Some of the cfg fixups in pro_and_epilogue for sibcalls were dependent on
"optimize".
Make them check cfun->tail_call_marked instead to handle the -O0 musttail
case. This fixes the musttail test cases on arm targets.
gcc/ChangeLog:
PR target/115255
* function.cc (thread_prologue_and_epilogue_insns): Check
cfun->tail_call_marked for sibcalls too.
(rest_of_handle_thread_prologue_and_epilogue): Dito.
---
gcc/function.cc | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/gcc/function.cc b/gcc/function.cc
index 4edd4da12474..a6f6de349420 100644
--- a/gcc/function.cc
+++ b/gcc/function.cc
@@ -2231,6 +2231,7 @@ use_register_for_decl (const_tree decl)
/* We don't set DECL_IGNORED_P for the function_result_decl. */
if (optimize)
return true;
+ /* Needed for [[musttail]] which can operate even at -O0 */
if (cfun->tail_call_marked)
return true;
/* We don't set DECL_REGISTER for the function_result_decl. */
@@ -6259,8 +6260,11 @@ thread_prologue_and_epilogue_insns (void)
}
/* Threading the prologue and epilogue changes the artificial refs in the
- entry and exit blocks, and may invalidate DF info for tail calls. */
+ entry and exit blocks, and may invalidate DF info for tail calls.
+ This is also needed for [[musttail]] conversion even when not
+ optimizing. */
if (optimize
+ || cfun->tail_call_marked
|| flag_optimize_sibling_calls
|| flag_ipa_icf_functions
|| in_lto_p)
@@ -6557,7 +6561,7 @@ rest_of_handle_thread_prologue_and_epilogue (function
*fun)
{
/* prepare_shrink_wrap is sensitive to the block structure of the control
flow graph, so clean it up first. */
- if (optimize)
+ if (cfun->tail_call_marked || optimize)
cleanup_cfg (0);
/* On some machines, the prologue and epilogue code, or parts thereof,
--
2.45.2
