[PATCH v2 10/14] LoongArch: Forbid ADDRESS_REG_REG in loongarch32

[Jiajie Chen via Gcc-patches]

LoongArch32 does not include LDX/STD instructions, and cannot lower
(plus (reg) (reg)) pattern. Forbid ADDRESS_REG_REG and do not emit
ldx/stx.

gcc/ChangeLog:

        * config/loongarch/loongarch.cc (loongarch_valid_index_p): Check
        ADDRESS_REG_REG pattern and fail in loongarch32.
        (loongarch_output_move_index): assertion failed if generating
        ldx/stx in loongarch32.

gcc/testsuite/ChangeLog:

        * gcc.target/loongarch/array-ldx.c: Add regression test for ldx
        in loongarch32.
---
 gcc/config/loongarch/loongarch.cc              | 4 +++-
 gcc/testsuite/gcc.target/loongarch/array-ldx.c | 6 ++++++
 2 files changed, 9 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/loongarch/array-ldx.c

diff --git a/gcc/config/loongarch/loongarch.cc 
b/gcc/config/loongarch/loongarch.cc
index 49df9509ba9..1fde680ccd4 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -2016,7 +2016,8 @@ loongarch_valid_index_p (struct loongarch_address_info 
*info, rtx x,
       && contains_reg_of_mode[GENERAL_REGS][GET_MODE (SUBREG_REG (index))])
     index = SUBREG_REG (index);
 
-  if (loongarch_valid_base_register_p (index, mode, strict_p))
+  /* LA32 does not provide LDX/STX.  */
+  if (loongarch_valid_base_register_p (index, mode, strict_p) && !TARGET_32BIT)
     {
       info->type = ADDRESS_REG_REG;
       info->offset = index;
@@ -3853,6 +3854,7 @@ loongarch_output_move_index (rtx x, machine_mode mode, 
bool ldr)
       }
     };
 
+  gcc_assert (!TARGET_32BIT);
   return insn[ldr][index];
 }
 
diff --git a/gcc/testsuite/gcc.target/loongarch/array-ldx.c 
b/gcc/testsuite/gcc.target/loongarch/array-ldx.c
new file mode 100644
index 00000000000..0797af3bbfb
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/array-ldx.c
@@ -0,0 +1,6 @@
+/* { dg-do compile } */
+/* { dg-options "-march=loongarch32 -mabi=ilp32d -O2" } */
+long long foo(long long *arr, long long index)
+{
+       return arr[index];
+}
\ No newline at end of file
-- 
2.41.0