On Fri, Nov 7, 2014 at 11:22 AM, Jiong Wang <jiong.w...@arm.com> wrote:
> the problem is caused by constant fold of node with TREE_CLOBBER_P be true.
>
> according to rtl expander, the purpose of clobber is to mark the going out
> of scope.
>
> if (TREE_CLOBBER_P (rhs))
> /* This is a clobber to mark the going out of scope for
> this LHS. */
>
> for vshuf-v16hi, there will be such node
>
> <bb 5>:
> r ={v} {CLOBBER};
>
> while the new added "fold_all_stmts" since r216728 will invoke generic
> "fold"
> and that function in fold-const.c has a bug when folding CONSTRUCTOR. we
> should not do
> fold if the tree node is also with TREE_THIS_VOLATILE (t) be true, otherwise
> we will
> generate extra insn during expand.
>
> for example, above assignment will be transformed into
>
> r = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
>
> while OImode immediate move is not supported when "-mcpu=cortex-a9
> -mfloat-abi=softfp -mfpu=neon" specified,
> thus trigger "insn_invalid_p" error for this testcase.
>
> bootstrap ok on x86-64, no regression.
> ICE on arm gone away.
>
> ok to trunk?
Please instead guard the GIMPLE_SINGLE_RHS case in fold_gimple_assign
instead, like
Index: gcc/gimple-fold.c
===================================================================
--- gcc/gimple-fold.c (revision 217213)
+++ gcc/gimple-fold.c (working copy)
@@ -320,6 +320,9 @@
{
tree rhs = gimple_assign_rhs1 (stmt);
+ if (TREE_CLOBBER_P (rhs))
+ return NULL_TREE;
+
if (REFERENCE_CLASS_P (rhs))
return maybe_fold_reference (rhs, false);
ok with that change. If you like you can guard fold () as well, but please
inside the case CONSTRUCTOR: case only.
Thanks,
Richard.
> gcc/
> PR tree/63676
> fold-const.c (fold): Do not fold node when TREE_CLOBBER_P be true.
