From: Richard Sandiford <richard.sandiford@arm.com>
To: "Andre Vieira \(lists\)" <andre.simoesdiasvieira@arm.com>
Cc: Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>,
"gcc-patches\@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Subject: Re: [AArch64] Fix NEON load/store gimple lowering and big-endian testisms
Date: Thu, 04 Nov 2021 17:48:35 +0000 [thread overview]
Message-ID: <mpta6ij7qx8.fsf@arm.com> (raw)
In-Reply-To: <0911f6c6-7832-026c-36c1-cbb576944a62@arm.com> (Andre Vieira's message of "Thu, 4 Nov 2021 09:55:37 +0000")
"Andre Vieira (lists)" <andre.simoesdiasvieira@arm.com> writes:
> Hi,
>
> This should address the ubsan bootstrap build and big-endian testisms
> reported against the last NEON load/store gimple lowering patch. I also
> fixed a follow-up issue where the alias information was leading to a bad
> codegen transformation. The NEON intrinsics specifications do not forbid
> the use of memory accesses with different pointer types. In fact you
> will see intrinsic user code loading a int16x8_t vector from an int
> pointer, so we must make sure GCC is aware a NEON memory access of an
> 'int' pointer can alias with a 'short' pointer.
>
> Bootstrapped aarch64-linux-gnu (also did an ubsan bootstrap).
>
> Is this OK for trunk?
>
> gcc/ChangeLog:
>
> * config/aarch64/aarch64-builtins.c
> (aarch64_general_gimple_fold_builtin): Change pointer alignment and alias.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/aarch64/fmla_intrinsic_1.c: Fix big-endian testism.
> * gcc.target/aarch64/fmls_intrinsic_1.c: Likewise.
> * gcc.target/aarch64/fmul_intrinsic_1.c: Likewise.
>
> diff --git a/gcc/config/aarch64/aarch64-builtins.c b/gcc/config/aarch64/aarch64-builtins.c
> index a815e4cfbccab692ca688ba87c71b06c304abbfb..fc8fcb02c55e22963d2a3bf77b4749eb5b1c1561 100644
> --- a/gcc/config/aarch64/aarch64-builtins.c
> +++ b/gcc/config/aarch64/aarch64-builtins.c
> @@ -2486,16 +2486,22 @@ aarch64_general_gimple_fold_builtin (unsigned int fcode, gcall *stmt,
> aarch64_simd_type_info simd_type
> = aarch64_simd_types[mem_type];
> tree elt_ptr_type = build_pointer_type (simd_type.eltype);
> + elt_ptr_type = build_distinct_type_copy (elt_ptr_type);
> + TYPE_REF_CAN_ALIAS_ALL (elt_ptr_type) = true;
> tree zero = build_zero_cst (elt_ptr_type);
> gimple_seq stmts = NULL;
> tree base = gimple_convert (&stmts, elt_ptr_type,
> args[0]);
This conversion seems redundant. Do things work if we use args[0]
directly?
> + /* Use element type alignment. */
> + tree access_type
> + = build_aligned_type (simd_type.itype,
> + TYPE_ALIGN (TREE_TYPE (simd_type.itype)));
I think simd_type.eltype is more natural than TREE_TYPE (simd_type.itype)
here, to match the pointer target type.
Same idea for the stores.
> if (stmts)
> gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
> new_stmt
> = gimple_build_assign (gimple_get_lhs (stmt),
> fold_build2 (MEM_REF,
> - simd_type.itype,
> + access_type,
> base, zero));
> }
> break;
> @@ -2508,17 +2514,22 @@ aarch64_general_gimple_fold_builtin (unsigned int fcode, gcall *stmt,
> aarch64_simd_type_info simd_type
> = aarch64_simd_types[mem_type];
> tree elt_ptr_type = build_pointer_type (simd_type.eltype);
> + elt_ptr_type = build_distinct_type_copy (elt_ptr_type);
> + TYPE_REF_CAN_ALIAS_ALL (elt_ptr_type) = true;
> tree zero = build_zero_cst (elt_ptr_type);
> gimple_seq stmts = NULL;
> tree base = gimple_convert (&stmts, elt_ptr_type,
> args[0]);
> + /* Use element type alignment. */
> + tree access_type
> + = build_aligned_type (simd_type.itype,
> + TYPE_ALIGN (TREE_TYPE (simd_type.itype)));
> if (stmts)
> gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
> new_stmt
> - = gimple_build_assign (fold_build2 (MEM_REF,
> - simd_type.itype,
> - base,
> - zero), args[1]);
> + = gimple_build_assign (fold_build2 (MEM_REF, access_type,
> + base, zero),
> + args[1]);
> }
> break;
>
> diff --git a/gcc/testsuite/gcc.target/aarch64/fmla_intrinsic_1.c b/gcc/testsuite/gcc.target/aarch64/fmla_intrinsic_1.c
> index adb787a8599af23847dd62dcd153d7cfe43dacc0..c1aeb06e74753052c2ee441b361b92148f1b4b0a 100644
> --- a/gcc/testsuite/gcc.target/aarch64/fmla_intrinsic_1.c
> +++ b/gcc/testsuite/gcc.target/aarch64/fmla_intrinsic_1.c
> @@ -107,10 +107,12 @@ main (int argc, char **argv)
>
> /* vfma_lane_f64.
> vfma_laneq_f64. */
> -/* { dg-final { scan-assembler-times "fmadd\\td\[0-9\]+\, d\[0-9\]+\, d\[0-9\]+\, d\[0-9\]+" 2 } } */
> +/* { dg-final { scan-assembler-times "fmadd\\td\[0-9\]+\, d\[0-9\]+\, d\[0-9\]+\, d\[0-9\]+" 1 { target aarch64_big_endian } } } */
> +/* { dg-final { scan-assembler-times "fmadd\\td\[0-9\]+\, d\[0-9\]+\, d\[0-9\]+\, d\[0-9\]+" 2 { target aarch64_little_endian } } } */
Could you explain this in more detail? What happens for little-endian
vs. big-endian?
Thanks,
Richard
>
> /* vfmaq_lane_f64.
> vfmaq_laneq_f64. */
> -/* { dg-final { scan-assembler-times "fmla\\tv\[0-9\]+\.2d, v\[0-9\]+\.2d, v\[0-9\]+\.d\\\[\[0-9\]+\\\]" 2 } } */
> +/* { dg-final { scan-assembler-times "fmla\\tv\[0-9\]+\.2d, v\[0-9\]+\.2d, v\[0-9\]+\.d\\\[\[0-9\]+\\\]" 3 { target aarch64_big_endian } } } */
> +/* { dg-final { scan-assembler-times "fmla\\tv\[0-9\]+\.2d, v\[0-9\]+\.2d, v\[0-9\]+\.d\\\[\[0-9\]+\\\]" 2 { target aarch64_little_endian } } } */
>
>
> diff --git a/gcc/testsuite/gcc.target/aarch64/fmls_intrinsic_1.c b/gcc/testsuite/gcc.target/aarch64/fmls_intrinsic_1.c
> index 865def28c3f4d04042ab495d232bb865cabb2b50..3137ea91e809e37de589091e9bbd43bfe4d221a1 100644
> --- a/gcc/testsuite/gcc.target/aarch64/fmls_intrinsic_1.c
> +++ b/gcc/testsuite/gcc.target/aarch64/fmls_intrinsic_1.c
> @@ -108,10 +108,12 @@ main (int argc, char **argv)
>
> /* vfms_lane_f64.
> vfms_laneq_f64. */
> -/* { dg-final { scan-assembler-times "fmsub\\td\[0-9\]+\, d\[0-9\]+\, d\[0-9\]+\, d\[0-9\]+" 2 } } */
> +/* { dg-final { scan-assembler-times "fmsub\\td\[0-9\]+\, d\[0-9\]+\, d\[0-9\]+\, d\[0-9\]+" 1 { target aarch64_big_endian } } } */
> +/* { dg-final { scan-assembler-times "fmsub\\td\[0-9\]+\, d\[0-9\]+\, d\[0-9\]+\, d\[0-9\]+" 2 { target aarch64_little_endian } } } */
>
> /* vfmsq_lane_f64.
> vfmsq_laneq_f64. */
> -/* { dg-final { scan-assembler-times "fmls\\tv\[0-9\]+\.2d, v\[0-9\]+\.2d, v\[0-9\]+\.d\\\[\[0-9\]+\\\]" 2 } } */
> +/* { dg-final { scan-assembler-times "fmls\\tv\[0-9\]+\.2d, v\[0-9\]+\.2d, v\[0-9\]+\.d\\\[\[0-9\]+\\\]" 3 { target aarch64_big_endian } } } */
> +/* { dg-final { scan-assembler-times "fmls\\tv\[0-9\]+\.2d, v\[0-9\]+\.2d, v\[0-9\]+\.d\\\[\[0-9\]+\\\]" 2 { target aarch64_little_endian } } } */
>
>
> diff --git a/gcc/testsuite/gcc.target/aarch64/fmul_intrinsic_1.c b/gcc/testsuite/gcc.target/aarch64/fmul_intrinsic_1.c
> index d01095e81c1e45dc1da998aa337ba551b3752ebe..7d4829c40d7042226f2f09fab9fdfa7c3dd211c4 100644
> --- a/gcc/testsuite/gcc.target/aarch64/fmul_intrinsic_1.c
> +++ b/gcc/testsuite/gcc.target/aarch64/fmul_intrinsic_1.c
> @@ -107,10 +107,12 @@ main (int argc, char **argv)
>
> /* vmul_lane_f64.
> Vmul_laneq_f64. */
> -/* { dg-final { scan-assembler-times "fmul\\td\[0-9\]+, d\[0-9\]+, d\[0-9\]+" 2 } } */
> +/* { dg-final { scan-assembler-times "fmul\\td\[0-9\]+, d\[0-9\]+, d\[0-9\]+" 1 { target aarch64_big_endian } } } */
> +/* { dg-final { scan-assembler-times "fmul\\td\[0-9\]+, d\[0-9\]+, d\[0-9\]+" 2 { target aarch64_little_endian } } } */
>
> /* vmulq_lane_f64.
> vmulq_laneq_f64. */
> -/* { dg-final { scan-assembler-times "fmul\\tv\[0-9\]+\.2d, v\[0-9\]+\.2d, v\[0-9\]+\.d\\\[\[0-9\]+\\\]" 2 } } */
> +/* { dg-final { scan-assembler-times "fmul\\tv\[0-9\]+\.2d, v\[0-9\]+\.2d, v\[0-9\]+\.d\\\[\[0-9\]+\\\]" 3 { target aarch64_big_endian } } } */
> +/* { dg-final { scan-assembler-times "fmul\\tv\[0-9\]+\.2d, v\[0-9\]+\.2d, v\[0-9\]+\.d\\\[\[0-9\]+\\\]" 2 { target aarch64_little_endian } } } */
>
>
next prev parent reply other threads:[~2021-11-04 17:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-04 9:55 Andre Vieira (lists)
2021-11-04 17:48 ` Richard Sandiford [this message]
2021-11-05 10:27 ` Richard Biener
2021-11-09 9:19 ` Andre Vieira (lists)
2021-11-09 10:47 ` Richard Biener
2021-11-09 12:24 ` [AArch64] Fix big-endian testisms introduced by NEON gimple lowering patch Andre Vieira (lists)
2021-11-09 12:27 ` [AArch64] Fix TBAA information when lowering NEON loads and stores to gimple Andre Vieira (lists)
2021-11-09 15:00 ` Richard Sandiford
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