[llvm] r288840 - GlobalISel: fall back gracefully when we hit unhandled legalizer default.

[Justin Bogner via llvm-commits]

Tim Northover via llvm-commits <llvm-commits at lists.llvm.org> writes:
> Author: tnorthover
> Date: Tue Dec  6 13:02:15 2016
> New Revision: 288840
>
> URL: http://llvm.org/viewvc/llvm-project?rev=288840&view=rev
> Log:
> GlobalISel: fall back gracefully when we hit unhandled legalizer default.
>
> Modified:
>     llvm/trunk/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
>     llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-fallback.ll
>
> Modified: llvm/trunk/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/GlobalISel/LegalizerInfo.cpp?rev=288840&r1=288839&r2=288840&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/GlobalISel/LegalizerInfo.cpp (original)
> +++ llvm/trunk/lib/CodeGen/GlobalISel/LegalizerInfo.cpp Tue Dec  6 13:02:15 2016
> @@ -93,7 +93,9 @@ LegalizerInfo::getAction(const InstrAspe
>      if (DefaultAction != DefaultActions.end() && DefaultAction->second == Legal)
>        return std::make_pair(Legal, Ty);
>  
> -    assert(DefaultAction->second == NarrowScalar && "unexpected default");
> +    if (DefaultAction == DefaultActions.end() ||
> +        DefaultAction->second != NarrowScalar)
> +      return std::make_pair(Unsupported, LLT());

This should still assert/abort when TPC->isGlobalISelAbortEnabled(), or
at least only set FailedISel when it isn't. As is we end up falling into
ResetMachineFunctionPass and failing generically when we hit this, as we
did in llvm.org/pr31669.

>      return findLegalAction(Aspect, NarrowScalar);
>    }
>  
>
> Modified: llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-fallback.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-fallback.ll?rev=288840&r1=288839&r2=288840&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-fallback.ll (original)
> +++ llvm/trunk/test/CodeGen/AArch64/GlobalISel/arm64-fallback.ll Tue Dec  6 13:02:15 2016
> @@ -74,3 +74,11 @@ define void @odd_type(i42* %addr) {
>  define void @sequence_mapping([2 x i64] %in) {
>    ret void
>  }
> +
> +  ; Legalizer was asserting when it enountered an unexpected default action.
> +; FALLBACK-WITH-REPORT-ERR: warning: Instruction selection used fallback path for legal_default
> +; FALLBACK-WITH-REPORT-LABEL: legal_default:
> +define void @legal_default(i64 %in) {
> +  insertvalue [2 x i64] undef, i64 %in, 0
> +  ret void
> +}
>
>
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