Thanks for doing this.
Matthew Beliveau <mbeli...@redhat.com> writes:
> diff --git gcc/tree-ssa-dse.c gcc/tree-ssa-dse.c
> index 5b7c4fc6d1a..dcaeb8edbfe 100644
> --- gcc/tree-ssa-dse.c
> +++ gcc/tree-ssa-dse.c
> @@ -628,11 +628,8 @@ dse_optimize_redundant_stores (gimple *stmt)
> tree fndecl;
> if ((is_gimple_assign (use_stmt)
> && gimple_vdef (use_stmt)
> - && ((gimple_assign_rhs_code (use_stmt) == CONSTRUCTOR
> - && CONSTRUCTOR_NELTS (gimple_assign_rhs1 (use_stmt)) == 0
> - && !gimple_clobber_p (stmt))
> - || (gimple_assign_rhs_code (use_stmt) == INTEGER_CST
> - && integer_zerop (gimple_assign_rhs1 (use_stmt)))))
> + && initializer_zerop (gimple_op (use_stmt, 1), NULL)
> + && !gimple_clobber_p (stmt))
> || (gimple_call_builtin_p (use_stmt, BUILT_IN_NORMAL)
> && (fndecl = gimple_call_fndecl (use_stmt)) != NULL
> && (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_MEMSET
> @@ -1027,15 +1024,13 @@ dse_dom_walker::dse_optimize_stmt
> (gimple_stmt_iterator *gsi)
> {
> bool by_clobber_p = false;
>
> - /* First see if this store is a CONSTRUCTOR and if there
> - are subsequent CONSTRUCTOR stores which are totally
> - subsumed by this statement. If so remove the subsequent
> - CONSTRUCTOR store.
> + /* Check if this store initalizes zero, or some aggregate of zeros,
> + and check if there are subsequent stores which are subsumed by this
> + statement. If so, remove the subsequent store.
>
> This will tend to make fewer calls into memset with longer
> arguments. */
> - if (gimple_assign_rhs_code (stmt) == CONSTRUCTOR
> - && CONSTRUCTOR_NELTS (gimple_assign_rhs1 (stmt)) == 0
> + if (initializer_zerop (gimple_op (stmt, 1), NULL)
> && !gimple_clobber_p (stmt))
> dse_optimize_redundant_stores (stmt);
>
In addition to Jeff's comment, the original choice of gimple_assign_rhs1
is the preferred way to write this (applies to both hunks).
Richard
