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. The previous patch (reverted) used force_gimple_operand
to instantiate the necessary side effects rather than gimplify_expr
using is_gimple_lvalue. This proved to cause problems on some targets
where the gimple expression produced by targetm.gimplify_va_arg_expr
contains un-gimplified side effects using raw var_decls (see
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80136). After some
investigation, the right fix seems to be to just call
gimplify_and_add on the expression.
I've bootstrapped and tested this on powerpc64le-unknown-linux-gnu
with no regressions. I've also built a ppc64le->aarch64 cross and
verified that Christophe's original report from PR80136 is now
fixed. I don't have immediate access to an aarch64 native system
(compile farm authentication issues), so I would appreciate it if
James could run a native bootstrap to see if his issues are
resolved.
Provided there are no issues uncovered with aarch64 native bootstrap,
is this ok for trunk?
Thanks,
Bill
[gcc]
2017-03-21 Bill Schmidt <wschm...@linux.vnet.ibm.com>
Richard Biener <rgue...@suse.com>
PR tree-optimization/79908
PR tree-optimization/80136
* tree-stdarg.c (expand_ifn_va_arg_1): For a VA_ARG whose LHS has
been cast away, gimplify_and_add suffices.
[gcc/testsuite]
2017-03-21 Bill Schmidt <wschm...@linux.vnet.ibm.com>
Richard Biener <rguent...@suse.de>
PR tree-optimization/79908
PR tree-optimization/80136
* gcc.dg/torture/pr79908.c: New file.
Index: gcc/testsuite/gcc.dg/torture/pr79908.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr79908.c (revision 246334)
+++ 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 246334)
+++ gcc/tree-stdarg.c (working copy)
@@ -1058,7 +1058,7 @@ expand_ifn_va_arg_1 (function *fun)
gimplify_assign (lhs, expr, &pre);
}
else
- gimplify_expr (&expr, &pre, &post, is_gimple_lvalue, fb_lvalue);
+ gimplify_and_add (expr, &pre);
input_location = saved_location;
pop_gimplify_context (NULL);
