Hi,
Could a gatekeep please help review on fix for bug869?
http://bugs.open64.net/show_bug.cgi?id=869
symptom:
opencc builds broken for this case:
int g = 0x10;
int *volatile h = &g;
int f(){
while (1)
if (*h) continue;
}
Analysis:
after goto convertion, we get whirl program:
LABEL L1794 0 {line: 0/0}
U8U8LDID 0 <1,51,h> T<53,anon_ptr.,8,V>
I4I4ILOAD 0 T<4,.predef_I4,4> T<53,anon_ptr.,8>
U4INTCONST 0 (0x0)
I4I4NE
TRUEBR L514 {line: 1/6}
LABEL L514 0 {line: 1/6}
GOTO L1794 {line: 0/0}
when it goes to the CFG construction phase, the label(L514) bb happens to
the fallthrough bb of TRUEBR bb(_current_bb), so no real branch case
generated.
Solution:
Add null bb for this case.
Patch:
--- a/osprey/be/opt/opt_cfg.cxx
+++ b/osprey/be/opt/opt_cfg.cxx
@@ -3189,6 +3189,19 @@ CFG::Add_one_stmt( WN *wn, END_BLOCK *ends_bb )
("Non-empty block assigned to a label") );
// if we're trying to add this label to a non-empty block, we
// need to end the current block, and connect the new one to it
+
+ // fix bug869(open64.net), check to see whether last statement of
_current_bb
+ // is OPR_FALSEBR/OPR_TRUEBR, and the statment's label bb is
label_bb.
+ // if so, add the null fall-through bb and set it be the current bb
+ WN* last_wn_current_bb=_current_bb->Laststmt();
+ if (last_wn_current_bb &&
+ (OPCODE_operator(WN_opcode(last_wn_current_bb)) == OPR_FALSEBR
||
+ OPCODE_operator(WN_opcode(last_wn_current_bb)) == OPR_TRUEBR)
&&
+ Get_bb_from_label( WN_label_number(last_wn_current_bb)) ==
label_bb) {
+ BB_NODE* fall_through_bb= Create_bb();
+ Connect_predsucc(_current_bb,fall_through_bb);
+ Append_bb(fall_through_bb);
+ }
if ( ! _current_bb->Hasujp() )
Connect_predsucc( _current_bb, label_bb );
Regards
Gang
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