true);
   gimple_set_location (g, loc);
   return g;
 }
diff --git a/gcc/symtab-thunks.cc b/gcc/symtab-thunks.cc
index b0439702230..bd50c689761 100644
--- a/gcc/symtab-thunks.cc
+++ b/gcc/symtab-thunks.cc
@@ -635,6 +635,7 @@ expand_thunk (cgraph_node *node, bool output_asm_thunks,
 	}
       else
 	{
+	  gimple_call_set_ctrl_altering (call, true);
 	  gimple_call_set_tail (call, true);
 	  cfun->tail_call_marked = true;
 	  remove_edge (single_succ_edge (bb));
diff --git a/gcc/tree-cfg.cc b/gcc/tree-cfg.cc
index 3e2d0adf4a2..a939a11d8bb 100644
--- a/gcc/tree-cfg.cc
+++ b/gcc/tree-cfg.cc
@@ -821,8 +821,9 @@ handle_abnormal_edges (basic_block *dispatcher_bbs, basic_block for_bb,
       else
 	{
 	  tree arg = inner ? boolean_true_node : boolean_false_node;
-	  gimple *g = gimple_build_call_internal (IFN_ABNORMAL_DISPATCHER,
+	  gcall *g = gimple_build_call_internal (IFN_ABNORMAL_DISPATCHER,
 						 1, arg);
+	  gimple_call_set_ctrl_altering (g, true);
 	  gimple_stmt_iterator gsi = gsi_after_labels (*dispatcher);
 	  gsi_insert_after (&gsi, g, GSI_NEW_STMT);
 
diff --git a/gcc/tree-cfgcleanup.cc b/gcc/tree-cfgcleanup.cc
index 3535a7e28a4..b4869aee78d 100644
--- a/gcc/tree-cfgcleanup.cc
+++ b/gcc/tree-cfgcleanup.cc
@@ -220,9 +220,10 @@ cleanup_call_ctrl_altering_flag (basic_block bb, gimple *bb_end)
     return;
 
   int flags = gimple_call_flags (bb_end);
-  if (((flags & (ECF_CONST | ECF_PURE))
-       && !(flags & ECF_LOOPING_CONST_OR_PURE))
-      || (flags & ECF_LEAF))
+  if (!(flags & ECF_NORETURN)
+      && (((flags & (ECF_CONST | ECF_PURE))
+	   && !(flags & ECF_LOOPING_CONST_OR_PURE))
+	  || (flags & ECF_LEAF)))
     gimple_call_set_ctrl_altering (bb_end, false);
   else
     {
@@ -328,6 +329,10 @@ cleanup_control_flow_bb (basic_block bb)
 	gsi_remove (&gsi, true);
       if (remove_fallthru_edge (bb->succs))
 	retval = true;
+      tree lhs = gimple_call_lhs (stmt);
+      if (!lhs
+	  || !should_remove_lhs_p (lhs))
+	gimple_call_set_ctrl_altering (stmt, true);
     }
 
   return retval;
diff --git a/gcc/tree-eh.cc b/gcc/tree-eh.cc
index 076ecd3ec9a..ae8fa21d9a3 100644
--- a/gcc/tree-eh.cc
+++ b/gcc/tree-eh.cc
@@ -3321,7 +3321,7 @@ lower_resx (basic_block bb, gresx *stmt,
   int lp_nr;
   eh_region src_r, dst_r;
   gimple_stmt_iterator gsi;
-  gimple *x;
+  gcall *x;
   tree fn, src_nr;
   bool ret = false;
 
@@ -3346,6 +3346,7 @@ lower_resx (basic_block bb, gresx *stmt,
 
       fn = builtin_decl_implicit (BUILT_IN_TRAP);
       x = gimple_build_call (fn, 0);
+      gimple_call_set_ctrl_altering (x, true);
       gsi_insert_before (&gsi, x, GSI_SAME_STMT);
 
       while (EDGE_COUNT (bb->succs) > 0)
@@ -3463,6 +3464,7 @@ lower_resx (basic_block bb, gresx *stmt,
 
 	  fn = builtin_decl_implicit (BUILT_IN_UNWIND_RESUME);
 	  x = gimple_build_call (fn, 1, var);
+	  gimple_call_set_ctrl_altering (x, true);
 	  gsi_insert_before (&gsi, x, GSI_SAME_STMT);
 	}
 
-- 
2.35.3