[Bug tree-optimization/99068] Missed PowerPC lhau optimization

2021-02-16 Thread brian.grayson at sifive dot com via Gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99068 --- Comment #9 from Brian Grayson --- If I understand correctly, you're saying that it is sometimes preferred for gcc to avoid update form, but even when the load and addi are next to each other it's possible to use update form, like in the examp

[Bug tree-optimization/99068] Missed PowerPC lhau optimization

2021-02-16 Thread segher at gcc dot gnu.org via Gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99068 --- Comment #8 from Segher Boessenkool --- Using update form instructions constrains register allocation and scheduling. It is *not* always a good idea. That is one of the reasons why we currently use update form instructions only when insns jus

[Bug tree-optimization/99068] Missed PowerPC lhau optimization

2021-02-16 Thread brian.grayson at sifive dot com via Gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99068 --- Comment #7 from Brian Grayson --- A single lhau instruction is better than two instructions (lha + addi) for many reasons. Are there reasons that you feel a two-instruction sequence of lha+addi is *superior* to just an lhau? On all PowerPC i

[Bug tree-optimization/99068] Missed PowerPC lhau optimization

2021-02-16 Thread segher at gcc dot gnu.org via Gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99068 --- Comment #6 from Segher Boessenkool --- (In reply to Brian Grayson from comment #4) > (In reply to Segher Boessenkool from comment #3) > > Then you get > > > > addi 9,9,-2 > > lhau 10,2(9) > > addi 9,9,2 > > > > which is worse than just > >

[Bug tree-optimization/99068] Missed PowerPC lhau optimization

2021-02-16 Thread segher at gcc dot gnu.org via Gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99068 Segher Boessenkool changed: What|Removed |Added Status|UNCONFIRMED |RESOLVED Resolution|---

[Bug tree-optimization/99068] Missed PowerPC lhau optimization

2021-02-12 Thread brian.grayson at sifive dot com via Gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99068 Brian Grayson changed: What|Removed |Added Resolution|INVALID |--- Status|RESOLVED

[Bug tree-optimization/99068] Missed PowerPC lhau optimization

2021-02-12 Thread segher at gcc dot gnu.org via Gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99068 Segher Boessenkool changed: What|Removed |Added Status|UNCONFIRMED |RESOLVED Resolution|---

[Bug tree-optimization/99068] Missed PowerPC lhau optimization

2021-02-12 Thread brian.grayson at sifive dot com via Gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99068 Brian Grayson changed: What|Removed |Added Resolution|INVALID |--- Status|RESOLVED

[Bug tree-optimization/99068] Missed PowerPC lhau optimization

2021-02-12 Thread segher at gcc dot gnu.org via Gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99068 Segher Boessenkool changed: What|Removed |Added Status|UNCONFIRMED |RESOLVED Resolution|---

[Bug tree-optimization/99068] Missed PowerPC lhau optimization

2021-02-10 Thread pinskia at gcc dot gnu.org via Gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99068 Andrew Pinski changed: What|Removed |Added Severity|normal |enhancement Component|target