On June 8, 2020 10:14:40 AM GMT+02:00, Jakub Jelinek <ja...@redhat.com> wrote:
>Hi!
>
>As mentioned in the PR, the problem is that at least the x86 backend
>asumes
>that the vec_unpack* and vec_pack* optabs with integral modes are for
>the
>AVX512-ish vector masks rather than for very small vectors done in
>GPRs.
>The only other target that seems to have a scalar mode vec_{,un}pack*
>optab
>is aarch64 as discussed in the PR, so there is also a condition for
>that.
>All other targets have just vector mode optabs.
>
>Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
Richard.
>2020-06-08 Jakub Jelinek <ja...@redhat.com>
>
> PR target/95528
> * tree-ssa-forwprop.c (simplify_vector_constructor): Don't use
> VEC_UNPACK*_EXPR or VEC_PACK_TRUNC_EXPR with scalar modes unless the
> type is vector boolean.
>
> * g++.dg/opt/pr95528.C: New test.
>
>--- gcc/tree-ssa-forwprop.c.jj 2020-05-26 09:28:53.244149208 +0200
>+++ gcc/tree-ssa-forwprop.c 2020-06-05 13:10:26.992648945 +0200
>@@ -2401,6 +2401,10 @@ simplify_vector_constructor (gimple_stmt
> && (dblvectype
> = build_vector_type (TREE_TYPE (TREE_TYPE (orig[0])),
> nelts * 2))
>+ /* Only use it for vector modes or for vector booleans
>represented
>+ as scalar bitmasks. See PR95528. */
>+ && (VECTOR_MODE_P (TYPE_MODE (dblvectype))
>+ || VECTOR_BOOLEAN_TYPE_P (dblvectype))
> && (optab = optab_for_tree_code (FLOAT_TYPE_P (TREE_TYPE (type))
> ? VEC_UNPACK_FLOAT_LO_EXPR
> : VEC_UNPACK_LO_EXPR,
>@@ -2442,6 +2446,13 @@ simplify_vector_constructor (gimple_stmt
> && (halfvectype
> = build_vector_type (TREE_TYPE (TREE_TYPE (orig[0])),
> nelts / 2))
>+ /* Only use it for vector modes or for vector booleans
>+ represented as scalar bitmasks, or allow halfvectype
>+ be the element mode. See PR95528. */
>+ && (VECTOR_MODE_P (TYPE_MODE (halfvectype))
>+ || VECTOR_BOOLEAN_TYPE_P (halfvectype)
>+ || (TYPE_MODE (halfvectype)
>+ == TYPE_MODE (TREE_TYPE (halfvectype))))
> && (optab = optab_for_tree_code (VEC_PACK_TRUNC_EXPR,
> halfvectype,
> optab_default))
>--- gcc/testsuite/g++.dg/opt/pr95528.C.jj 2020-06-05 13:13:17.137165849
>+0200
>+++ gcc/testsuite/g++.dg/opt/pr95528.C 2020-06-05 13:13:13.144224118
>+0200
>@@ -0,0 +1,27 @@
>+// PR target/95528
>+// { dg-do compile { target c++11 } }
>+// { dg-options "-O3" }
>+// { dg-additional-options "-march=skylake-avx512" { target i?86-*-*-
>x86_64-*-* } }
>+
>+template <typename a> struct b {
>+ typedef a c __attribute__((vector_size(sizeof(a) * 4)));
>+ union {
>+ c d;
>+ struct {
>+ a e, f, g, h;
>+ };
>+ };
>+ b();
>+ b(const b &i) : d(i.d) {}
>+ static b j(c);
>+ template <typename k> operator b<k>() {
>+ b<k>::j(typename b<k>::c{k(e), k(f), k(g), k(h)});
>+ return b<k>();
>+ }
>+};
>+template <typename a> using l = b<a>;
>+using m = l<char>;
>+using n = l<short>;
>+m o(n i) { return i; }
>+b<short> q;
>+void p() { o(q); }
>
> Jakub
