llvm dev - Jun 2016 - What kind of testcases should be required to test IPRA?

Hello Mehdi Amini,

Sorry for slow progress this week but it was due to interesting mistake of
mine. I had build llvm with ipra enable by default and that build files
were on my path ! Due to that next time I tried to build llvm it was
terribly slow  (almost 1 hour for 10% build ). I spend to much time on
fixing this by playing around with environment variables, cmake options etc.
But I think this is a serious concern, we need to think verify this time
complexity other wise building a large software with IPRA enable would be
very time consuming.

I studied tets case suggest by you on phabricator, for RegUsageInfo passes
I am thinking to print clobbered registers and verify that with FileCheck
as expected clobbered register for a particular test-case. Is this approach
fine?

I did not find function call to CostModelAnalysis::print() , Is opt
-analyze making that call ?
I am not able to find similar option in llc. I can't use info printed with
dbgs() function as release build do not add -debug-only option to llc
executable.

For the testcase sent by you earlier I have modified it as following :
;;;;; ip-regallco-simple.ll
; RUN: llc < %s | FileCheck %s -check-prefix=NOIPRA
; RUN: llc < %s -enable-ipra | FileCheck %s
; NOIPRA: foo:
; NOIPRA: pushq %r10
; NOIPRA: pushq %r9
; NOIPRA: pushq %r8
; NOIPRA: callq bar1
; CHECK: foo:
; CHECK-NOT: pushq %r10
; CHECK-NOT: pushq %r9
; CHECK-NOT: pushq %r8
; CHECK: callq bar1
target triple = "x86_64-unknown-unknown"
define void @bar1() {
ret void
}
define preserve_allcc void @foo()#0 {
call void @bar1()
call void @bar2()
ret void
}
define void @bar2() {
ret void
}
attributes #0 = {nounwind}

Is this correct approach to verify spills?

Sincerely,
Vivek
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> On Jun 4, 2016, at 7:56 PM, vivek pandya <vivekvpandya at gmail.com>
wrote:
> 
> Hello Mehdi Amini,
> 
> Sorry for slow progress this week but it was due to interesting mistake of
mine. I had build llvm with ipra enable by default and that build files were on
my path ! Due to that next time I tried to build llvm it was terribly slow 
(almost 1 hour for 10% build ). I spend to much time on fixing this by playing
around with environment variables, cmake options etc.
> But I think this is a serious concern, we need to think verify this time
complexity other wise building a large software with IPRA enable would be very
time consuming.
Did you build your own clang in release mode or debug? That makes a very
important difference...
> 
> I studied tets case suggest by you on phabricator, for RegUsageInfo passes
I am thinking to print clobbered registers and verify that with FileCheck as
expected clobbered register for a particular test-case. Is this approach fine?
> 
> I did not find function call to CostModelAnalysis::print() , Is opt
-analyze making that call ?
Yes.
(In general, if you find yourself in a situation where you can find the caller
for a function, run in a debugger and set a breakpoint)
> I am not able to find similar option in llc.
That's an issue. Looks it may not be feasible to test the analysis in llc
with the current infrastructure.
> I can't use info printed with dbgs() function as release build do not
add -debug-only option to llc executable.
> 
> For the testcase sent by you earlier I have modified it as following :
> ;;;;; ip-regallco-simple.ll
> ; RUN: llc < %s | FileCheck %s -check-prefix=NOIPRA
> ; RUN: llc < %s -enable-ipra | FileCheck %s
> ; NOIPRA: foo:
should be NOIPRA-LABEL:
> ; NOIPRA: pushq	%r10
> ; NOIPRA: pushq	%r9
> ; NOIPRA: pushq	%r8 
> ; NOIPRA: calls bar1
If this is an exact sequence you want to match, you may use NOIPRA-NEXT:
> ; CHECK: foo:
> ; CHECK-NOT: pushq %r10
> ; CHECK-NOT: pushq %r9
> ; CHECK-NOT: pushq %r8
You can just write "CHECK-NOT: push"
> ; CHECK: callq bar1
> target triple = "x86_64-unknown-unknown"
> define void @bar1() {
> 	ret void
> }
> define preserve_allcc void @foo()#0 {
> 	call void @bar1()
> 	call void @bar2()
> 	ret void
> }
> define void @bar2() {
> 	ret void
> }
> attributes #0 = {nounwind}
> 
> Is this correct approach to verify spills?
Yes.


-- 
Mehdi

On Sun, Jun 5, 2016 at 8:56 AM, Mehdi Amini <mehdi.amini at apple.com>
wrote:
>
> > On Jun 4, 2016, at 7:56 PM, vivek pandya <vivekvpandya at
gmail.com> wrote:
> >
> > Hello Mehdi Amini,
> >
> > Sorry for slow progress this week but it was due to interesting
mistake
> of mine. I had build llvm with ipra enable by default and that build files
> were on my path ! Due to that next time I tried to build llvm it was
> terribly slow  (almost 1 hour for 10% build ). I spend to much time on
> fixing this by playing around with environment variables, cmake options
etc.
> > But I think this is a serious concern, we need to think verify this
time
> complexity other wise building a large software with IPRA enable would be
> very time consuming.
>
> Did you build your own clang in release mode or debug? That makes a very
> important difference...
>
oh yes nice point, what I did is Debug mode with IPRA 😬 that is insane.
>
> >
> > I studied tets case suggest by you on phabricator, for RegUsageInfo
> passes I am thinking to print clobbered registers and verify that with
> FileCheck as expected clobbered register for a particular test-case. Is
> this approach fine?
> >
> > I did not find function call to CostModelAnalysis::print() , Is opt
> -analyze making that call ?
>
> Yes.
> (In general, if you find yourself in a situation where you can find the
> caller for a function, run in a debugger and set a breakpoint)
>
Ok
>
> > I am not able to find similar option in llc.
>
> That's an issue. Looks it may not be feasible to test the analysis in
llc
> with the current infrastructure.
>
> I got the trick, actaully I am trying to do the same thing but let me
figure out why it does not work?
./print-machineinstrs.ll:; RUN: llc < %s -O3 -debug-pass=Structure
-print-machineinstrs=branch-folder -o /dev/null 2>&1 | FileCheck %s
./print-machineinstrs.ll:; RUN: llc < %s -O3 -debug-pass=Structure
-print-machineinstrs -o /dev/null 2>&1 | FileCheck %s
./print-machineinstrs.ll:; RUN: llc < %s -O3 -debug-pass=Structure
-print-machineinstrs= -o /dev/null 2>&1 | FileCheck %s
> > I can't use info printed with dbgs() function as release build do
not
> add -debug-only option to llc executable.
> >
> > For the testcase sent by you earlier I have modified it as following :
> > ;;;;; ip-regallco-simple.ll
> > ; RUN: llc < %s | FileCheck %s -check-prefix=NOIPRA
> > ; RUN: llc < %s -enable-ipra | FileCheck %s
> > ; NOIPRA: foo:
>
> should be NOIPRA-LABEL:
>
> > ; NOIPRA: pushq       %r10
> > ; NOIPRA: pushq       %r9
> > ; NOIPRA: pushq       %r8
> > ; NOIPRA: calls bar1
>
> If this is an exact sequence you want to match, you may use NOIPRA-NEXT
> > ; CHECK: foo:
> > ; CHECK-NOT: pushq %r10
> > ; CHECK-NOT: pushq %r9
> > ; CHECK-NOT: pushq %r8
>
> You can just write "CHECK-NOT: push"
>
> > ; CHECK: callq bar1
> > target triple = "x86_64-unknown-unknown"
> > define void @bar1() {
> >       ret void
> > }
> > define preserve_allcc void @foo()#0 {
> >       call void @bar1()
> >       call void @bar2()
> >       ret void
> > }
> > define void @bar2() {
> >       ret void
> > }
> > attributes #0 = {nounwind}
> >
> > Is this correct approach to verify spills?
>
> Yes.
>
>
> --
> Mehdi
>
>
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