https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115034
--- Comment #2 from XChy ---
(In reply to Andrew Pinski from comment #1)
> Note there is some memory model requirements here that I always forget if
> this can happen or not.
Hmm. Could you please provide some documents about the memory model
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115035
Bug ID: 115035
Summary: Missed optimization: fold min/max in phi
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115034
Bug ID: 115034
Summary: Missed optimization: reduntant store of identical
value in the slot
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114797
--- Comment #2 from XChy ---
It looks like for completely overlapped memset, it's merged:
https://godbolt.org/z/4r7Eqr1Ee
With clobber, that's not the case: https://godbolt.org/z/8jhaEbKqo
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114797
Bug ID: 114797
Summary: Missed optimization : fail to merge memset with
unrelated clobber
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114737
Bug ID: 114737
Summary: Missed optimization : fail to optimize load with
select clobber
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114725
Bug ID: 114725
Summary: Missed optimization: more precise range for and
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114712
Bug ID: 114712
Summary: Missed optimization: simplify if-else basic blocks
that share common destinations
Product: gcc
Version: 14.0
Status: UNCONFIRMED
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114711
--- Comment #3 from XChy ---
(In reply to Andrew Pinski from comment #1)
> Note the openssl code issue was reported in pr 114682
Oh, thanks for transferring this LLVM issue! And because I'm recently trying to
transfer some of my LLVM issues to
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114711
Bug ID: 114711
Summary: Missed optimization: fold load of global constant
array if there is obivous pattern
Product: gcc
Version: 14.0
Status: UNCONFIRMED
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114704
--- Comment #3 from XChy ---
(In reply to Andrew Pinski from comment #1)
> Confirmed. A more general testcase:
> ```
> void dummy();
>
> void src(int *p, int a){
> int t = *p;
> if(t == a)
> goto then;
> else {
>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114704
Bug ID: 114704
Summary: Missed optimization : eliminate store if the value is
known in all predecessors
Product: gcc
Version: 14.0
Status: UNCONFIRMED
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114702
Bug ID: 114702
Summary: Missed optimization: fail to infer c - b != if a + b
!= c
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114331
Bug ID: 114331
Summary: Missed optimization: indicate knownbits from
dominating condition switch(trunc(a))
Product: gcc
Version: 14.0
Status: UNCONFIRMED
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113487
--- Comment #2 from XChy ---
I may miss something here... Apart from this one, it seems that GCC doesn't
simplify **one-use** instruction based on demanded bits too:
https://godbolt.org/z/67bYxd8hY
But LLVM indeed handle the one-use case.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113487
Bug ID: 113487
Summary: Missed optimization:simplify demanded bits on
multi-use instructions like select
Product: gcc
Version: 14.0
Status: UNCONFIRMED
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113105
--- Comment #5 from XChy ---
(In reply to Jakub Jelinek from comment #4)
> So, e.g. on x86_64,
> unsigned int
> f1 (unsigned val)
> {
> return val / 10 * 16 + val % 10;
> }
>
> unsigned int
> f2 (unsigned val)
> {
> return val / 10 * 6 +
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113071
XChy changed:
What|Removed |Added
CC||xxs_chy at outlook dot com
--- Comment #1 from
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113105
--- Comment #2 from XChy ---
(In reply to Jakub Jelinek from comment #1)
> When it is signed v / a * b + v % a, I think it can introduce UB which
> wasn't there originally.
> E.g. for v = 0, a = INT_MIN and b = 3. So, if it isn't done just for
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113105
Bug ID: 113105
Summary: Missing optimzation: fold `div(v, a) * b + rem(v, a)`
to `div(v, a) * (b - a) + v`
Product: gcc
Version: 14.0
Status: UNCONFIRMED
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112982
Bug ID: 112982
Summary: Missing optimization: fold max(b, a + 1) to b when a <
b
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112900
Bug ID: 112900
Summary: Missing optimization: canonicalize `select c, x - 1, x
+ 1` to `x + (select c, -1, 1)` (or reversely)
Product: gcc
Version: 14.0
Status:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112884
Bug ID: 112884
Summary: Missing optimization: fold a%2==0 ? a/2*2 : 0 to
a%2==0 ? a : 0
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112857
--- Comment #3 from XChy ---
(In reply to Richard Biener from comment #2)
> careful about overflow.
I'm not a developer of GCC, but for "(b + ~a) > 0 -> a - b ＜ -1", I can say
it's a valid refinement for both signed and unsigned, with SMT
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112857
--- Comment #4 from XChy ---
(In reply to Andrew Pinski from comment #1)
> For the above, GCC is able to get the best code for g0, g10, g1, and g4
> (though g1 and g4 are still `(b-a) > 0` at the gimple level. While LLVM is
> able to get it
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112857
Bug ID: 112857
Summary: Missing optimzation: fold (b + ~a) > 0 to a - b ＜ -1
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
26 matches
Mail list logo
