https://gcc.gnu.org/bugzilla/show_bug.cgi?id=18154
--- Comment #13 from Segher Boessenkool ---
Trunk now generates isel for power9.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=18154
--- Comment #12 from Segher Boessenkool ---
(Never mind those last "addc" insn, they can just as well be plain
"add", I pasted the wrong ones).
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=18154
--- Comment #11 from Segher Boessenkool ---
The signed version can be done in four insns:
1: subfc r5,r3,r4
subfe r6,r6,r6
and r7,r6,r5
addcr8,r7,r3
(superopt finds 16 versions, all similar).
The unsign
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=18154
--- Comment #10 from David Edelsohn ---
isel is not generally performance win for Power using GCC. It is enabled for
LLVM because LLVM has a simplistic basic block scheduler and isel allows LLVM
to form larger basic blocks to provide the schedul
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=18154
--- Comment #9 from Martin Sebor ---
I noticed while looking at an unrelated bug that when targeting power7 or
power8 Clang makes use of the isel instruction and emits the following:
min:# @min
cmpw
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=18154
David Edelsohn changed:
What|Removed |Added
Status|WAITING |NEW
CC|
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=18154
Martin Sebor changed:
What|Removed |Added
Target|powerpc-*-* |powerpc*-*-*
Status|NEW
--- Additional Comments From pinskia at gcc dot gnu dot org 2005-04-24
14:31 ---
On the mainline, we now produce:
cmpw cr7,r3,r4
blelr- cr7
mr r3,r4
blr
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18154
--- Additional Comments From pinskia at gcc dot gnu dot org 2004-10-27 23:52
---
I should note when I was doing SPEC work, using subfc/subfe did not help SPEC at all
(I tried to change
the source and also rs6000.md).
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18154
--- Additional Comments From geoffk at gcc dot gnu dot org 2004-10-27 23:45
---
I'm not sure that subfc/subfe is going to be cheaper than a compare and a branch, even
if the branch is
mispredicted half the time. Do you have timing results?
--
http://gcc.gnu.org/bugzilla/show_bug.c
--- Additional Comments From dje at gcc dot gnu dot org 2004-10-26 21:25 ---
Also, do not enable when optimizing for size.
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18154
--- Additional Comments From dje at gcc dot gnu dot org 2004-10-26 20:06 ---
XLC chooses the straight-line code sequence versus compare and branch based on
a cost model. This should not be a uniform change in behavior for PowerPC.
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18154
--- Additional Comments From pinskia at gcc dot gnu dot org 2004-10-26 04:25
---
Confirmed.
--
What|Removed |Added
Status|UNCONFIRMED |NEW
E
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