Displaying 9 results from an estimated 9 matches for "reg1176".
2009 Jan 30
2
[LLVMdev] undefs in phis
...see. But coalescing seems to break. I don't know if it's because
of the eliminated IMPLICIT_DEF, though. Here's what happens. Let's look at
this code, annotated with live range indices:
bb134:
2696 %reg1645<def> = FsMOVAPSrr %reg1458<kill> ; srcLine 0
bb74:
2700 %reg1176<def> = FsMOVAPSrr %reg1645<kill> ; srcLine 0
2704 %reg1177<def> = FsMOVAPSrr %reg1646<kill> ; srcLine 0 *** u before d
2708 %reg1178<def> = FsMOVAPSrr %reg1647<kill> ; srcLine 0 *** u before d
2712 TEST64rr %reg1173, %reg1173, %EFLAGS<imp-def> ; srcLi...
2009 Jan 30
2
[LLVMdev] undefs in phis
On Jan 30, 2009, at 1:52 PM, David Greene wrote:
> On Friday 30 January 2009 15:10, David Greene wrote:
>
>> This still looks correct. The coalescer then says:
>>
>> 4360 %reg1177<def> = FsMOVAPSrr %reg1176<kill> ; srcLine 0
>> Inspecting %reg1176,0 = [2702,4362:0) 0 at 2702-(4362) and
>> %reg1177,0 =
>> [2700,3712:0)[3768,3878:0)[4362,4372:0) 0 at 4362-(3878):
>> Joined. Result = %reg1177,0 = [2700,4372:0) 0 at 2702-(4362)
>>
>> Eh? How can it coa...
2009 Jan 30
0
[LLVMdev] undefs in phis
On Friday 30 January 2009 15:10, David Greene wrote:
> This still looks correct. The coalescer then says:
>
> 4360 %reg1177<def> = FsMOVAPSrr %reg1176<kill> ; srcLine 0
> Inspecting %reg1176,0 = [2702,4362:0) 0 at 2702-(4362) and %reg1177,0 =
> [2700,3712:0)[3768,3878:0)[4362,4372:0) 0 at 4362-(3878):
> Joined. Result = %reg1177,0 = [2700,4372:0) 0 at 2702-(4362)
>
> Eh? How can it coalesce these two? Doesn't %...
2009 Feb 02
0
[LLVMdev] undefs in phis
...alue. So we don't
> care if a live interval overlaps live ranges defined by an implicit_def.
It's a bug because the coalerscer does illegal coaescing.
Our last episode left us here:
bb134:
2696 %reg1645<def> = FsMOVAPSrr %reg1458<kill> ; srcLine 0
bb74:
2700 %reg1176<def> = FsMOVAPSrr %reg1645<kill> ; srcLine 0
[deleted copy]
2708 %reg1178<def> = FsMOVAPSrr %reg1647<kill> ; srcLine 0 *** u
before d
2712 TEST64rr %reg1173, %reg1173, %EFLAGS<imp-def> ; srcLine 30
2716 JLE mbb<file test.f90, bb90,0x3c37ed...
2009 Jan 30
2
[LLVMdev] undefs in phis
On Thursday 29 January 2009 18:04, Eli Friedman wrote:
> On Thu, Jan 29, 2009 at 2:47 PM, David Greene <dag at cray.com> wrote:
> > After phi elimination we have:
> >
> > bb134:
> > %reg1645 = 1.0
> >
> > bb74:
> > %reg1176 = MOVAPS %reg1645
> > %reg1177 = MOVAPS %reg1646
> > [...]
> >
> > bb108:
> > %reg1645 = <expr>
> > %reg1646 = %reg1176
>
> I find it a little strange that the IMPLICIT_DEF disappears. Besides
> that, it looks okay up to here.
I just verified...
2009 Jan 29
2
[LLVMdev] undefs in phis
...erstand a bit more of what's going on in my phi example.
Coming into DAGtoDAG we have this code:
bb74:
x = phi(1.0:bb134, %r1450:bb108)
y = phi(undef:bb134, x:bb108)
[...]
bb108:
%r1450 = <expr>
After DAGtoDAG we have:
bb134:
%reg1459 = IMPLICIT_DEF
%reg1458 = 1.0
bb74:
%reg1176 = phi(%reg1458:bb134, %reg1253:bb108)
%reg1177 = phi(%reg1459:bb134, %reg1176:bb108)
[...]
bb108:
%reg1253 = <expr>
So far so good, though the IMPLICIT_DEF is worrisome. I'm guessing that's
what causes problems later.
After phi elimination we have:
bb134:
%reg1645 = 1.0
b...
2009 Jan 30
0
[LLVMdev] undefs in phis
...:
> On Thursday 29 January 2009 18:04, Eli Friedman wrote:
>> On Thu, Jan 29, 2009 at 2:47 PM, David Greene <dag at cray.com> wrote:
>>> After phi elimination we have:
>>>
>>> bb134:
>>> %reg1645 = 1.0
>>>
>>> bb74:
>>> %reg1176 = MOVAPS %reg1645
>>> %reg1177 = MOVAPS %reg1646
>>> [...]
>>>
>>> bb108:
>>> %reg1645 = <expr>
>>> %reg1646 = %reg1176
>>
>> I find it a little strange that the IMPLICIT_DEF disappears. Besides
>> that, it looks okay up...
2009 Feb 02
2
[LLVMdev] undefs in phis
...ps live ranges defined by an
>> implicit_def.
>
> It's a bug because the coalerscer does illegal coaescing.
>
> Our last episode left us here:
>
> bb134:
> 2696 %reg1645<def> = FsMOVAPSrr %reg1458<kill> ; srcLine 0
>
> bb74:
> 2700 %reg1176<def> = FsMOVAPSrr %reg1645<kill> ; srcLine 0
> [deleted copy]
> 2708 %reg1178<def> = FsMOVAPSrr %reg1647<kill> ; srcLine
> 0 *** u
> before d
> 2712 TEST64rr %reg1173, %reg1173, %EFLAGS<imp-def> ; srcLine 30
> 2716 JLE mbb...
2009 Jan 30
0
[LLVMdev] undefs in phis
On Thu, Jan 29, 2009 at 2:47 PM, David Greene <dag at cray.com> wrote:
> After phi elimination we have:
>
> bb134:
> %reg1645 = 1.0
>
> bb74:
> %reg1176 = MOVAPS %reg1645
> %reg1177 = MOVAPS %reg1646
> [...]
>
> bb108:
> %reg1645 = <expr>
> %reg1646 = %reg1176
I find it a little strange that the IMPLICIT_DEF disappears. Besides
that, it looks okay up to here.
> Should llvm be able to handle situations like
> this...