Looks like the first patch was missing a change I had made to prevent 
mve_bool_vec_to_const ICEing if called with a non-vector immediate. Now 
included.

On 24/01/2023 13:56, Andre Vieira (lists) via Gcc-patches wrote:
> Hi,
> 
> This patch fixes the way we synthesize MVE predicate immediates and 
> fixes some other inconsistencies around predicates. For instance this 
> patch fixes the modes used in the vctp intrinsics, to couple them with 
> predicate modes with the appropriate lane numbers. For this V2QI is 
> added to represent a predicate created by vctp64q. The reason we use 
> V2QI and not for instance a V2BI with 8-bit boolean modes is because we 
> are trying to avoid having two 'INT' modes of the same size. We make 
> sure we use the V2QI mode instead of HI for any instruction working on 
> two lanes of 64-bits consuming a predicate.
> 
> Bootstrapped on aarch64-none-linux-gnu and regression tested on 
> arm-none-eabi and armeb-none-eabi for armv8.1-m.main+mve.fp.
> 
> OK for trunk?
> 
> gcc/ChangeLog:
> 
>          PR target/108443
>          * config/arm/arm.h (VALID_MVE_PRED_MODE): Add V2QI.
> * config/arm/arm.cc (thumb2_legitimate_address_p): Use HImode for
>      addressing MVE predicate modes.
>      (mve_bool_vec_to_const): Change to represent correct MVE predicate
>      format.
>      (arm_hard_regno_mode_ok): Use VALID_MVE_PRED_MODE instead of 
> checking modes.
>      (arm_vector_mode_supported_p): Likewise.
>      (arm_mode_to_pred_mode): Add V2QI.
>      * config/arm/arm-builtins.cc (UNOP_PRED_UNONE_QUALIFIERS): New 
> qualifier.
>      (UNOP_PRED_PRED_QUALIFIERS): New qualifier
>      (BINOP_PRED_UNONE_PRED_QUALIFIERS): New qualifier.
>      (v2qi_UP): New macro.
>      (v4bi_UP): New macro.
>      (v8bi_UP): New macro.
>      (v16bi_UP): New macro.
>      (arm_expand_builtin_args): Make it able to expand the new predicate
>      modes.
>      * config/arm/arm-modes.def (V2QI): New mode.
>      * config/arm/arm-simd-builtin-types.def (Pred1x16_t, Pred2x8_t
>      Pred4x4_t): Remove unused predicate builtin types.
>      * config/arm/arm_mve.h (__arm_vctp16q, __arm_vctp32q, __arm_vctp64q,
>      __arm_vctp8q, __arm_vpnot, __arm_vctp8q_m, __arm_vctp64q_m,
>      __arm_vctp32q_m, __arm_vctp16q_m): Use predicate modes.
>      * config/arm/arm_mve_builtins.def (vctp16q, vctp32q, vctp64q, vctp8q,
>      vpnot, vctp8q_m, vctp16q_m, vctp32q_m, vctp64q_m): Likewise.
>      * config/arm/constraints.md (DB): Check for VALID_MVE_PRED_MODE 
> instead
>      of MODE_VECTOR_BOOL.
>      * config/arm/iterators.md (MVE_7, MVE_7_HI): Add V2QI
>      (MVE_VPRED): Likewise.
>          (MVE_vpred): Add V2QI and map upper case predicate modes to 
> lower case.
>      (MVE_vctp): New mode attribute.
>      (mode1): Remove.
>      (VCTPQ): Remove.
>      (VCTPQ_M): Remove.
>      * config/arm/mve.md (mve_vctp<mode1>qhi): Rename this...
>      (mve_vctp<MVE_vctp>q<MVE_vpred>): ... to this. And use new mode
>      attributes.
>      (mve_vpnothi): Rename this...
>      (mve_vpnotv16bi): ... to this.
>      (mve_vctp<mode1>q_mhi): Rename this...
>      (mve_vctp<MVE_vctp>q_m<MVE_vpred>):... to this.
>      (mve_vldrdq_gather_base_z_<supf>v2di,
>      mve_vldrdq_gather_offset_z_<supf>v2di,
>      mve_vldrdq_gather_shifted_offset_z_<supf>v2di,
>      mve_vstrdq_scatter_base_p_<supf>v2di,
>      mve_vstrdq_scatter_offset_p_<supf>v2di,
>      mve_vstrdq_scatter_offset_p_<supf>v2di_insn,
>      mve_vstrdq_scatter_shifted_offset_p_<supf>v2di,
>      mve_vstrdq_scatter_shifted_offset_p_<supf>v2di_insn,
>      mve_vstrdq_scatter_base_wb_p_<supf>v2di,
>      mve_vldrdq_gather_base_wb_z_<supf>v2di,
>      mve_vldrdq_gather_base_nowb_z_<supf>v2di,
>      mve_vldrdq_gather_base_wb_z_<supf>v2di_insn):  Use V2QI insead of 
> HI for predicates.
>      * config/arm/unspecs.md (VCTP8Q, VCTP16Q, VCTP32Q, VCTP64Q): Replace
>      these...
>      (VCTP): ... with this.
>      (VCTP8Q_M, VCTP16Q_M, VCTP32Q_M, VCTP64Q_M): Replace these...
>      (VCTP_M): ... with this.
>      * config/arm/vfp.md (*thumb2_movhi_vfp, *thumb2_movhi_fp16): Use 
> VALID_MVE_PRED_MODE
>          instead of checking for MODE_VECTOR_BOOL class.
> 
> 
> gcc/testsuite/ChangeLog:
> 
>          * gcc.dg/rtl/arm/mve-vxbi.c: Use new predicate modes.
>          * gcc.target/arm/mve/pr108443-run.c: New test.
>          * gcc.target/arm/mve/pr108443.c: New test.