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-rw-r--r--gcc/tree-cfgcleanup.cc24
1 files changed, 24 insertions, 0 deletions
diff --git a/gcc/tree-cfgcleanup.cc b/gcc/tree-cfgcleanup.cc
index a34a51e..5aaa18d 100644
--- a/gcc/tree-cfgcleanup.cc
+++ b/gcc/tree-cfgcleanup.cc
@@ -47,6 +47,7 @@ along with GCC; see the file COPYING3. If not see
#include "tree-into-ssa.h"
#include "tree-cfgcleanup.h"
#include "gimple-pretty-print.h"
+#include "target.h"
/* The set of blocks in that at least one of the following changes happened:
@@ -1569,6 +1570,29 @@ execute_cleanup_cfg_post_optimizing (void)
cleanup_dead_labels ();
if (group_case_labels ())
todo |= TODO_cleanup_cfg;
+
+ basic_block bb = single_succ (ENTRY_BLOCK_PTR_FOR_FN (cfun));
+ gimple_stmt_iterator gsi = gsi_start_nondebug_after_labels_bb (bb);
+ /* If the first (and only) bb and the only non debug
+ statement is __builtin_unreachable call, then replace it with a trap
+ so the function is at least one instruction in size. */
+ if (!gsi_end_p (gsi)
+ && gimple_call_builtin_p (gsi_stmt (gsi), BUILT_IN_UNREACHABLE))
+ {
+ if (targetm.have_trap ())
+ {
+ gimple_call_set_fndecl (gsi_stmt (gsi), builtin_decl_implicit (BUILT_IN_UNREACHABLE_TRAP));
+ update_stmt (gsi_stmt (gsi));
+ }
+ /* If the target does not have a trap, convert it into an infinite loop. */
+ else
+ {
+ gsi_remove (&gsi, true);
+ make_single_succ_edge (bb, bb, EDGE_FALLTHRU);
+ fix_loop_structure (NULL);
+ }
+ }
+
if ((flag_compare_debug_opt || flag_compare_debug)
&& flag_dump_final_insns)
{