> I get a bootstrap failure on x86 (verify_flow_info failed) with it.
It's actually pre-existing: it's PRE value-numbering a call that can make an
abnormal goto, hence the CFG mess in the end. The call is ECF_PURE but also
ECF_LOOPING_CONST_OR_PURE, so gimple_has_side_effects returns true and, in
turn, call_can_make_abnormal_goto . The bug is in can_value_number_call.
I can come up with two solutions:
- testing ECF_LOOPING_CONST_OR_PURE as well, like gimple_has_side_effects, or
- calling call_can_make_abnormal_goto explicitly.
The attached patch implements the former. With it, I could bootstrap and test
the stor-layout.c patch on our internal testsuite.
What do you think?
* stor-layout.c (bit_from_pos): Distribute conversion to bitsizetype
in a PLUS_EXPR byte offset.
* tree-ssa-pre.c (can_value_number_call): Return false if the call
has the ECF_LOOPING_CONST_OR_PURE flag.
--
Eric Botcazou
Index: stor-layout.c
===================================================================
--- stor-layout.c (revision 187435)
+++ stor-layout.c (working copy)
@@ -786,25 +786,29 @@ start_record_layout (tree t)
}
/* Return the combined bit position for the byte offset OFFSET and the
- bit position BITPOS. */
+ bit position BITPOS.
+
+ These functions operate on byte and bit positions present in FIELD_DECLs
+ and assume that these expressions result in no (intermediate) overflow.
+ This assumption is necessary to fold the expressions as much as possible,
+ so as to avoid creating artificially variable-sized types in languages
+ supporting variable-sized types like Ada. */
tree
bit_from_pos (tree offset, tree bitpos)
{
+ if (TREE_CODE (offset) == PLUS_EXPR)
+ offset = size_binop (PLUS_EXPR,
+ fold_convert (bitsizetype, TREE_OPERAND (offset, 0)),
+ fold_convert (bitsizetype, TREE_OPERAND (offset, 1)));
+ else
+ offset = fold_convert (bitsizetype, offset);
return size_binop (PLUS_EXPR, bitpos,
- size_binop (MULT_EXPR,
- fold_convert (bitsizetype, offset),
- bitsize_unit_node));
+ size_binop (MULT_EXPR, offset, bitsize_unit_node));
}
/* Return the combined truncated byte position for the byte offset OFFSET and
- the bit position BITPOS.
-
- These functions operate on byte and bit positions as present in FIELD_DECLs
- and assume that these expressions result in no (intermediate) overflow.
- This assumption is necessary to fold the expressions as much as possible,
- so as to avoid creating artificially variable-sized types in languages
- supporting variable-sized types like Ada. */
+ the bit position BITPOS. */
tree
byte_from_pos (tree offset, tree bitpos)
Index: tree-ssa-pre.c
===================================================================
--- tree-ssa-pre.c (revision 187435)
+++ tree-ssa-pre.c (working copy)
@@ -2592,10 +2592,15 @@ compute_antic (void)
static bool
can_value_number_call (gimple stmt)
{
+ int flags;
+
if (gimple_call_internal_p (stmt))
return false;
- if (gimple_call_flags (stmt) & (ECF_PURE | ECF_CONST))
+
+ flags = gimple_call_flags (stmt);
+ if ((flags & (ECF_PURE | ECF_CONST)) && !(flags & ECF_LOOPING_CONST_OR_PURE))
return true;
+
return false;
}
