Displaying 20 results from an estimated 100 matches similar to: "[LLVMdev] Req-sequence, partial defs"
2012 Oct 24
3
[LLVMdev] RegisterCoalescing Pass seems to ignore part of CFG.
Hi,
I don't know if my llvm ir code is faulty, or if I spot a bug in the RegisterCoalescing Pass, so I'm posting my issue on the ML. Shader and print-before-all dump are given below.
The interessing part is the vreg6/vreg48 reduction : before RegCoalescing, the machine code is :
// BEFORE LOOP
... Some COPYs....
400B%vreg47<def> = COPY %vreg2<kill>; R600_Reg32:%vreg47,%vreg2
2012 Oct 25
0
[LLVMdev] RegisterCoalescing Pass seems to ignore part of CFG.
Hi Vincent,
On 24/10/2012 23:26, Vincent Lejeune wrote:
> Hi,
>
> I don't know if my llvm ir code is faulty, or if I spot a bug in the RegisterCoalescing Pass, so I'm posting my issue on the ML. Shader and print-before-all dump are given below.
>
> The interessing part is the vreg6/vreg48 reduction : before RegCoalescing, the machine code is :
>
> // BEFORE LOOP
>
2012 Oct 26
1
[LLVMdev] RegisterCoalescing Pass seems to ignore part of CFG.
Vincent,
File a bug report so you can get a fix for it.
Ivan
On 25/10/2012 23:01, Vincent Lejeune wrote:
> Thank for your help. You're right, merging vreg32 and vreg48 is perfectly fine, sorry I missed that.
> I "brute force" debuged by adding MachineFunction dump after each join, I think I found the issue : it's when vreg32 and vreg10 are merged.
> vreg10 only
2012 Oct 25
0
[LLVMdev] RegisterCoalescing Pass seems to ignore part of CFG.
Thank for your help. You're right, merging vreg32 and vreg48 is perfectly fine, sorry I missed that.
I "brute force" debuged by adding MachineFunction dump after each join, I think I found the issue : it's when vreg32 and vreg10 are merged.
vreg10 only appears in BB#3, and the join only occurs in BB#3 apparently even if vreg32 lives in the 4 machine blocks
After joining, there
2017 Oct 13
2
Machine Scheduler on Power PC: Latency Limit and Register Pressure
Hi,
I've been looking at the Machine Scheduler on Power PC. I am looking only
at the pre-RA machine scheduler and I am running it in the default
bi-directional mode (so, both top down and bottom up queues are
considered). I've come across an example where the scheduler picks a poor
ordering for the instructions which results in very high register pressure
which results in spills.
2016 Aug 23
2
Help in understanding physreg LiveVariables
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<div dir="ltr" >Hi all,</div>
<div dir="ltr" > </div>
<div
2012 Oct 25
2
[LLVMdev] RegisterCoalescing Pass seems to ignore part of CFG.
>
> PHIElim and TwoAddress passes leave SSA form.
> May be a missed something in your code but %vreg48 seems to be there
> after PHI elimination. PHIElim tags those kind of registers as being
> PHIJoin regs, updating LiveVariables pass, so the regcoalescer is aware
> of them (some SSA info is still alive but the reg coalescer will
> invalidate that information after
2012 Aug 06
4
[LLVMdev] Register Coalescer does not preserve TargetFlag
Hi,
R600 hardware (Radeon gfx card) does neither have a NEG nor an ABS instruction ; however any sources operand can be negated/abs'd by setting a bit for every source operand in the final bytecode (but not DST).
A good way of modeling this behavior in LLVM is by using TargetFlag on operand.
Currently the R600 LLVM backend in Mesa lower NEG and ABS DAG instruction to a MOV + TargetFlag using
2012 Oct 25
3
[LLVMdev] RegisterCoalescing Pass seems to ignore part of CFG.
Hi Vincent,
On 25/10/2012 18:14, Vincent Lejeune wrote:
> When examining the debug output of regalloc, it seems that joining 32bits reg also joins 128 parent reg.
>
> If I look at the :
> %vreg34<def> = COPY %vreg6:sel_y; R600_Reg32:%vreg34 R600_Reg128:%vreg6
>
> instructions ; it gets joined to :
> 928B%vreg34<def> = COPY %vreg48:sel_y;
>
> when vreg6 and
2014 Aug 19
2
[LLVMdev] Help with definition of subregisters; spill, rematerialization and implicit uses
Hi Quentin,
On 08/15/14 19:01, Quentin Colombet wrote:
[...]
>> The question is: How should true subregister definitions be
>> expressed so that they do not interfere with each other? See the
>> detailed problem description below.
>
> We do have a limitation in our current liveness tracking for
> sub-register. Therefore, I am not sure that is possible.
>
>
2012 Oct 25
0
[LLVMdev] RegisterCoalescing Pass seems to ignore part of CFG.
When examining the debug output of regalloc, it seems that joining 32bits reg also joins 128 parent reg.
If I look at the :
%vreg34<def> = COPY %vreg6:sel_y; R600_Reg32:%vreg34 R600_Reg128:%vreg6
instructions ; it gets joined to :
928B%vreg34<def> = COPY %vreg48:sel_y;
when vreg6 and vreg48 are joined. It's right.
But joining the following copy
2012 Jul 09
0
[LLVMdev] Possible issue with EXPANDING POST-RA PSEUDO INSTRS
On Jul 8, 2012, at 3:42 PM, Sergei Larin <slarin at codeaurora.org> wrote:
> ********** EXPANDING POST-RA PSEUDO INSTRS **********
> ********** Function: main
> real copy: %R15<def> = COPY %R4, %D2<imp-use,kill>, %D7<imp-use,kill>,
> %D7<imp-def>
> replaced by: %R15<def> = TFR %R4, %D7<imp-def>
>
> The R4 is a subreg of D2 double
2012 Jul 08
2
[LLVMdev] Possible issue with EXPANDING POST-RA PSEUDO INSTRS
Hello everyone,
I am running into an obscure issue with ExpandPostRA. Does anyone
recognizes the following:
The pass replaces a real copy with a "transfer" instruction:
********** EXPANDING POST-RA PSEUDO INSTRS **********
********** Function: main
real copy: %R15<def> = COPY %R4, %D2<imp-use,kill>, %D7<imp-use,kill>,
%D7<imp-def>
replaced by:
2017 Oct 13
3
Machine Scheduler on Power PC: Latency Limit and Register Pressure
> On Oct 13, 2017, at 1:46 PM, Matthias Braun <matze at braunis.de> wrote:
>
> Yes, I've run into the problem myself that the Pending queue isn't even checked with the tryCandidate() logic and so takes priority over all other scheduling decisions.
>
> I personally would be open to changes in this area. To start the brainstorming I could imagine that we move nodes
2012 Jul 04
2
[LLVMdev] Assertion in PHIElimination.cpp
Hi everyone
I'm hitting an assertion in PHIElimination.cpp:375.
"Terminator instructions cannot use virtual registers unless"
"they are the first terminator in a block!"
I was looking at the code around that location a bit and have not found
a reason why this assertion has to hold, except for a comment:
// In our final twist, we have to decide which instruction
2016 Aug 02
2
Instruction selection problems due to SelectionDAGBuilder
Hello.
I'm having problems at instruction selection with my back end with the following
basic-block due to a vector add with immediate constant vector (obtained by vectorizing a
simple C program doing vector sum map):
vector.ph: ; preds = %vector.memcheck50
%.splatinsert = insertelement <8 x i64> undef, i64 %i.07.unr, i32 0
2016 Aug 23
2
Help in understanding physreg LiveVariables
<div class="socmaildefaultfont" dir="ltr" style="font-family:Arial;font-size:10.5pt" ><div dir="ltr" style="font-family:Arial;font-size:10.5pt" ><div dir="ltr" >Matthias,</div>
<div dir="ltr" > </div>
<div dir="ltr" >Thanks for the response.</div>
<div
2005 Sep 23
1
panel.linejoin groups
Dear R community,
I am still new to R, but I am attempting to use it for (hopefully) all
my plotting needs. I have been using lattice and Hmisc for most plots
so far successfully, but I need help creating a plot I desire for some
new data I have.
This data frame consists of the same type of measurement (Eh) for 27
different locations. I have 8000+ measurements for each location, and
my
2013 Jun 24
1
[LLVMdev] DebugInfo: Missing non-trivially-copyable parameters in SelectionDAG
This is a bit premature to be considered a code review, but given how
unfamiliar I am with SelectionDAG (& that I'm seeing somewhat more
'interesting' results compared to my change to FastISel) I wanted to
get a bit of feedback to see if I was on the right track or had missed
any obvious cases.
I've attached my patch in progress (including a modification to the
existing test
2011 Mar 22
5
FPGA encode stages flow diagram
Good day!
I create diagram of encoder process. Using it i create implementation of
encoder in FPGA (Xilinx/Altera). Please critique it. Is there missing
stages?
Here is blog http://developer-fpga.blogspot.com/
Here is picture of encoding stage 1
https://lh4.googleusercontent.com/-NV8o9DG3jvE/TYjYXr-dYGI/AAAAAAAAAos/U06O-YvhSI0/s1600/stage1.jpg
Here is picture of encoding stage 2