From: Jin Ma <jinma@linux.alibaba.com>
Date: Fri, 3 Feb 2023 09:42:59 +0000 (+0800)
Subject: RISC-V: Change the generation mode of ADJUST_SP_RTX from gen_insn to gen_SET.
X-Git-Tag: basepoints/gcc-14~1254
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=52009fa79cdb497b9e410bb4a5b54960a4a44463;p=thirdparty%2Fgcc.git

RISC-V: Change the generation mode of ADJUST_SP_RTX from gen_insn to gen_SET.

The gen_insn method is used to generate ADJUST_SP_RTX here, which has certain
potential risks:

When the architecture adds pre-processing to `define_insn "adddi3"`, such as
`define_expend "adddi3"`, the gen_expand will be automatically called here,
causing the patern to emit directly, which will cause insn to enter REG_NOTE
for `DWARF` instead of patern.

The following error REG_NOTE occurred:
error: invalid rtl sharing found in the insn:
(insn 19 3 20 2 (parallel [
        ...
        ])
    (expr_list:REG_CFA_ADJUST_CFA
        (insn 18 0 0 (set (reg/f:DI 2 sp)
            (plus:DI (reg/f:DI 2 sp)
                (const_int -16 [0xfffffffffffffff0]))) -1
        (nil))))

In fact, the correct one should be the following:
(insn 19 3 20 2 (parallel [
        ...
        ])
    (expr_list:REG_CFA_ADJUST_CFA
        (set (reg/f:DI 2 sp)
            (plus:DI (reg/f:DI 2 sp)
                (const_int -16 [0xfffffffffffffff0])))))

Following the treatment of arm or other architectures, it is more reasonable to
use gen_SET here.

gcc/ChangeLog:

	* config/riscv/riscv.cc (riscv_adjust_libcall_cfi_prologue): Change
	gen_add3_insn to gen_rtx_SET.
	(riscv_adjust_libcall_cfi_epilogue): Likewise.
---

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index a282c7c6494e..de3e1f903c79 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -5082,8 +5082,9 @@ riscv_adjust_libcall_cfi_prologue ()
       }
 
   /* Debug info for adjust sp.  */
-  adjust_sp_rtx = gen_add3_insn (stack_pointer_rtx,
-				 stack_pointer_rtx, GEN_INT (-saved_size));
+  adjust_sp_rtx =
+    gen_rtx_SET (stack_pointer_rtx,
+		 gen_rtx_PLUS (GET_MODE(stack_pointer_rtx), stack_pointer_rtx, GEN_INT (-saved_size)));
   dwarf = alloc_reg_note (REG_CFA_ADJUST_CFA, adjust_sp_rtx,
 			  dwarf);
   return dwarf;
@@ -5204,8 +5205,9 @@ riscv_adjust_libcall_cfi_epilogue ()
   int saved_size = cfun->machine->frame.save_libcall_adjustment;
 
   /* Debug info for adjust sp.  */
-  adjust_sp_rtx = gen_add3_insn (stack_pointer_rtx,
-				 stack_pointer_rtx, GEN_INT (saved_size));
+  adjust_sp_rtx =
+    gen_rtx_SET (stack_pointer_rtx,
+		 gen_rtx_PLUS (GET_MODE(stack_pointer_rtx), stack_pointer_rtx, GEN_INT (saved_size)));
   dwarf = alloc_reg_note (REG_CFA_ADJUST_CFA, adjust_sp_rtx,
 			  dwarf);