https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96351
--- Comment #4 from Andrew Macleod <amacleod at redhat dot com> ---
=========== BB 5 ============
str_3(D) [irange] int [1, +INF]
Relational : (pszTmp_10 > str_3(D))
<bb 5> [local count: 310901944]:
pszTmp_10 = str_3(D) + 1;
goto <bb 7>; [100.00%]
pszTmp_10 : [irange] int [2, +INF] MASK 0x7fffffff VALUE 0x0
=========== BB 6 ============
Relational : (pszTmp_12 > pszTmp_11)
<bb 6> [local count: 2515479380]:
pszTmp_12 = pszTmp_11 + 1;
pszTmp_12 : [irange] int [3, +INF] MASK 0x7fffffff VALUE 0x0
=========== BB 7 ============
Imports: _13
Exports: _13
pszTmp_10 [irange] int [2, +INF] MASK 0x7fffffff VALUE 0x0
Equivalence set : [pszTmp_11]
<bb 7> [local count: 2826381324]:
# pszTmp_11 = PHI <pszTmp_10(5), pszTmp_12(6)>
_13 = f (pszTmp_11);
if (_13 != 0)
goto <bb 6>; [89.00%]
else
goto <bb 8>; [11.00%]
pszTmp_11 : [irange] int [2, +INF] MASK 0x7fffffff VALUE 0x0
7->6 (T) _13 : [irange] int [-INF, -1][1, +INF]
7->8 (F) _13 : [irange] int [0, 0]
at the PHI npde:
# pszTmp_11 = PHI <pszTmp_10(5), pszTmp_12(6)>
We know (pszTmp_10 > str_3(D)) coming in from bb5.
we know (pszTmp_12 > pszTmp_11) from bb6
What we dont currently do is create relations for a PHI def from what we can
learn from the arguments.
we could determine that pszTmp_11 is increasing in value from bb6 since that
argument is > pszTmp_11.
and with argument 1 being the initial value of the increasing value, we could
transitively conclude pszTmp_11 > str_3(D) as well.
=========== BB 8 ============
Imports: str_3(D) pszTmp_8
Exports: str_3(D) pszTmp_8
str_3(D) [irange] int [1, +INF]
Equivalence set : [pszTmp_8, pszTmp_11]
<bb 8> [local count: 310901944]:
# pszTmp_8 = PHI <pszTmp_11(7)>
if (str_3(D) == pszTmp_8)
goto <bb 3>; [1.49%]
else
goto <bb 9>; [98.51%]
pszTmp_8 is in an equivlaence with pszTmp_11, so we would then elimiate the
comparison.
This is related to 116753... we need to do some relation applications to the
PHI def based on arguments.
