[llvm-commits] [llvm] r126190 - in /llvm/trunk: lib/CodeGen/VirtRegRewriter.cpp test/CodeGen/X86/2011-02-21-VirtRegRewriter-KillSubReg.ll

[Evan Cheng]

On Feb 21, 2011, at 11:37 PM, Andrew Trick wrote:

> On Feb 21, 2011, at 10:59 PM, Evan Cheng wrote:
>> 
>> On Feb 21, 2011, at 10:52 PM, Andrew Trick wrote:
>> 
>>> Author: atrick
>>> Date: Tue Feb 22 00:52:56 2011
>>> New Revision: 126190
>>> 
>>> URL: http://llvm.org/viewvc/llvm-project?rev=126190&view=rev
>>> Log:
>>> VirtRegRewriter assertion fix.
>>> Apparently it's ok for multiple operands to "kill" the same register.
>> 
>> It is?
>> 
>> Evan
> 
> Prior to the standard spiller, we have:
>   MOV8mr %vreg34<kill>, 1, %noreg, 3, %noreg, %vreg34:sub_8bit<kill>; mem:ST1[%arrayidx833] GR32_ABCD:%vreg34
> 
> Before rewriting we have:
>   %EAX<def> = MOV32rm <fi#0>, 1, %noreg, 0, %noreg; mem:LD4[FixedStack0]
>   MOV8mr %EAX<kill>, 1, %noreg, 3, %noreg, %AL<kill>; mem:ST1[%arrayidx833]

The *right* representation is for EAX being the only kill. But I agree it's hard to eliminate the extra kill.

Evan

> 
> After rewriting:
>   %EAX<def> = MOV32rm <fi#0>, 1, %noreg, 0, %noreg; mem:LD4[FixedStack0]
>   MOV8mr %EAX, 1, %noreg, 3, %noreg, %AL<kill>; mem:ST1[%arrayidx833]
> 
> It seems valid enough to me for a combination of passes that will hopefully soon be deprecated. I'm honestly not sure yet what the ideal rules should be for subreg kill flags.
> 
> -Andy
> 
>> 
>>> Fixes PR9237.
>>> 
>>> Added:
>>>   llvm/trunk/test/CodeGen/X86/2011-02-21-VirtRegRewriter-KillSubReg.ll
>>> Modified:
>>>   llvm/trunk/lib/CodeGen/VirtRegRewriter.cpp
>>> 
>>> Modified: llvm/trunk/lib/CodeGen/VirtRegRewriter.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/VirtRegRewriter.cpp?rev=126190&r1=126189&r2=126190&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/lib/CodeGen/VirtRegRewriter.cpp (original)
>>> +++ llvm/trunk/lib/CodeGen/VirtRegRewriter.cpp Tue Feb 22 00:52:56 2011
>>> @@ -478,7 +478,8 @@
>>>  if (!RegKills[KReg])
>>>    return;
>>> 
>>> -  assert(KillOps[KReg] == KillOp && "invalid superreg kill flags");
>>> +  assert(KillOps[KReg]->getParent() == KillOp->getParent() &&
>>> +         "invalid superreg kill flags");
>>>  KillOps[KReg] = NULL;
>>>  RegKills.reset(KReg);
>>> 
>>> @@ -487,7 +488,8 @@
>>>  for (const unsigned *SR = TRI->getSubRegisters(KReg); *SR; ++SR) {
>>>    DEBUG(dbgs() << "  Resurrect subreg " << TRI->getName(*SR) << "\n");
>>> 
>>> -    assert(KillOps[*SR] == KillOp && "invalid subreg kill flags");
>>> +    assert(KillOps[*SR]->getParent() == KillOp->getParent() &&
>>> +           "invalid subreg kill flags");
>>>    KillOps[*SR] = NULL;
>>>    RegKills.reset(*SR);
>>>  }
>>> 
>>> Added: llvm/trunk/test/CodeGen/X86/2011-02-21-VirtRegRewriter-KillSubReg.ll
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/2011-02-21-VirtRegRewriter-KillSubReg.ll?rev=126190&view=auto
>>> ==============================================================================
>>> --- llvm/trunk/test/CodeGen/X86/2011-02-21-VirtRegRewriter-KillSubReg.ll (added)
>>> +++ llvm/trunk/test/CodeGen/X86/2011-02-21-VirtRegRewriter-KillSubReg.ll Tue Feb 22 00:52:56 2011
>>> @@ -0,0 +1,50 @@
>>> +; RUN: llc < %s -O2 -march=x86 -mtriple=i386-pc-linux-gnu -relocation-model=pic | FileCheck %s
>>> +; PR9237: Assertion in VirtRegRewriter.cpp, ResurrectConfirmedKill
>>> +;         `KillOps[*SR] == KillOp && "invalid subreg kill flags"'
>>> +
>>> +%t = type { i32 }
>>> +
>>> +define i32 @foo(%t* %s) nounwind {
>>> +entry:
>>> +  br label %if.then735
>>> +
>>> +if.then735:
>>> +  %call747 = call i32 undef(%t* %s, i8* null, i8* undef, i32 128, i8* undef, i32 516) nounwind
>>> +  br i1 undef, label %if.then751, label %if.then758
>>> +
>>> +if.then751:
>>> +  unreachable
>>> +
>>> +if.then758:
>>> +  %add761 = add i32 %call747, 4
>>> +  %add763 = add i32 %add761, %call747
>>> +  %add.ptr768 = getelementptr inbounds [516 x i8]* null, i32 0, i32 %add761
>>> +  br i1 undef, label %cond.false783, label %cond.true771
>>> +
>>> +cond.true771:
>>> +  %call782 = call i8* @__memmove_chk(i8* %add.ptr768, i8* undef, i32 %call747, i32 undef)
>>> +  br label %cond.end791
>>> +
>>> +; CHECK: calll __memmove_chk
>>> +cond.false783:
>>> +  %call.i1035 = call i8* @__memmove_chk(i8* %add.ptr768, i8* undef, i32 %call747, i32 undef) nounwind
>>> +  br label %cond.end791
>>> +
>>> +cond.end791:
>>> +  %conv801 = trunc i32 %call747 to i8
>>> +  %add.ptr822.sum = add i32 %call747, 3
>>> +  %arrayidx833 = getelementptr inbounds [516 x i8]* null, i32 0, i32 %add.ptr822.sum
>>> +  store i8 %conv801, i8* %arrayidx833, align 1
>>> +  %cmp841 = icmp eq i8* undef, null
>>> +  br i1 %cmp841, label %if.end849, label %if.then843
>>> +
>>> +if.then843:
>>> +  unreachable
>>> +
>>> +if.end849:
>>> +  %call921 = call i32 undef(%t* %s, i8* undef, i8* undef, i32 %add763) nounwind
>>> +  unreachable
>>> +
>>> +}
>>> +
>>> +declare i8* @__memmove_chk(i8*, i8*, i32, i32) nounwind
>>> 
>>> 
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>> 
> 

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