[PATCH] LoongArch: Fix invalid subregs in xorsign [PR118501]

[Xi Ruoyao]

The test case added in r15-7073 now triggers an ICE, indicating we need
the same fix as AArch64.

gcc/ChangeLog:

        PR target/118501
        * config/loongarch/loongarch.md (@xorsign<mode>3): Use
        force_lowpart_subreg.
---

Bootstrapped and regtested on loongarch64-linux-gnu, ok for trunk?

 gcc/config/loongarch/loongarch.md | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/gcc/config/loongarch/loongarch.md 
b/gcc/config/loongarch/loongarch.md
index 0325994ebd6..04a9a79d548 100644
--- a/gcc/config/loongarch/loongarch.md
+++ b/gcc/config/loongarch/loongarch.md
@@ -1343,8 +1343,8 @@ (define_expand "@xorsign<mode>3"
   machine_mode lsx_mode
     = <MODE>mode == SFmode ? V4SFmode : V2DFmode;
   rtx tmp = gen_reg_rtx (lsx_mode);
-  rtx op1 = lowpart_subreg (lsx_mode, operands[1], <MODE>mode);
-  rtx op2 = lowpart_subreg (lsx_mode, operands[2], <MODE>mode);
+  rtx op1 = force_lowpart_subreg (lsx_mode, operands[1], <MODE>mode);
+  rtx op2 = force_lowpart_subreg (lsx_mode, operands[2], <MODE>mode);
   emit_insn (gen_xorsign3 (lsx_mode, tmp, op1, op2));
   emit_move_insn (operands[0],
           lowpart_subreg (<MODE>mode, tmp, lsx_mode));
-- 
2.48.1