Re: [PATCH] GIMPLE_FOLD: Fix gimple fold for LEN_MASK_{LOAD,STORE}

[Richard Biener <rguenther@suse.de>]

On Mon, 26 Jun 2023, juzhe.zhong@rivai.ai wrote:

> From: Ju-Zhe Zhong <juzhe.zhong@rivai.ai>
> 
> Hi, previous I made a mistake on GIMPLE_FOLD of LEN_MASK_{LOAD,STORE}.
> 
> We should fold LEN_MASK_{LOAD,STORE} (bias+len) == vf (nunits instead of bytesize) && mask = all trues mask
> 
> into:
>    MEM_REF [...].
> 
> This patch added testcase to test gimple fold of LEN_MASK_{LOAD,STORE}.
> 
> Ok for trunk ?

Err, but then the IFN_LEN_LOAD case is wrong as well - we surely do
not want differing behavior here.

So please fix them both?

> gcc/ChangeLog:
> 
>         * gimple-fold.cc (gimple_fold_partial_load_store_mem_ref): Fix LEN_MASK_{LOAD,STORE}.
> 
> gcc/testsuite/ChangeLog:
> 
>         * gcc.target/riscv/rvv/autovec/partial/gimple_fold-1.c: New test.
> 
> ---
>  gcc/gimple-fold.cc                            | 16 ++++---
>  .../riscv/rvv/autovec/partial/gimple_fold-1.c | 43 +++++++++++++++++++
>  2 files changed, 54 insertions(+), 5 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/partial/gimple_fold-1.c
> 
> diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc
> index 3d46b76edeb..94e79c32218 100644
> --- a/gcc/gimple-fold.cc
> +++ b/gcc/gimple-fold.cc
> @@ -5397,19 +5397,25 @@ gimple_fold_partial_load_store_mem_ref (gcall *call, tree vectype, bool mask_p)
>        unsigned int nargs = gimple_call_num_args (call);
>        tree bias = gimple_call_arg (call, nargs - 1);
>        gcc_assert (TREE_CODE (bias) == INTEGER_CST);
> -      if (maybe_ne (wi::to_poly_widest (basic_len) - wi::to_widest (bias),
> -		    GET_MODE_SIZE (TYPE_MODE (vectype))))
> -	return NULL_TREE;
>  
> -      /* For LEN_MASK_{LOAD,STORE}, we should also check whether
> -	  the mask is all ones mask.  */
>        internal_fn ifn = gimple_call_internal_fn (call);
>        if (ifn == IFN_LEN_MASK_LOAD || ifn == IFN_LEN_MASK_STORE)
>  	{
> +	  /* We fold LEN_MASK_{LOAD,STORE} into MEM_REF when (len + bias) == VF
> +	     and mask = all trues mask.  */
> +	  if (maybe_ne (wi::to_poly_widest (basic_len) + wi::to_widest (bias),
> +			GET_MODE_NUNITS (TYPE_MODE (vectype))))
> +	    return NULL_TREE;
>  	  tree mask = gimple_call_arg (call, internal_fn_mask_index (ifn));
>  	  if (!integer_all_onesp (mask))
>  	    return NULL_TREE;
>  	}
> +      else
> +	{
> +	  if (maybe_ne (wi::to_poly_widest (basic_len) - wi::to_widest (bias),
> +			GET_MODE_SIZE (TYPE_MODE (vectype))))
> +	    return NULL_TREE;
> +	}
>      }
>  
>    unsigned HOST_WIDE_INT align = tree_to_uhwi (alias_align);
> diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/partial/gimple_fold-1.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/partial/gimple_fold-1.c
> new file mode 100644
> index 00000000000..23407a2d3f4
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/partial/gimple_fold-1.c
> @@ -0,0 +1,43 @@
> +/* { dg-do compile } */
> +/* { dg-options "-march=rv32gcv -mabi=ilp32d --param riscv-autovec-preference=fixed-vlmax --param riscv-autovec-lmul=m8 -O3 -fdump-tree-optimized-details" } */
> +
> +#include <stdint-gcc.h>
> +
> +#define SZ 255
> +
> +#define DEF(TYPE) void fn_##TYPE (TYPE *__restrict a);
> +
> +#define RUN(TYPE)                                                              \
> +  TYPE a##TYPE[SZ];                                                            \
> +  for (int i = 0; i < SZ; i++)                                                 \
> +    {                                                                          \
> +      a##TYPE[i] = 127;                                                        \
> +    }                                                                          \
> +  fn_##TYPE (a##TYPE);
> +
> +#define RUN_ALL()                                                              \
> +  RUN (int8_t)                                                                 \
> +  RUN (int16_t)                                                                \
> +  RUN (int32_t)                                                                \
> +  RUN (int64_t)                                                                \
> +  RUN (uint8_t)                                                                \
> +  RUN (uint16_t)                                                               \
> +  RUN (uint32_t)                                                               \
> +  RUN (uint64_t)
> +
> +DEF (int8_t)
> +DEF (int16_t)
> +DEF (int32_t)
> +DEF (int64_t)
> +DEF (uint8_t)
> +DEF (uint16_t)
> +DEF (uint32_t)
> +DEF (uint64_t)
> +
> +int
> +main ()
> +{
> +  RUN_ALL ()
> +}
> +
> +/* { dg-final { scan-tree-dump-times "\.LEN_MASK_STORE" 6 "optimized" } } */
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)