On 07/11/14 10:35, Richard Biener wrote:
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.
But TREE_CLOBBER_P () checks for CONSTRUCTOR anyway. Does it have a
chance of being folded between the start of fold () and the case
CONSTRUCTOR: given its a CLOBBER? What am I missing?
Thanks,
Tejas.
