Re: [PATCH] tree-optimization/98221 - fix wrong unpack operation used for big-endian

[Jeff Law via Gcc-patches]

On 1/11/21 3:02 AM, Andreas Krebbel via Gcc-patches wrote:
> The vec-abi-varargs-1.c testcase on IBM Z currently fails.
>
> While adding an SI mode vector to a DI mode vector the first is unpacked 
> using:
>
>   _28 = BIT_INSERT_EXPR <{ 0, 0, 0, 0 }, _2, 0>;
>   _34 = [vec_unpack_lo_expr] _28;
>
> However, on big endian targets lo refers to the right hand side of the vector 
> - in this case the zeroes.
>
> Bootstrap & regtest running on x86_64-unknown-linux-gnu.
>
> 2021-01-11  Andreas Krebbel  
>
>   * tree-ssa-forwprop.c (simplify_vector_constructor): For
>   big-endian, use UNPACK[_FLOAT]_HI.
OK
jeff

[PATCH] tree-optimization/98221 - fix wrong unpack operation used for big-endian

[Andreas Krebbel via Gcc-patches]

The vec-abi-varargs-1.c testcase on IBM Z currently fails.

While adding an SI mode vector to a DI mode vector the first is unpacked using:

  _28 = BIT_INSERT_EXPR <{ 0, 0, 0, 0 }, _2, 0>;
  _34 = [vec_unpack_lo_expr] _28;

However, on big endian targets lo refers to the right hand side of the vector - 
in this case the zeroes.

Bootstrap & regtest running on x86_64-unknown-linux-gnu.

2021-01-11  Andreas Krebbel  

* tree-ssa-forwprop.c (simplify_vector_constructor): For
big-endian, use UNPACK[_FLOAT]_HI.
---
 gcc/tree-ssa-forwprop.c | 21 +
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c
index 8a1a1237647..0706fd862de 100644
--- a/gcc/tree-ssa-forwprop.c
+++ b/gcc/tree-ssa-forwprop.c
@@ -2392,6 +2392,17 @@ simplify_vector_constructor (gimple_stmt_iterator *gsi)
 some simple special cases via VEC_[UN]PACK[_FLOAT]_LO_EXPR.  */
  optab optab;
  tree halfvectype, dblvectype;
+ enum tree_code unpack_op;
+
+ if (!BYTES_BIG_ENDIAN)
+   unpack_op = (FLOAT_TYPE_P (TREE_TYPE (type))
+? VEC_UNPACK_FLOAT_LO_EXPR
+: VEC_UNPACK_LO_EXPR);
+ else
+   unpack_op = (FLOAT_TYPE_P (TREE_TYPE (type))
+? VEC_UNPACK_FLOAT_HI_EXPR
+: VEC_UNPACK_HI_EXPR);
+
  if (CONVERT_EXPR_CODE_P (conv_code)
  && (2 * TYPE_PRECISION (TREE_TYPE (TREE_TYPE (orig[0])))
  == TYPE_PRECISION (TREE_TYPE (type)))
@@ -2405,9 +2416,7 @@ simplify_vector_constructor (gimple_stmt_iterator *gsi)
 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,
+ && (optab = optab_for_tree_code (unpack_op,
   dblvectype,
   optab_default))
  && (optab_handler (optab, TYPE_MODE (dblvectype))
@@ -2430,11 +2439,7 @@ simplify_vector_constructor (gimple_stmt_iterator *gsi)
orig[0], TYPE_SIZE (dblvectype),
bitsize_zero_node);
  gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
- gimple_assign_set_rhs_with_ops (gsi,
- FLOAT_TYPE_P (TREE_TYPE (type))
- ? VEC_UNPACK_FLOAT_LO_EXPR
- : VEC_UNPACK_LO_EXPR,
- dbl);
+ gimple_assign_set_rhs_with_ops (gsi, unpack_op, dbl);
}
  else if (CONVERT_EXPR_CODE_P (conv_code)
   && (TYPE_PRECISION (TREE_TYPE (TREE_TYPE (orig[0])))
-- 
2.26.2