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Disable IsSub subregister assert. pr18663.
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This is a follow-up to the activity in the bug at
http://llvm.org/bugs/show_bug.cgi?id=18663 .  The underlying issue has
to do with how the KILL pseudo-instruction is handled.  I defer to
Hal/Jakob/Uli for additional details and background.

This will disable the (bad?) assert, add an associated fixme comment,
and add a pair of tests.

The code change and the pr18663-2.ll test are copied from the referenced
bug.  That test does not immediately fail in my environment, but I have
added the pr18663.ll test which does.

(Comment from Hal)
to provide everyone else with some context, this assert was not bad when
it was written. At that time, we only generated KILL pseudo instructions
around subregister copies. This logic, unfortunately, had its own problems.
In r199797, the relevant logic in MachineCopyPropagation was replaced to
generate KILLs for other kinds of copies too. This change in semantics broke
this now-problematic assumption in AggressiveAntiDepBreaker. The
AggressiveAntiDepBreaker really needs a proper cleanup to deal with the
change, but removing the assert (which just allows the function to return
false) is a safe conservative behavior, and should do for the time being.






git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214429 91177308-0d34-0410-b5e6-96231b3b80d8
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@willschm
willschm committed Jul 31, 2014
1 parent 72c5355 commit 723bdb5
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Showing 3 changed files with 454 additions and 1 deletion.
4 changes: 3 additions & 1 deletion lib/CodeGen/AggressiveAntiDepBreaker.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -582,7 +582,9 @@ bool AggressiveAntiDepBreaker::FindSuitableFreeRegisters(
unsigned Reg = Regs[i];
if (Reg == SuperReg) continue;
bool IsSub = TRI->isSubRegister(SuperReg, Reg);
assert(IsSub && "Expecting group subregister");
// FIXME: remove this once PR18663 has been properly fixed. For now,
// return a conservative answer:
// assert(IsSub && "Expecting group subregister");
if (!IsSub)
return false;
}
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153 changes: 153 additions & 0 deletions test/CodeGen/PowerPC/pr18663-2.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,153 @@
; RUN: llc < %s -march=ppc64 -mtriple=powerpc64-unknown-linux-gnu
; RUN: llc < %s -march=ppc64le -mtriple=powerpc64le-unknown-linux-gnu

%"class.std::__1::locale::id.1580.4307.4610.8491" = type { %"struct.std::__1::once_flag.1579.4306.4609.8490", i32 }
%"struct.std::__1::once_flag.1579.4306.4609.8490" = type { i64 }
%"class.Foam::IOerror.1581.4308.4611.8505" = type { %"class.Foam::error.1535.4262.4565.8504", %"class.Foam::string.1530.4257.4560.8499", i32, i32 }
%"class.Foam::error.1535.4262.4565.8504" = type { %"class.std::exception.1523.4250.4553.8492", [36 x i8], %"class.Foam::string.1530.4257.4560.8499", %"class.Foam::string.1530.4257.4560.8499", i32, i8, i8, %"class.Foam::OStringStream.1534.4261.4564.8503"* }
%"class.std::exception.1523.4250.4553.8492" = type { i32 (...)** }
%"class.Foam::OStringStream.1534.4261.4564.8503" = type { %"class.Foam::OSstream.1533.4260.4563.8502" }
%"class.Foam::OSstream.1533.4260.4563.8502" = type { [50 x i8], %"class.Foam::fileName.1531.4258.4561.8500", %"class.std::__1::basic_ostream.1532.4259.4562.8501"* }
%"class.Foam::fileName.1531.4258.4561.8500" = type { %"class.Foam::string.1530.4257.4560.8499" }
%"class.std::__1::basic_ostream.1532.4259.4562.8501" = type { i32 (...)**, [148 x i8] }
%"class.Foam::string.1530.4257.4560.8499" = type { %"class.std::__1::basic_string.1529.4256.4559.8498" }
%"class.std::__1::basic_string.1529.4256.4559.8498" = type { %"class.std::__1::__compressed_pair.1528.4255.4558.8497" }
%"class.std::__1::__compressed_pair.1528.4255.4558.8497" = type { %"class.std::__1::__libcpp_compressed_pair_imp.1527.4254.4557.8496" }
%"class.std::__1::__libcpp_compressed_pair_imp.1527.4254.4557.8496" = type { %"struct.std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__rep.1526.4253.4556.8495" }
%"struct.std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__rep.1526.4253.4556.8495" = type { %union.anon.1525.4252.4555.8494 }
%union.anon.1525.4252.4555.8494 = type { %"struct.std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__long.1524.4251.4554.8493" }
%"struct.std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__long.1524.4251.4554.8493" = type { i64, i64, i8* }

@.str3 = external unnamed_addr constant [16 x i8], align 1
@_ZNSt3__15ctypeIcE2idE = external global %"class.std::__1::locale::id.1580.4307.4610.8491"
@_ZN4Foam12FatalIOErrorE = external global %"class.Foam::IOerror.1581.4308.4611.8505"
@.str204 = external unnamed_addr constant [18 x i8], align 1
@.str205 = external unnamed_addr constant [34 x i8], align 1

declare void @_ZN4FoamlsERNS_7OstreamEPKc() #0

declare i32 @__gxx_personality_v0(...)

declare void @_ZNKSt3__18ios_base6getlocEv() #0

declare void @_ZNKSt3__16locale9use_facetERNS0_2idE() #0

; Function Attrs: noreturn
declare void @_ZNKSt3__121__basic_string_commonILb1EE20__throw_length_errorEv() #1 align 2

declare void @_ZN4Foam6string6expandEb() #0

declare void @_ZN4Foam8IFstreamC1ERKNS_8fileNameENS_8IOstream12streamFormatENS4_13versionNumberE() #0

declare void @_ZN4Foam7IOerrorclEPKcS2_iRKNS_8IOstreamE() #0

declare void @_ZN4Foam7IOerror4exitEi() #0

; Function Attrs: inlinehint
declare void @_ZN4Foam8fileName12stripInvalidEv() #2 align 2

define void @_ZN4Foam3CSVINS_6VectorIdEEE4readEv() #0 align 2 {
entry:
invoke void @_ZN4Foam6string6expandEb()
to label %invoke.cont unwind label %lpad

invoke.cont: ; preds = %entry
br i1 undef, label %if.then.i.i.i.i176, label %_ZN4Foam6stringC2ERKS0_.exit.i

if.then.i.i.i.i176: ; preds = %invoke.cont
invoke void @_ZNKSt3__121__basic_string_commonILb1EE20__throw_length_errorEv()
to label %.noexc unwind label %lpad

.noexc: ; preds = %if.then.i.i.i.i176
unreachable

_ZN4Foam6stringC2ERKS0_.exit.i: ; preds = %invoke.cont
invoke void @_ZN4Foam8fileName12stripInvalidEv()
to label %invoke.cont2 unwind label %lpad.i

lpad.i: ; preds = %_ZN4Foam6stringC2ERKS0_.exit.i
%0 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
cleanup
br label %ehcleanup142

invoke.cont2: ; preds = %_ZN4Foam6stringC2ERKS0_.exit.i
invoke void @_ZN4Foam8IFstreamC1ERKNS_8fileNameENS_8IOstream12streamFormatENS4_13versionNumberE()
to label %invoke.cont4 unwind label %lpad3

invoke.cont4: ; preds = %invoke.cont2
br i1 undef, label %for.body, label %if.then

if.then: ; preds = %invoke.cont4
invoke void @_ZN4Foam7IOerrorclEPKcS2_iRKNS_8IOstreamE()
to label %invoke.cont8 unwind label %lpad5

invoke.cont8: ; preds = %if.then
invoke void @_ZN4FoamlsERNS_7OstreamEPKc()
to label %memptr.end.i unwind label %lpad5

memptr.end.i: ; preds = %invoke.cont8
invoke void @_ZN4Foam7IOerror4exitEi()
to label %if.end unwind label %lpad5

lpad: ; preds = %if.then.i.i.i.i176, %entry
%1 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
cleanup
br label %ehcleanup142

lpad3: ; preds = %invoke.cont2
%2 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
cleanup
br label %ehcleanup142

lpad5: ; preds = %memptr.end.i, %invoke.cont8, %if.then
%3 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
cleanup
br label %ehcleanup142

if.end: ; preds = %memptr.end.i
br i1 undef, label %for.body, label %vector.body

for.body: ; preds = %if.end, %invoke.cont4
invoke void @_ZNKSt3__18ios_base6getlocEv()
to label %.noexc205 unwind label %lpad19

.noexc205: ; preds = %for.body
invoke void @_ZNKSt3__16locale9use_facetERNS0_2idE()
to label %invoke.cont.i.i.i unwind label %lpad.i.i.i

invoke.cont.i.i.i: ; preds = %.noexc205
unreachable

lpad.i.i.i: ; preds = %.noexc205
%4 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
cleanup
br label %ehcleanup142

lpad19: ; preds = %for.body
%5 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
cleanup
br label %ehcleanup142

vector.body: ; preds = %vector.body, %if.end
%vec.phi = phi <8 x i32> [ %10, %vector.body ], [ undef, %if.end ]
%vec.phi1302 = phi <8 x i32> [ %11, %vector.body ], [ undef, %if.end ]
%vec.phi1303 = phi <8 x i32> [ %12, %vector.body ], [ undef, %if.end ]
%vec.phi1304 = phi <8 x i32> [ %13, %vector.body ], [ undef, %if.end ]
%6 = icmp sgt <8 x i32> undef, %vec.phi
%7 = icmp sgt <8 x i32> undef, %vec.phi1302
%8 = icmp sgt <8 x i32> undef, %vec.phi1303
%9 = icmp sgt <8 x i32> undef, %vec.phi1304
%10 = select <8 x i1> %6, <8 x i32> undef, <8 x i32> %vec.phi
%11 = select <8 x i1> %7, <8 x i32> undef, <8 x i32> %vec.phi1302
%12 = select <8 x i1> %8, <8 x i32> undef, <8 x i32> %vec.phi1303
%13 = select <8 x i1> %9, <8 x i32> undef, <8 x i32> %vec.phi1304
br label %vector.body

ehcleanup142: ; preds = %lpad19, %lpad.i.i.i, %lpad5, %lpad3, %lpad, %lpad.i
resume { i8*, i32 } undef
}

attributes #0 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { noreturn "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #2 = { inlinehint "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }

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