On Fri, 25 Mar 2022, Richard Biener wrote:
> We have
>
> return VIEW_CONVERT_EXPR<U>( VEC_PERM_EXPR < {<<< Unknown tree:
> compound_literal_expr
> V D.1984 = { 0 }; >>>, { 0 }} , {<<< Unknown tree:
> compound_literal_expr
> V D.1985 = { 0 }; >>>, { 0 }} , { 0, 0 } > & {(short int) SAVE_EXPR
> <c>, (short int) SAVE_EXPR <c>});
>
> where we gimplify the init CTORs to
>
> _1 = {{ 0 }, { 0 }};
> _2 = {{ 0 }, { 0 }};
>
> instead of to vector constants. That later runs into a bug in
> uniform_vector_p which doesn't handle CTORs of vector elements
> correctly.
>
> The following adjusts uniform_vector_p to handle CTORs of vector
> elements and also makes sure to simplify the CTORs to VECTOR_CSTs
> during gimplification by re-ordering the simplification to after
> CTOR flag recomputation.
>
> Bootstrapped and tested on x86_64-unknown-linux-gnu. At this
> point I'm leaning towards delaying the gimplification change
> to stage1 - do you agree?
I have now pushed the variant with just the tree.cc hunk.
Richard.
> Thanks,
> Richard.
>
> 2022-03-25 Richard Biener <rguent...@suse.de>
>
> PR middle-end/105049
> * gimplify.cc (gimplify_init_constructor): First gimplify,
> then simplify the result to a VECTOR_CST.
> * tree.cc (uniform_vector_p): Recurse for VECTOR_CST or
> CONSTRUCTOR first elements.
>
> * gcc/testsuite/gcc.dg/pr105049.c: New testcase.
> ---
> gcc/gimplify.cc | 33 ++++++++++++++++-----------------
> gcc/testsuite/gcc.dg/pr105049.c | 12 ++++++++++++
> gcc/tree.cc | 2 ++
> 3 files changed, 30 insertions(+), 17 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/pr105049.c
>
> diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
> index f62f150fc08..a866d4e6f56 100644
> --- a/gcc/gimplify.cc
> +++ b/gcc/gimplify.cc
> @@ -5390,6 +5390,22 @@ gimplify_init_constructor (tree *expr_p, gimple_seq
> *pre_p, gimple_seq *post_p,
> if (notify_temp_creation)
> return GS_OK;
>
> + /* Vector types use CONSTRUCTOR all the way through gimple
> + compilation as a general initializer. */
> + FOR_EACH_VEC_SAFE_ELT (elts, ix, ce)
> + {
> + enum gimplify_status tret;
> + tret = gimplify_expr (&ce->value, pre_p, post_p, is_gimple_val,
> + fb_rvalue);
> + if (tret == GS_ERROR)
> + ret = GS_ERROR;
> + else if (TREE_STATIC (ctor)
> + && !initializer_constant_valid_p (ce->value,
> + TREE_TYPE (ce->value)))
> + TREE_STATIC (ctor) = 0;
> + }
> + recompute_constructor_flags (ctor);
> +
> /* Go ahead and simplify constant constructors to VECTOR_CST. */
> if (TREE_CONSTANT (ctor))
> {
> @@ -5412,25 +5428,8 @@ gimplify_init_constructor (tree *expr_p, gimple_seq
> *pre_p, gimple_seq *post_p,
> TREE_OPERAND (*expr_p, 1) = build_vector_from_ctor (type, elts);
> break;
> }
> -
> - TREE_CONSTANT (ctor) = 0;
> }
>
> - /* Vector types use CONSTRUCTOR all the way through gimple
> - compilation as a general initializer. */
> - FOR_EACH_VEC_SAFE_ELT (elts, ix, ce)
> - {
> - enum gimplify_status tret;
> - tret = gimplify_expr (&ce->value, pre_p, post_p, is_gimple_val,
> - fb_rvalue);
> - if (tret == GS_ERROR)
> - ret = GS_ERROR;
> - else if (TREE_STATIC (ctor)
> - && !initializer_constant_valid_p (ce->value,
> - TREE_TYPE (ce->value)))
> - TREE_STATIC (ctor) = 0;
> - }
> - recompute_constructor_flags (ctor);
> if (!is_gimple_reg (TREE_OPERAND (*expr_p, 0)))
> TREE_OPERAND (*expr_p, 1) = get_formal_tmp_var (ctor, pre_p);
> }
> diff --git a/gcc/testsuite/gcc.dg/pr105049.c b/gcc/testsuite/gcc.dg/pr105049.c
> new file mode 100644
> index 00000000000..b0518c6a181
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/pr105049.c
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O -fno-tree-forwprop" } */
> +
> +typedef short __attribute__((__vector_size__ (sizeof(short)))) V;
> +typedef short __attribute__((__vector_size__ (2*sizeof(short)))) U;
> +char c;
> +
> +U
> +foo (void)
> +{
> + return __builtin_shufflevector ((V){}, (V){}, 0, 0) & c;
> +}
> diff --git a/gcc/tree.cc b/gcc/tree.cc
> index b8017af6cfc..ec200e9a7eb 100644
> --- a/gcc/tree.cc
> +++ b/gcc/tree.cc
> @@ -10266,6 +10266,8 @@ uniform_vector_p (const_tree vec)
> if (i != nelts)
> return NULL_TREE;
>
> + if (TREE_CODE (first) == CONSTRUCTOR || TREE_CODE (first) ==
> VECTOR_CST)
> + return uniform_vector_p (first);
> return first;
> }
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Ivo Totev; HRB 36809 (AG Nuernberg)
