target/arm: Fix decode of fp16 vector fabs, fneg, fsqrt

These opcodes are only supported as vector operations,
not as advsimd scalar.  Set only_in_vector, and remove
the unreachable implementation of scalar fneg.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20241211163036.2297116-24-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/target/arm/tcg/translate-a64.c b/target/arm/tcg/translate-a64.c
index a99f3d0d135f065df9b81f6a8780c7d119561b41..3c1784593a4938283881084f8d7d3a29ec238536 100644 (file)
--- a/target/arm/tcg/translate-a64.c
+++ b/target/arm/tcg/translate-a64.c
@@ -10816,10 +10816,13 @@ static void disas_simd_two_reg_misc_fp16(DisasContext *s, uint32_t insn)
         break;
     case 0x2f: /* FABS */
     case 0x6f: /* FNEG */
+        only_in_vector = true;
         need_fpst = false;
         break;
     case 0x7d: /* FRSQRTE */
+        break;
     case 0x7f: /* FSQRT (vector) */
+        only_in_vector = true;
         break;
     default:
         unallocated_encoding(s);
@@ -10877,9 +10880,6 @@ static void disas_simd_two_reg_misc_fp16(DisasContext *s, uint32_t insn)
         case 0x7b: /* FCVTZU */
             gen_helper_advsimd_f16touinth(tcg_res, tcg_op, tcg_fpstatus);
             break;
-        case 0x6f: /* FNEG */
-            tcg_gen_xori_i32(tcg_res, tcg_op, 0x8000);
-            break;
         case 0x7d: /* FRSQRTE */
             gen_helper_rsqrte_f16(tcg_res, tcg_op, tcg_fpstatus);
             break;