https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88897
Martin Sebor changed:
What|Removed |Added
Summary|Bogus maybe-uninitialized |[9/10/11 Regression] Bogus
|warning on class field |maybe-uninitialized warning
|(missed CSE)|on class field (missed CSE)
--- Comment #8 from Martin Sebor ---
The warning first appeared in r245840 (GCC 7.0.1 20170302), ironically
committed to fix PR tree-optimization/79345 (passing yet-uninitialized member
as argument to base class constructor should warn (-Wunitialized)). The IL
emitted just before that revision doesn't look all that different:
void foo() ()
{
struct future_stateD.2397 _local_stateD.2411;
struct future_stateD.2397 * _4;
charD.10 * _6;
voidD.45 * _7;
boolD.2220 _8;
;; basic block 2, loop depth 0, count 0, freq 1, maybe hot
;;prev block 0, next block 7, flags: (NEW, REACHABLE, VISITED)
;;pred: ENTRY [100.0%] (FALLTHRU,EXECUTABLE)
# .MEM_3 = VDEF <.MEM_2(D)>
# PT = nonlocal escaped null
# USE = nonlocal null { D.2411 } (escaped)
# CLB = nonlocal null { D.2411 } (escaped)
_4 = _Z3barvD.2407 ();
# .MEM_5 = VDEF <.MEM_3>
# USE = nonlocal null { D.2411 } (escaped)
# CLB = nonlocal null { D.2411 } (escaped)
_ZN12future_stateC1EvD.2402 (&_local_stateD.2411);
# .MEM_10 = VDEF <.MEM_5>
MEM[(struct &)&_local_stateD.2411] ={v} {CLOBBER};
# .MEM_11 = VDEF <.MEM_10>
MEM[(struct optionalD.2323 *)&_local_stateD.2411]._M_engagedD.2340 = 0;
# PT = nonlocal escaped null
_7 = &_4->valueD.2401;
if (_7 != 0B)
goto ; [73.26%]
else
goto ; [26.74%]
;;succ: 4 [73.3%] (TRUE_VALUE,EXECUTABLE)
;;7 [26.7%] (FALSE_VALUE,EXECUTABLE)
;; basic block 7, loop depth 0, count 0, freq 2674, maybe hot
;;prev block 2, next block 3, flags: (NEW)
;;pred: 2 [26.7%] (FALSE_VALUE,EXECUTABLE)
;;succ: 3 [100.0%] (FALLTHRU)
;; basic block 3, loop depth 0, count 0, freq 6044, maybe hot
;;prev block 7, next block 4, flags: (NEW, REACHABLE, VISITED)
;;pred: 7 [100.0%] (FALLTHRU)
;;8 [100.0%] (FALLTHRU)
# .MEM_17 = PHI <.MEM_11(7), .MEM_13(8)>
goto ; [100.00%]
;;succ: 6 [100.0%] (FALLTHRU,EXECUTABLE)
;; basic block 4, loop depth 0, count 0, freq 7326, maybe hot
;;prev block 3, next block 8, flags: (NEW, REACHABLE, VISITED)
;;pred: 2 [73.3%] (TRUE_VALUE,EXECUTABLE)
# .MEM_13 = VDEF <.MEM_11>
MEM[(struct optionalD.2323 *)_4]._M_engagedD.2340 = 0;
# VUSE <.MEM_13>
_8 = MEM[(struct optionalD.2323 &)&_local_stateD.2411]._M_engagedD.2340;
if (_8 != 0)
goto ; [54.00%]
else
goto ; [46.00%]
;;succ: 5 [54.0%] (TRUE_VALUE,EXECUTABLE)
;;8 [46.0%] (FALSE_VALUE,EXECUTABLE)
;; basic block 8, loop depth 0, count 0, freq 3370, maybe hot
;;prev block 4, next block 5, flags: (NEW)
;;pred: 4 [46.0%] (FALSE_VALUE,EXECUTABLE)
goto ; [100.00%]
;;succ: 3 [100.0%] (FALLTHRU)
;; basic block 5, loop depth 0, count 0, freq 3956, maybe hot
;;prev block 8, next block 6, flags: (NEW, REACHABLE, VISITED)
;;pred: 4 [54.0%] (TRUE_VALUE,EXECUTABLE)
# VUSE <.MEM_13>
# PT = nonlocal escaped null
_6 = MEM[(struct temporary_bufferD.2301 &)&_local_stateD.2411]._bufferD.2303;
# .MEM_15 = VDEF <.MEM_13>
MEM[(struct temporary_bufferD.2301 *)_4]._bufferD.2303 = _6;
# .MEM_16 = VDEF <.MEM_15>
MEM[(struct optionalD.2323 *)_4]._M_engagedD.2340 = 1;
;;succ: 6 [100.0%] (FALLTHRU,EXECUTABLE)
;; basic block 6, loop depth 0, count 0, freq 1, maybe hot
;;prev block 5, next block 1, flags: (NEW, REACHABLE, VISITED)
;;pred: 5 [100.0%] (FALLTHRU,EXECUTABLE)
;;3 [100.0%] (FALLTHRU,EXECUTABLE)
# .MEM_1 = PHI <.MEM_16(5), .MEM_17(3)>
# .MEM_9 = VDEF <.MEM_1>
_local_stateD.2411 ={v} {CLOBBER};
# VUSE <.MEM_9>
return;
;;succ: EXIT [100.0%]
}
