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* [Bug tree-optimization/82854] more missing simplifcations
[not found] <bug-82854-4@http.gcc.gnu.org/bugzilla/>
@ 2021-08-07 6:44 ` pinskia at gcc dot gnu.org
2021-08-07 7:03 ` pinskia at gcc dot gnu.org
2023-05-02 5:24 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-07 6:44 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82854
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |missed-optimization
Severity|normal |enhancement
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/82854] more missing simplifcations
[not found] <bug-82854-4@http.gcc.gnu.org/bugzilla/>
2021-08-07 6:44 ` [Bug tree-optimization/82854] more missing simplifcations pinskia at gcc dot gnu.org
@ 2021-08-07 7:03 ` pinskia at gcc dot gnu.org
2023-05-02 5:24 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-07 7:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82854
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Last reconfirmed| |2021-08-07
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Summary of some of these
/* x + (x & 0x80000000) -> x & 0x7fffffff */
No one does
/* (x | 0x80000000) + 0x80000000 -> x & 0x7FFFFFFF */
LLVM does
/* x & (0x7FFFFFFF - x) -> x & 0x80000000 */
No one does, ICC does (-x + 0x7FFFFFFF) & x
/* x | (x + 0x80000000) -> x | 0x80000000 */
LLVM does
/* x | (0x7FFFFFFF - x) -> x | 0x7FFFFFFF */
No one does, ICC does (-x + 0x7FFFFFFF) | x
/* x | (x ^ y) -> x | y */
GCC and LLVM
/* -x | 0xFFFFFFFE -> x | 0xFFFFFFFE */
LLVM does
/* 0 - (x & 0x80000000) -> x & 0x80000000 */
LLVM does
/* ~(x + c) -> ~c - x */
GCC and LLVM
/* (x | c) - c -> x & ∼c */
GCC and LLVM
/* 0x7FFFFFFF - (x ^ c) -> x ^ (0x7FFFFFFF - c) */
LLVM does
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/82854] more missing simplifcations
[not found] <bug-82854-4@http.gcc.gnu.org/bugzilla/>
2021-08-07 6:44 ` [Bug tree-optimization/82854] more missing simplifcations pinskia at gcc dot gnu.org
2021-08-07 7:03 ` pinskia at gcc dot gnu.org
@ 2023-05-02 5:24 ` pinskia at gcc dot gnu.org
2 siblings, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-05-02 5:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82854
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
> /* 0 - (x & 0x80000000) -> x & 0x80000000 */
> LLVM does
Actually RTL has done this since at least GCC 4.1.0, most likely before.
^ permalink raw reply [flat|nested] 3+ messages in thread
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[not found] <bug-82854-4@http.gcc.gnu.org/bugzilla/>
2021-08-07 6:44 ` [Bug tree-optimization/82854] more missing simplifcations pinskia at gcc dot gnu.org
2021-08-07 7:03 ` pinskia at gcc dot gnu.org
2023-05-02 5:24 ` pinskia at gcc dot gnu.org
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