[gcc r15-959] xtensa: Prepend "(use A0_REG)" to sibling call CALL_INSN_FUNCTION_USAGE instead of emitting it as in

[Max Filippov via Gcc-cvs]

https://gcc.gnu.org/g:be9b3f4375e74b6f10dd15fc563c93f803e91db5

commit r15-959-gbe9b3f4375e74b6f10dd15fc563c93f803e91db5
Author: Takayuki 'January June' Suwa <jjsuwa_sys3...@yahoo.co.jp>
Date:   Fri May 31 19:24:48 2024 +0900

    xtensa: Prepend "(use A0_REG)" to sibling call CALL_INSN_FUNCTION_USAGE 
instead of emitting it as insn at the end of epilogue
    
    No functional changes.
    
    gcc/ChangeLog:
    
            * config/xtensa/xtensa-protos.h (xtensa_expand_call):
            Add the third argument as boolean.
            (xtensa_expand_epilogue): Remove the first argument.
            * config/xtensa/xtensa.cc (xtensa_expand_call):
            Add the third argument "sibcall_p", and modify in order to prepend
            "(use A0_REG)" to CALL_INSN_FUNCTION_USAGE if the argument is true.
            (xtensa_expand_epilogue): Remove the first argument "sibcall_p" and
            its conditional clause.
            * config/xtensa/xtensa.md (call, call_value, sibcall, 
sibcall_value):
            Append a boolean value to the argument of xtensa_expand_call()
            indicating whether it is sibling call or not.
            (epilogue): Remove the boolean argument from 
xtensa_expand_epilogue(),
            and then append emitting "(return)".
            (sibcall_epilogue): Remove the boolean argument from
            xtensa_expand_epilogue().

Diff:
---
 gcc/config/xtensa/xtensa-protos.h |  4 ++--
 gcc/config/xtensa/xtensa.cc       | 16 ++++++++++------
 gcc/config/xtensa/xtensa.md       | 13 +++++++------
 3 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/gcc/config/xtensa/xtensa-protos.h 
b/gcc/config/xtensa/xtensa-protos.h
index 834f15e0e48..77553b0453f 100644
--- a/gcc/config/xtensa/xtensa-protos.h
+++ b/gcc/config/xtensa/xtensa-protos.h
@@ -53,7 +53,7 @@ extern void xtensa_expand_atomic (enum rtx_code, rtx, rtx, 
rtx, bool);
 extern void xtensa_emit_loop_end (rtx_insn *, rtx *);
 extern char *xtensa_emit_branch (bool, rtx *);
 extern char *xtensa_emit_movcc (bool, bool, bool, rtx *);
-extern void xtensa_expand_call (int, rtx *);
+extern void xtensa_expand_call (int, rtx *, bool);
 extern char *xtensa_emit_call (int, rtx *);
 extern char *xtensa_emit_sibcall (int, rtx *);
 extern bool xtensa_tls_referenced_p (rtx);
@@ -76,7 +76,7 @@ extern void xtensa_setup_frame_addresses (void);
 extern int xtensa_debugger_regno (int);
 extern long compute_frame_size (poly_int64);
 extern void xtensa_expand_prologue (void);
-extern void xtensa_expand_epilogue (bool);
+extern void xtensa_expand_epilogue (void);
 extern void xtensa_adjust_reg_alloc_order (void);
 extern enum reg_class xtensa_regno_to_class (int regno);
 extern HOST_WIDE_INT xtensa_initial_elimination_offset (int from, int to);
diff --git a/gcc/config/xtensa/xtensa.cc b/gcc/config/xtensa/xtensa.cc
index 301448c65e2..45dc1be3ff5 100644
--- a/gcc/config/xtensa/xtensa.cc
+++ b/gcc/config/xtensa/xtensa.cc
@@ -2239,7 +2239,7 @@ xtensa_emit_movcc (bool inverted, bool isfp, bool isbool, 
rtx *operands)
 
 
 void
-xtensa_expand_call (int callop, rtx *operands)
+xtensa_expand_call (int callop, rtx *operands, bool sibcall_p)
 {
   rtx call;
   rtx_insn *call_insn;
@@ -2281,6 +2281,14 @@ xtensa_expand_call (int callop, rtx *operands)
       CALL_INSN_FUNCTION_USAGE (call_insn) =
        gen_rtx_EXPR_LIST (Pmode, clob, CALL_INSN_FUNCTION_USAGE (call_insn));
     }
+  else if (sibcall_p)
+    {
+      /* Sibling call requires a return address to the caller, similar to
+        "return" insn.  */
+      rtx use = gen_rtx_USE (VOIDmode, gen_rtx_REG (SImode, A0_REG));
+      CALL_INSN_FUNCTION_USAGE (call_insn) =
+       gen_rtx_EXPR_LIST (Pmode, use, CALL_INSN_FUNCTION_USAGE (call_insn));
+    }
 }
 
 
@@ -3671,7 +3679,7 @@ xtensa_expand_prologue (void)
 }
 
 void
-xtensa_expand_epilogue (bool sibcall_p)
+xtensa_expand_epilogue (void)
 {
   if (!TARGET_WINDOWED_ABI)
     {
@@ -3736,10 +3744,6 @@ xtensa_expand_epilogue (bool sibcall_p)
                                  stack_pointer_rtx,
                                  EH_RETURN_STACKADJ_RTX));
     }
-  if (sibcall_p)
-    emit_use (gen_rtx_REG (SImode, A0_REG));
-  else
-    emit_jump_insn (gen_return ());
 }
 
 void
diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
index 03e816b8a12..ef826b63e44 100644
--- a/gcc/config/xtensa/xtensa.md
+++ b/gcc/config/xtensa/xtensa.md
@@ -2553,7 +2553,7 @@
         (match_operand 1 "" ""))]
   ""
 {
-  xtensa_expand_call (0, operands);
+  xtensa_expand_call (0, operands, false);
   DONE;
 })
 
@@ -2574,7 +2574,7 @@
              (match_operand 2 "" "")))]
   ""
 {
-  xtensa_expand_call (1, operands);
+  xtensa_expand_call (1, operands, false);
   DONE;
 })
 
@@ -2595,7 +2595,7 @@
         (match_operand 1 "" ""))]
   "!TARGET_WINDOWED_ABI"
 {
-  xtensa_expand_call (0, operands);
+  xtensa_expand_call (0, operands, true);
   DONE;
 })
 
@@ -2616,7 +2616,7 @@
              (match_operand 2 "" "")))]
   "!TARGET_WINDOWED_ABI"
 {
-  xtensa_expand_call (1, operands);
+  xtensa_expand_call (1, operands, true);
   DONE;
 })
 
@@ -2723,7 +2723,8 @@
   [(return)]
   ""
 {
-  xtensa_expand_epilogue (false);
+  xtensa_expand_epilogue ();
+  emit_jump_insn (gen_return ());
   DONE;
 })
 
@@ -2731,7 +2732,7 @@
   [(return)]
   "!TARGET_WINDOWED_ABI"
 {
-  xtensa_expand_epilogue (true);
+  xtensa_expand_epilogue ();
   DONE;
 })