Re: [PATCHv2] [aarch64] Fix target/95969: __builtin_aarch64_im_lane_boundsi interferes with gimple

[Richard Sandiford <richard.sandiford@arm.com>]

apinski--- via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> From: Andrew Pinski <apinski@marvell.com>
>
> This patch adds simple folding of __builtin_aarch64_im_lane_boundsi where
> we are not going to error out. It fixes the problem by the removal
> of the function from the IR.
>
> OK? Bootstrapped and tested on aarch64-linux-gnu with no regressions.
>
> gcc/ChangeLog:
>
> 	PR target/95969
> 	* config/aarch64/aarch64-builtins.c (aarch64_fold_builtin_lane_check):
> 	New function.
> 	(aarch64_general_fold_builtin): Handle AARCH64_SIMD_BUILTIN_LANE_CHECK.
> 	(aarch64_general_gimple_fold_builtin): Likewise.
>
> gcc/testsuite/ChangeLog:
>
> 	PR target/95969
> 	* gcc.target/aarch64/lane-bound-1.c: New test.
> 	* gcc.target/aarch64/lane-bound-2.c: New test.

OK, thanks.  Sorry for the slow reply, was away last week.

Richard

> ---
>  gcc/config/aarch64/aarch64-builtins.c         | 35 +++++++++++++++++++
>  .../gcc.target/aarch64/lane-bound-1.c         | 14 ++++++++
>  .../gcc.target/aarch64/lane-bound-2.c         | 10 ++++++
>  3 files changed, 59 insertions(+)
>  create mode 100644 gcc/testsuite/gcc.target/aarch64/lane-bound-1.c
>  create mode 100644 gcc/testsuite/gcc.target/aarch64/lane-bound-2.c
>
> diff --git a/gcc/config/aarch64/aarch64-builtins.c b/gcc/config/aarch64/aarch64-builtins.c
> index eef9fc0f444..119f67d4e4c 100644
> --- a/gcc/config/aarch64/aarch64-builtins.c
> +++ b/gcc/config/aarch64/aarch64-builtins.c
> @@ -29,6 +29,7 @@
>  #include "rtl.h"
>  #include "tree.h"
>  #include "gimple.h"
> +#include "ssa.h"
>  #include "memmodel.h"
>  #include "tm_p.h"
>  #include "expmed.h"
> @@ -2333,6 +2334,27 @@ aarch64_general_builtin_rsqrt (unsigned int fn)
>    return NULL_TREE;
>  }
>  
> +/* Return true if the lane check can be removed as there is no
> +   error going to be emitted.  */
> +static bool
> +aarch64_fold_builtin_lane_check (tree arg0, tree arg1, tree arg2)
> +{
> +  if (TREE_CODE (arg0) != INTEGER_CST)
> +    return false;
> +  if (TREE_CODE (arg1) != INTEGER_CST)
> +    return false;
> +  if (TREE_CODE (arg2) != INTEGER_CST)
> +    return false;
> +
> +  auto totalsize = wi::to_widest (arg0);
> +  auto elementsize = wi::to_widest (arg1);
> +  if (totalsize == 0 || elementsize == 0)
> +    return false;
> +  auto lane = wi::to_widest (arg2);
> +  auto high = wi::udiv_trunc (totalsize, elementsize);
> +  return wi::ltu_p (lane, high);
> +}
> +
>  #undef VAR1
>  #define VAR1(T, N, MAP, FLAG, A) \
>    case AARCH64_SIMD_BUILTIN_##T##_##N##A:
> @@ -2353,6 +2375,11 @@ aarch64_general_fold_builtin (unsigned int fcode, tree type,
>        VAR1 (UNOP, floatv4si, 2, ALL, v4sf)
>        VAR1 (UNOP, floatv2di, 2, ALL, v2df)
>  	return fold_build1 (FLOAT_EXPR, type, args[0]);
> +      case AARCH64_SIMD_BUILTIN_LANE_CHECK:
> +	gcc_assert (n_args == 3);
> +	if (aarch64_fold_builtin_lane_check (args[0], args[1], args[2]))
> +	  return void_node;
> +	break;
>        default:
>  	break;
>      }
> @@ -2440,6 +2467,14 @@ aarch64_general_gimple_fold_builtin (unsigned int fcode, gcall *stmt)
>  	    }
>  	  break;
>  	}
> +    case AARCH64_SIMD_BUILTIN_LANE_CHECK:
> +      if (aarch64_fold_builtin_lane_check (args[0], args[1], args[2]))
> +	{
> +	  unlink_stmt_vdef (stmt);
> +	  release_defs (stmt);
> +	  new_stmt = gimple_build_nop ();
> +	}
> +      break;
>      default:
>        break;
>      }
> diff --git a/gcc/testsuite/gcc.target/aarch64/lane-bound-1.c b/gcc/testsuite/gcc.target/aarch64/lane-bound-1.c
> new file mode 100644
> index 00000000000..bbbe679fd80
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/lane-bound-1.c
> @@ -0,0 +1,14 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +#include <arm_neon.h>
> +
> +void
> +f (float32x4_t **ptr)
> +{
> +  float32x4_t res = vsetq_lane_f32 (0.0f, **ptr, 0);
> +  **ptr = res;
> +}
> +/* GCC should be able to remove the call to "__builtin_aarch64_im_lane_boundsi"
> +   and optimize out the second load from *ptr.  */
> +/* { dg-final { scan-tree-dump-times "__builtin_aarch64_im_lane_boundsi" 0 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times " = \\\*ptr_" 1 "optimized" } } */
> diff --git a/gcc/testsuite/gcc.target/aarch64/lane-bound-2.c b/gcc/testsuite/gcc.target/aarch64/lane-bound-2.c
> new file mode 100644
> index 00000000000..923c94687c6
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/lane-bound-2.c
> @@ -0,0 +1,10 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-original" } */
> +void
> +f (void)
> +{
> +  __builtin_aarch64_im_lane_boundsi (16, 4, 0);
> +  __builtin_aarch64_im_lane_boundsi (8, 8, 0);
> +}
> +/* GCC should be able to optimize these out before gimplification. */
> +/* { dg-final { scan-tree-dump-times "__builtin_aarch64_im_lane_boundsi" 0 "original" } } */