On Mon, Apr 8, 2024 at 11:22 AM Kewen.Lin <li...@linux.ibm.com> wrote:
>
> Hi,
>
> As the comments in PR88309 show, there are two oversights
> in rs6000_gimple_fold_builtin that pass align in bytes to
> build_aligned_type but which actually requires align in
> bits, it causes unexpected ICE or hanging in function
> is_miss_rate_acceptable due to zero align_unit value.
>
> This patch is to fix them by converting bytes to bits, add
> an assertion on positive align_unit value and notes function
> build_aligned_type requires align measured in bits in its
> function comment.
>
> Bootstrapped and regtested on x86_64-redhat-linux,
> powerpc64-linux-gnu P8/P9 and powerpc64le-linux-gnu P9 and P10.
>
> Is it (the generic part code change) ok for trunk?
OK
> BR,
> Kewen
> -----
> PR target/88309
>
> Co-authored-by: Andrew Pinski <quic_apin...@quicinc.com>
>
> gcc/ChangeLog:
>
> * config/rs6000/rs6000-builtin.cc (rs6000_gimple_fold_builtin): Fix
> wrong align passed to function build_aligned_type.
> * tree-ssa-loop-prefetch.cc (is_miss_rate_acceptable): Add an
> assertion to ensure align_unit should be positive.
> * tree.cc (build_qualified_type): Update function comments.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/powerpc/pr88309.c: New test.
> ---
> gcc/config/rs6000/rs6000-builtin.cc | 4 ++--
> gcc/testsuite/gcc.target/powerpc/pr88309.c | 27 ++++++++++++++++++++++
> gcc/tree-ssa-loop-prefetch.cc | 2 ++
> gcc/tree.cc | 3 ++-
> 4 files changed, 33 insertions(+), 3 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/powerpc/pr88309.c
>
> diff --git a/gcc/config/rs6000/rs6000-builtin.cc
> b/gcc/config/rs6000/rs6000-builtin.cc
> index 6698274031b..e7d6204074c 100644
> --- a/gcc/config/rs6000/rs6000-builtin.cc
> +++ b/gcc/config/rs6000/rs6000-builtin.cc
> @@ -1900,7 +1900,7 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
> tree lhs_type = TREE_TYPE (lhs);
> /* In GIMPLE the type of the MEM_REF specifies the alignment. The
> required alignment (power) is 4 bytes regardless of data type. */
> - tree align_ltype = build_aligned_type (lhs_type, 4);
> + tree align_ltype = build_aligned_type (lhs_type, 32);
> /* POINTER_PLUS_EXPR wants the offset to be of type 'sizetype'.
> Create
> the tree using the value from arg0. The resulting type will match
> the type of arg1. */
> @@ -1944,7 +1944,7 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
> tree arg2_type = ptr_type_node;
> /* In GIMPLE the type of the MEM_REF specifies the alignment. The
> required alignment (power) is 4 bytes regardless of data type. */
> - tree align_stype = build_aligned_type (arg0_type, 4);
> + tree align_stype = build_aligned_type (arg0_type, 32);
> /* POINTER_PLUS_EXPR wants the offset to be of type 'sizetype'.
> Create
> the tree using the value from arg1. */
> gimple_seq stmts = NULL;
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr88309.c
> b/gcc/testsuite/gcc.target/powerpc/pr88309.c
> new file mode 100644
> index 00000000000..c0078cf2b8c
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr88309.c
> @@ -0,0 +1,27 @@
> +/* { dg-require-effective-target powerpc_vsx_ok } */
> +/* { dg-options "-mvsx -O2 -fprefetch-loop-arrays" } */
> +
> +/* Verify there is no ICE or hanging. */
> +
> +#include <altivec.h>
> +
> +void b(float *c, vector float a, vector float, vector float)
> +{
> + vector float d;
> + vector char ahbc;
> + vec_xst(vec_perm(a, d, ahbc), 0, c);
> +}
> +
> +vector float e(vector unsigned);
> +
> +void f() {
> + float *dst;
> + int g = 0;
> + for (;; g += 16) {
> + vector unsigned m, i;
> + vector unsigned n, j;
> + vector unsigned k, l;
> + b(dst + g * 3, e(m), e(n), e(k));
> + b(dst + (g + 4) * 3, e(i), e(j), e(l));
> + }
> +}
> diff --git a/gcc/tree-ssa-loop-prefetch.cc b/gcc/tree-ssa-loop-prefetch.cc
> index bbd98e03254..70073cc4fe4 100644
> --- a/gcc/tree-ssa-loop-prefetch.cc
> +++ b/gcc/tree-ssa-loop-prefetch.cc
> @@ -739,6 +739,8 @@ is_miss_rate_acceptable (unsigned HOST_WIDE_INT
> cache_line_size,
> if (delta >= (HOST_WIDE_INT) cache_line_size)
> return false;
>
> + gcc_assert (align_unit > 0);
> +
> miss_positions = 0;
> total_positions = (cache_line_size / align_unit) * distinct_iters;
> max_allowed_miss_positions = (ACCEPTABLE_MISS_RATE * total_positions) /
> 1000;
> diff --git a/gcc/tree.cc b/gcc/tree.cc
> index f801712c9dd..6f8400e6640 100644
> --- a/gcc/tree.cc
> +++ b/gcc/tree.cc
> @@ -5689,7 +5689,8 @@ build_qualified_type (tree type, int type_quals
> MEM_STAT_DECL)
> return t;
> }
>
> -/* Create a variant of type T with alignment ALIGN. */
> +/* Create a variant of type T with alignment ALIGN which
> + is measured in bits. */
>
> tree
> build_aligned_type (tree type, unsigned int align)
> --
> 2.43.0
