https://gcc.gnu.org/bugzilla/show_bug.cgi?id=10837
gooncreeper changed:
What|Removed |Added
CC||goon.pri.low at gmail dot com
--- Comment
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112928
Bug ID: 112928
Summary: missed-optimization: automatic storage address
comparisons
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112662
--- Comment #2 from gooncreeper ---
I believe I got my initial optimized function wrong, it should actually be this
unsigned opt(unsigned a) {
if (++a > 999) a = 0;
return a;
}
opt:
lea eax, [rdi+1]
xor edx,
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112660
--- Comment #1 from gooncreeper ---
This could be further extended for signed integers as we can assume for left
shifts that shifted out bits are always 0 else UB, and always combine x << a >>
b.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112687
Bug ID: 112687
Summary: missed-optimization: switch statement does not
simplify to it's expression
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112685
Bug ID: 112685
Summary: missed-optimization: division / modulo loops
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112645
--- Comment #2 from gooncreeper ---
I am going to move the second problem to it's own bug since I realize it
actually quite a different problem, and deserves it's own thread of discussion.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112685
--- Comment #2 from gooncreeper ---
(In reply to Andrew Pinski from comment #1)
> I thought I had saw this a while back.
>
> Note the Linux kernel does this kind of loop explicity to avoid the division
> though as the cases where it does is
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112608
Bug ID: 112608
Summary: Missed-optimization: Multiple Division Constants
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112629
Bug ID: 112629
Summary: Missed-optimization: constant << (b + signed_constant)
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112629
--- Comment #3 from gooncreeper ---
This optimization could also be performed for unsigned integers if we know they
won't overflow in the optimization.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112645
Bug ID: 112645
Summary: missed-optimization: cswitch optimization missed in
nested if-statement
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112657
Bug ID: 112657
Summary: missed optimization: cmove not used with multiple
returns
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112659
Bug ID: 112659
Summary: missed-optimization: if (exp) return exp; else return
0;
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112660
Bug ID: 112660
Summary: missed-optimization: combine shifts when shifted out
bits are known 0
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112659
--- Comment #4 from gooncreeper ---
(In reply to Andrew Pinski from comment #2)
> >Note: this happens for all operators, not just addition!
>
> Actually it is just addition with a constant on the trunk.
> ```
> int g(int v, int b) {
> if
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112662
Bug ID: 112662
Summary: missed-optimization: loop increment until wrap
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112663
Bug ID: 112663
Summary: missed-optimization: sum of 1 to n
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112664
Bug ID: 112664
Summary: missed-optimization: extra comparison when reordering
statements
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112664
--- Comment #2 from gooncreeper ---
(In reply to Andrew Pinski from comment #1)
> Dup.
>
> *** This bug has been marked as a duplicate of bug 105496 ***
Apologies.
Though, how are you so good at finding duplicates? What's the secret?
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112664
--- Comment #4 from gooncreeper ---
(In reply to Andrew Pinski from comment #1)
> Dup.
>
> *** This bug has been marked as a duplicate of bug 105496 ***
Apologies.
Though, how are you so good at finding duplicates? What's the secret?(In reply
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114538
Bug ID: 114538
Summary: constant fold for (v + 1 == 0) == (v + 1 < v) fails
when v + 1 is stored in variable
Product: gcc
Version: 14.0
Status: UNCONFIRMED
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114547
Bug ID: 114547
Summary: missed-optimization: use sign flag
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114547
--- Comment #2 from gooncreeper ---
(In reply to Andrew Pinski from comment #1)
> I am not sure this is always better ...
sets and setns are 1 uop, just like any other setcc
why wouldn't it be better?
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114524
Bug ID: 114524
Summary: Use less expensive expression when expressions are
equal
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114669
Bug ID: 114669
Summary: use >= comparison when testing high bits
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component:
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