target-arm: Fix TCG temp leaks for WI and UNDEF VFP sysreg writes

Fix a leak of a TCG temporary in code paths for VFP system register
writes for cases which UNDEF or are write-ignored.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

target-arm/translate.c

@@ -2737,7 +2737,6 @@ static int disas_vfp_insn(CPUARMState * env, DisasContext *s, uint32_t insn)
                     }
                 } else {
                     /* arm->vfp */
-                    tmp = load_reg(s, rd);
                     if (insn & (1 << 21)) {
                         rn >>= 1;
                         /* system register */
@@ -2748,6 +2747,7 @@ static int disas_vfp_insn(CPUARMState * env, DisasContext *s, uint32_t insn)
                             /* Writes are ignored.  */
                             break;
                         case ARM_VFP_FPSCR:
+                            tmp = load_reg(s, rd);
                             gen_helper_vfp_set_fpscr(cpu_env, tmp);
                             tcg_temp_free_i32(tmp);
                             gen_lookup_tb(s);
@@ -2757,18 +2757,21 @@ static int disas_vfp_insn(CPUARMState * env, DisasContext *s, uint32_t insn)
                                 return 1;
                             /* TODO: VFP subarchitecture support.
                              * For now, keep the EN bit only */
+                            tmp = load_reg(s, rd);
                             tcg_gen_andi_i32(tmp, tmp, 1 << 30);
                             store_cpu_field(tmp, vfp.xregs[rn]);
                             gen_lookup_tb(s);
                             break;
                         case ARM_VFP_FPINST:
                         case ARM_VFP_FPINST2:
+                            tmp = load_reg(s, rd);
                             store_cpu_field(tmp, vfp.xregs[rn]);
                             break;
                         default:
                             return 1;
                         }
                     } else {
+                        tmp = load_reg(s, rd);
                         gen_vfp_msr(tmp);
                         gen_mov_vreg_F0(0, rn);
                     }