[gcc r14-4511] THead: Fix missing CFI directives for th.sdd in prologue.

[Jeff Law]

https://gcc.gnu.org/g:578aa2f80056175b902671b30cc77e38945e3ba4

commit r14-4511-g578aa2f80056175b902671b30cc77e38945e3ba4
Author: Xianmiao Qu <cooper.qu@linux.alibaba.com>
Date:   Mon Oct 9 07:24:39 2023 -0600

    THead: Fix missing CFI directives for th.sdd in prologue.
    
    When generating CFI directives for the store-pair instruction,
    if we add two parallel REG_FRAME_RELATED_EXPR expr_lists like
      (expr_list:REG_FRAME_RELATED_EXPR (set (mem/c:DI (plus:DI (reg/f:DI 2 sp)
        (const_int 8 [0x8])) [1  S8 A64])
        (reg:DI 1 ra))
      (expr_list:REG_FRAME_RELATED_EXPR (set (mem/c:DI (reg/f:DI 2 sp) [1  S8 A64])
        (reg:DI 8 s0))
    only the first expr_list will be recognized by dwarf2out_frame_debug
    funciton. So, here we generate a SEQUENCE expression of REG_FRAME_RELATED_EXPR,
    which includes two sub-expressions of RTX_FRAME_RELATED_P. Then the
    dwarf2out_frame_debug_expr function will iterate through all the sub-expressions
    and generate the corresponding CFI directives.
    
    gcc/
            * config/riscv/thead.cc (th_mempair_save_regs): Fix missing CFI
            directives for store-pair instruction.
    
    gcc/testsuite/
            * gcc.target/riscv/xtheadmempair-4.c: New test.

Diff:
---
 gcc/config/riscv/thead.cc                        | 11 +++++----
 gcc/testsuite/gcc.target/riscv/xtheadmempair-4.c | 29 ++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/gcc/config/riscv/thead.cc b/gcc/config/riscv/thead.cc
index 507c912bc39..be0cd7c1276 100644
--- a/gcc/config/riscv/thead.cc
+++ b/gcc/config/riscv/thead.cc
@@ -366,14 +366,15 @@ th_mempair_save_regs (rtx operands[4])
 {
   rtx set1 = gen_rtx_SET (operands[0], operands[1]);
   rtx set2 = gen_rtx_SET (operands[2], operands[3]);
+  rtx dwarf = gen_rtx_SEQUENCE (VOIDmode, rtvec_alloc (2));
   rtx insn = emit_insn (gen_rtx_PARALLEL (VOIDmode, gen_rtvec (2, set1, set2)));
   RTX_FRAME_RELATED_P (insn) = 1;
 
-  REG_NOTES (insn) = alloc_EXPR_LIST (REG_FRAME_RELATED_EXPR,
-				      copy_rtx (set1), REG_NOTES (insn));
-
-  REG_NOTES (insn) = alloc_EXPR_LIST (REG_FRAME_RELATED_EXPR,
-				      copy_rtx (set2), REG_NOTES (insn));
+  XVECEXP (dwarf, 0, 0) = copy_rtx (set1);
+  XVECEXP (dwarf, 0, 1) = copy_rtx (set2);
+  RTX_FRAME_RELATED_P (XVECEXP (dwarf, 0, 0)) = 1;
+  RTX_FRAME_RELATED_P (XVECEXP (dwarf, 0, 1)) = 1;
+  add_reg_note (insn, REG_FRAME_RELATED_EXPR, dwarf);
 }
 
 /* Similar like riscv_restore_reg, but restores two registers from memory
diff --git a/gcc/testsuite/gcc.target/riscv/xtheadmempair-4.c b/gcc/testsuite/gcc.target/riscv/xtheadmempair-4.c
new file mode 100644
index 00000000000..9aef4e15f8d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/xtheadmempair-4.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-skip-if "" { *-*-* } { "-O0" "-O1" "-g" "-Oz" "-Os" "-flto" } } */
+/* { dg-options "-march=rv64gc_xtheadmempair -mtune=thead-c906 -funwind-tables" { target { rv64 } } } */
+/* { dg-options "-march=rv32gc_xtheadmempair -mtune=thead-c906 -funwind-tables" { target { rv32 } } } */
+
+extern void bar (void);
+
+void foo (void)
+{
+  asm volatile (";my clobber list"
+		: : : "s0");
+  bar ();
+  asm volatile (";my clobber list"
+		: : : "s0");
+}
+
+/* { dg-final { scan-assembler-times "th.sdd\t" 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler ".cfi_offset 8, -16" { target { rv64 } } } } */
+/* { dg-final { scan-assembler ".cfi_offset 1, -8" { target { rv64 } } } } */
+
+/* { dg-final { scan-assembler-times "th.swd\t" 1 { target { rv32 } } } } */
+/* { dg-final { scan-assembler ".cfi_offset 8, -8" { target { rv32 } } } } */
+/* { dg-final { scan-assembler ".cfi_offset 1, -4" { target { rv32 } } } } */
+
+/* { dg-final { scan-assembler ".cfi_restore 1" } } */
+/* { dg-final { scan-assembler ".cfi_restore 8" } } */
+
+/* { dg-final { scan-assembler-times "th.ldd\t" 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times "th.lwd\t" 1 { target { rv32 } } } } */