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* [Bug tree-optimization/87987] Missed optimization with ranged-for loop on a constexpr array
[not found] <bug-87987-4@http.gcc.gnu.org/bugzilla/>
@ 2021-12-17 4:22 ` pinskia at gcc dot gnu.org
2021-12-17 4:27 ` pinskia at gcc dot gnu.org
2021-12-17 4:29 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-17 4:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87987
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
Component|c++ |tree-optimization
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/87987] Missed optimization with ranged-for loop on a constexpr array
[not found] <bug-87987-4@http.gcc.gnu.org/bugzilla/>
2021-12-17 4:22 ` [Bug tree-optimization/87987] Missed optimization with ranged-for loop on a constexpr array pinskia at gcc dot gnu.org
@ 2021-12-17 4:27 ` pinskia at gcc dot gnu.org
2021-12-17 4:29 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-17 4:27 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87987
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So I think LLVM's unrolling notices the load will become constant and the whole
induction variable basically goes away for sum.
Even for this C code LLVM does the optimization:
static const int table[] = { 1,10,10, 1, 1,10, 1,10 , 1,10,10, 1, 1,10, 1,10 ,
1,10,10, 1, 1,10, 1,10 , 1,10,10, 1, 1,10, 1,10 };
int check1()
{
int sum = 1;
for (unsigned long i = 0; i < sizeof(table)/sizeof(table[0]);i++)
sum += table[i];
return sum;
}
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/87987] Missed optimization with ranged-for loop on a constexpr array
[not found] <bug-87987-4@http.gcc.gnu.org/bugzilla/>
2021-12-17 4:22 ` [Bug tree-optimization/87987] Missed optimization with ranged-for loop on a constexpr array pinskia at gcc dot gnu.org
2021-12-17 4:27 ` pinskia at gcc dot gnu.org
@ 2021-12-17 4:29 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-17 4:29 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87987
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |DUPLICATE
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Dup of bug 87543.
*** This bug has been marked as a duplicate of bug 87543 ***
^ permalink raw reply [flat|nested] 3+ messages in thread
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[not found] <bug-87987-4@http.gcc.gnu.org/bugzilla/>
2021-12-17 4:22 ` [Bug tree-optimization/87987] Missed optimization with ranged-for loop on a constexpr array pinskia at gcc dot gnu.org
2021-12-17 4:27 ` pinskia at gcc dot gnu.org
2021-12-17 4:29 ` pinskia at gcc dot gnu.org
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