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* [Bug tree-optimization/91881] Value range knowledge of higher bits not used in optimizations
[not found] <bug-91881-4@http.gcc.gnu.org/bugzilla/>
@ 2021-08-01 17:37 ` pinskia at gcc dot gnu.org
0 siblings, 0 replies; only message in thread
From: pinskia at gcc dot gnu.org @ 2021-08-01 17:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91881
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|middle-end |tree-optimization
Severity|normal |enhancement
Last reconfirmed|2019-09-25 00:00:00 |2021-8-1
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
unsigned long long sample2(unsigned long long m) {
if (((unsigned int)m) != m) __builtin_unreachable();
m <<= 4;
return m >> 3;
}
unsigned long long sample1(unsigned long long m) {
if (((unsigned int)m) != m) __builtin_unreachable();
unsigned long t = -1;
t <<= 1;
m <<= 4;
return (m >> 3) & t;
}
unsigned long long sample(unsigned long long m) {
if (m >= 100) __builtin_unreachable();
return m << 1;
}
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[not found] <bug-91881-4@http.gcc.gnu.org/bugzilla/>
2021-08-01 17:37 ` [Bug tree-optimization/91881] Value range knowledge of higher bits not used in optimizations pinskia at gcc dot gnu.org
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