On Mon, Mar 20, 2017 at 8:15 PM, Bill Schmidt
<wschm...@linux.vnet.ibm.com> wrote:
> Hi,
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79908 shows a case where
> pass_stdarg ICEs attempting to gimplify a COMPLEX_EXPR with side
> effects as an lvalue. This occurs when the LHS of a VA_ARG has been
> cast away. This patch, credit to Richard Biener, uses
> force_gimple_operand to instantiate the necessary side effects rather
> than gimplify_expr using is_gimple_lvalue. The test case is taken
> wholesale from the bug report.
>
> Bootstrapped and tested on powerpc64le-unknown-linux-gnu with no
> regressions. Is this ok for trunk?
Ok!
Thanks,
Richard.
> Thanks,
> Bill
>
>
> [gcc]
>
> 2017-03-20 Bill Schmidt <wschm...@linux.vnet.ibm.com>
> Richard Biener <rgue...@suse.com>
>
> PR tree-optimization/79908
> * tree-stdarg.c (expand_ifn_va_arg_1): For a VA_ARG whose LHS has
> been cast away, use force_gimple_operand to construct the side
> effects.
>
> [gcc/testsuite]
>
> 2017-03-20 Bill Schmidt <wschm...@linux.vnet.ibm.com>
> Richard Biener <rguent...@suse.de>
>
> PR tree-optimization/79908
> * gcc.dg/torture/pr79908.c: New file.
>
>
> Index: gcc/testsuite/gcc.dg/torture/pr79908.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/torture/pr79908.c (nonexistent)
> +++ gcc/testsuite/gcc.dg/torture/pr79908.c (working copy)
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +
> +/* Used to fail in the stdarg pass before fix for PR79908. */
> +
> +typedef __builtin_va_list __gnuc_va_list;
> +typedef __gnuc_va_list va_list;
> +
> +void testva (int n, ...)
> +{
> + va_list ap;
> + _Complex int i = __builtin_va_arg (ap, _Complex int);
> +}
> Index: gcc/tree-stdarg.c
> ===================================================================
> --- gcc/tree-stdarg.c (revision 246286)
> +++ gcc/tree-stdarg.c (working copy)
> @@ -33,6 +33,7 @@ along with GCC; see the file COPYING3. If not see
> #include "gimple-iterator.h"
> #include "gimple-walk.h"
> #include "gimplify.h"
> +#include "gimplify-me.h"
> #include "tree-into-ssa.h"
> #include "tree-cfg.h"
> #include "tree-stdarg.h"
> @@ -1058,12 +1059,16 @@ expand_ifn_va_arg_1 (function *fun)
> gimplify_assign (lhs, expr, &pre);
> }
> else
> - gimplify_expr (&expr, &pre, &post, is_gimple_lvalue, fb_lvalue);
> + {
> + gimple_seq tmp_seq;
> + force_gimple_operand (expr, &tmp_seq, false, NULL_TREE);
> + gimple_seq_add_seq_without_update (&pre, tmp_seq);
> + }
>
> input_location = saved_location;
> pop_gimplify_context (NULL);
>
> - gimple_seq_add_seq (&pre, post);
> + gimple_seq_add_seq_without_update (&pre, post);
> update_modified_stmts (pre);
>
> /* Add the sequence after IFN_VA_ARG. This splits the bb right
> @@ -1072,11 +1077,10 @@ expand_ifn_va_arg_1 (function *fun)
> gimple_find_sub_bbs (pre, &i);
>
> /* Remove the IFN_VA_ARG gimple_call. It's the last stmt in the
> - bb. */
> + bb if we added any stmts. */
> unlink_stmt_vdef (stmt);
> release_ssa_name_fn (fun, gimple_vdef (stmt));
> gsi_remove (&i, true);
> - gcc_assert (gsi_end_p (i));
>
> /* We're walking here into the bbs which contain the expansion of
> IFN_VA_ARG, and will not contain another IFN_VA_ARG that needs
>
