CALL_INSN may not be a real function call.

Use "used" flag for CALL_INSN to indicate it's a fake call. If it's a
fake call, it won't have its own function stack.

gcc/ChangeLog

	PR target/82735
	* df-scan.c (df_get_call_refs): When call_insn is a fake call,
	it won't use stack pointer reg.
	* final.c (leaf_function_p): When call_insn is a fake call, it
	won't affect caller as a leaf function.
	* reg-stack.c (callee_clobbers_any_stack_reg): New.
	(subst_stack_regs): When call_insn doesn't clobber any stack
	reg, don't clear the arguments.
	* rtl.c (shallow_copy_rtx): Don't clear flag used when orig is
	a insn.
	* shrink-wrap.c (requires_stack_frame_p): No need for stack
	frame for a fake call.
	* rtl.h (FAKE_CALL_P): New macro.

1 files changed, 4 insertions, 2 deletions

diff --git a/gcc/rtl.c b/gcc/rtl.c
index b0ba1ff..aaee882 100644
--- a/gcc/rtl.c
+++ b/gcc/rtl.c
@@ -395,8 +395,10 @@ shallow_copy_rtx (const_rtx orig MEM_STAT_DECL)
     case SCRATCH:
       break;
     default:
-      /* For all other RTXes clear the used flag on the copy.  */
-      RTX_FLAG (copy, used) = 0;
+      /* For all other RTXes clear the used flag on the copy.
+	 CALL_INSN use "used" flag to indicate it's a fake call.  */
+      if (!INSN_P (orig))
+	RTX_FLAG (copy, used) = 0;
       break;
     }
   return copy;