Hi,
this patch adds missing profile update to maybe_optimize_range_tests.
Jakub, I hope I got the code right: I think it basically analyzes the
chain of conditionals, finds some basic blocks involved in the range
testing and then puts all the test into first BB.
The patch fixes gcc.dg/tree-ssa/update-threading.c profile misupdate on
power-pc. Curiously enough the code is produced differently for x86_64.
I tried to find testcase for x86_64 and found that
testsuite/gcc.dg/tree-ssa/reassoc-33.c
testsuite/gcc.dg/tree-ssa/reassoc-37.c
testsuite/gcc.dg/tree-ssa/reassoc-43.c
are testing this function. However sadly neighter of these testcases seems
to work as expected. For example in testsuite/gcc.dg/tree-ssa/reassoc-33.c
we turn
;; basic block 3, loop depth 0, count 708669600 (estimated locally, freq
0.6600), maybe hot
;; prev block 2, next block 4, flags: (NEW, VISITED)
;; pred: 2 [66.0% (guessed)] count:708669600 (estimated locally, freq
0.6600) (FALSE_VALUE,EXECUTABLE)
_4 = a_14(D) == 44;
_5 = a_14(D) == 78;
_30 = 0;
_6 = _4 | _5;
if (_30 != 0)
goto ; [34.00%]
else
goto ; [66.00%]
;; succ: 7 [34.0% (guessed)] count:240947667 (estimated locally, freq
0.2244) (TRUE_VALUE,EXECUTABLE)
;; 4 [66.0% (guessed)] count:467721933 (estimated locally, freq
0.4356) (FALSE_VALUE,EXECUTABLE)
to
;; basic block 2, loop depth 0, count 1073741824 (estimated locally, freq
1.), maybe hot
;; prev block 0, next block 3, flags: (NEW, VISITED)
;; pred: ENTRY [always] count:1073741824 (estimated locally, freq
1.) (FALLTHRU,EXECUTABLE)
_18 = (unsigned int) a_14(D);
_19 = _18 + 4294967253;
_24 = (unsigned int) a_14(D);
_25 = _24 + 4294967253;
_26 = _25 & 4294967260;
_27 = _26 == 0;
_20 = _19 <= 3;
_1 = a_14(D) == 43;
_21 = (unsigned int) a_14(D);
_22 = _21 + 4294967221;
_23 = _22 <= 3;
_2 = a_14(D) == 75;
_31 = _27;
_3 = _1 | _2;
if (_31 != 0)
goto ; [34.00%]
else
goto ; [66.00%]
which replaces later tests
;; basic block 4, loop depth 0, count 467721934 (estimated locally, freq
0.4356), maybe hot
;; prev block 3, next block 5, flags: (NEW, VISITED)
;; pred: 3 [66.0% (guessed)] count:467721933 (estimated locally, freq
0.4356) (FALSE_VALUE,EXECUTABLE)
_7 = a_14(D) == 77;
_8 = a_14(D) == 46;
_29 = 0;
_9 = _7 | _8;
if (_29 != 0)
goto ; [34.00%]
else
goto ; [66.00%]
;; basic block 5, loop depth 0, count 308696475 (estimated locally, freq
0.2875), maybe hot
;; prev block 4, next block 6, flags: (NEW, VISITED)
;; pred: 4 [66.0% (guessed)] count:308696475 (estimated locally, freq
0.2875) (FALSE_VALUE,EXECUTABLE)
_10 = a_14(D) == 76;
_11 = a_14(D) == 45;
_28 = 0;
_12 = _10 | _11;
if (_28 != 0)
goto ; [50.00%]
else
goto ; [50.00%]
;; succ: 7 [50.0% (guessed)] count:154348238 (estimated locally, freq
0.1437) (TRUE_VALUE,EXECUTABLE)
;; 6 [50.0% (guessed)] count:154348238 (estimated locally, freq
0.1437) (FALSE_VALUE,EXECUTABLE)
However BB4 and BB5 is not updated to be unconditional by tree-ssa-reassoc pass
and we thus miss the profile update.
This happens later in forwprop but at that time it is too late to update the
probabilities.
So we get:
;; basic block 2, loop depth 0, count 1073741824 (estimated locally, freq
1.), maybe hot
;;prev block 0, next block 3, flags: (NEW, VISITED)
;;pred: ENTRY [always] count:1073741824 (estimated locally, freq
1.) (FALLTHRU,EXECUTABLE)
_24 = (unsigned int) a_14(D);
_25 = _24 + 4294967253;
_26 = _25 & 4294967260;
_27 = _26 == 0;
if (_26 == 0)
goto ; [34.00%]
else
goto ; [66.00%]
;;succ: 4 [34.0% (guessed)] count:365072224 (estimated locally, freq
0.3400) (TRUE_VALUE,EXECUTABLE)
;;3 [66.0% (guessed)] count:708669600 (estimated locally, freq
0.6600) (FALSE_VALUE,EXECUTABLE)
;; basic block 3, loop depth 0, count 154348237 (estimated locally, freq
0.1437), maybe hot
;; Invalid sum of incoming counts 708669600 (estimated locally, freq 0.6600),
should be 154348237 (estimated locally, freq 0.1437)
;;prev block 2, next block 4, flags: (NEW, VISITED)
;;pred: 2 [66.0% (guessed)] count:708669600 (estimated locally, freq
0.6600) (FALSE_VALUE,EXECUTABLE)
;;succ: 4 [always] count:154348237 (estimated locally, freq 0.1437)
(FALLTHRU,EXECUTABLE) c.c:12:12
;; basic block 4, loop depth 0, count 1073741824 (estimated locally, freq
1.), maybe hot
;; Invalid sum of incoming counts 519420461 (estimated locally, freq 0.4837),
should be 1073741824 (estimated locally, freq 1.)
;;prev block 3, next block 1, flags: (NEW, VISITED)
;;pred: 2 [34.0% (guessed)] count:365072224 (estimated locally, freq
0.3400) (TRUE_VALUE,EXECUTABLE)
;;3 [always] count:154348237 (estimated locally, freq 0.1437)
(FALLTHRU,EXECUTABLE) c.c:12:12
# _13 = PHI
return _13;
Jakub, it seems that the code is originally yours. Any idea why those are not
turned to
constant true
