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Re: [PATCH] RISC-V: Add Sign/Zero extend patterns for PIC loads
- From: Palmer Dabbelt <palmer at dabbelt dot com>
- To: gcc-patches at gcc dot gnu dot org
- Cc: patches at groups dot riscv dot org
- Date: Wed, 25 Oct 2017 15:46:35 -0700 (PDT)
- Subject: Re: [PATCH] RISC-V: Add Sign/Zero extend patterns for PIC loads
- Authentication-results: sourceware.org; auth=none
Committed.
On Tue, 24 Oct 2017 10:55:46 PDT (-0700), Palmer Dabbelt wrote:
> Loads on RISC-V are sign-extending by default, but we weren't telling
> GCC this in our PIC load patterns. This corrects the problem, and adds
> a zero-extending pattern as well.
>
> gcc/ChangeLog
>
> 2017-10-24 Palmer Dabbelt <palmer@dabbelt.com>
>
> * config/riscv/riscv.md (ZERO_EXTEND_LOAD): Define.
> * config/riscv/pic.md (local_pic_load): Rename to local_pic_load_s,
> mark as a sign-extending load.
> (local_pic_load_u): Define.
> ---
> gcc/config/riscv/pic.md | 11 +++++++++--
> gcc/config/riscv/riscv.md | 3 +++
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/config/riscv/pic.md b/gcc/config/riscv/pic.md
> index 6a29ead32d36..03b8f9bc669e 100644
> --- a/gcc/config/riscv/pic.md
> +++ b/gcc/config/riscv/pic.md
> @@ -22,13 +22,20 @@
> ;; Simplify PIC loads to static variables.
> ;; These should go away once we figure out how to emit auipc discretely.
>
> -(define_insn "*local_pic_load<mode>"
> +(define_insn "*local_pic_load_s<mode>"
> [(set (match_operand:ANYI 0 "register_operand" "=r")
> - (mem:ANYI (match_operand 1 "absolute_symbolic_operand" "")))]
> + (sign_extend:ANYI (mem:ANYI (match_operand 1 "absolute_symbolic_operand" ""))))]
> "USE_LOAD_ADDRESS_MACRO (operands[1])"
> "<load>\t%0,%1"
> [(set (attr "length") (const_int 8))])
>
> +(define_insn "*local_pic_load_u<mode>"
> + [(set (match_operand:ZERO_EXTEND_LOAD 0 "register_operand" "=r")
> + (zero_extend:ZERO_EXTEND_LOAD (mem:ZERO_EXTEND_LOAD (match_operand 1 "absolute_symbolic_operand" ""))))]
> + "USE_LOAD_ADDRESS_MACRO (operands[1])"
> + "<load>u\t%0,%1"
> + [(set (attr "length") (const_int 8))])
> +
> (define_insn "*local_pic_load<mode>"
> [(set (match_operand:ANYF 0 "register_operand" "=f")
> (mem:ANYF (match_operand 1 "absolute_symbolic_operand" "")))
> diff --git a/gcc/config/riscv/riscv.md b/gcc/config/riscv/riscv.md
> index fd9236c7c170..9f056bbcda4f 100644
> --- a/gcc/config/riscv/riscv.md
> +++ b/gcc/config/riscv/riscv.md
> @@ -259,6 +259,9 @@
> ;; Iterator for QImode extension patterns.
> (define_mode_iterator SUPERQI [HI SI (DI "TARGET_64BIT")])
>
> +;; Iterator for extending loads.
> +(define_mode_iterator ZERO_EXTEND_LOAD [QI HI (SI "TARGET_64BIT")])
> +
> ;; Iterator for hardware integer modes narrower than XLEN.
> (define_mode_iterator SUBX [QI HI (SI "TARGET_64BIT")])