[PATCH] SelectionDAG: Make sure stores are always added to the LegalizedNodes list

[Owen Anderson]

LGTM.

--Owen

On Aug 19, 2013, at 8:28 AM, Tom Stellard <tom at stellard.net> wrote:

> From: Tom Stellard <thomas.stellard at amd.com>
> 
> When truncated vector stores were being custom lowered in
> VectorLegalizer::LegalizeOp(), the old (illegal) and new (legal) node pair
> was not being added to LegalizedNodes list.  Instead of the legalized
> result being passed to VectorLegalizer::TranslateLegalizeResult(),
> the result was being passed back into VectorLegalizer::LegalizeOp(),
> which ended up adding a (new, new) pair to the list instead.
> 
> This was causing an assertion failure when a custom lowered truncated
> vector store was the last instruction a basic block and the VectorLegalizer
> was unable to find it in the LegalizedNodes list when updating the
> DAG root.
> ---
> lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp       |  2 +-
> .../R600/trunc-vector-store-assertion-failure.ll     | 20 ++++++++++++++++++++
> 2 files changed, 21 insertions(+), 1 deletion(-)
> create mode 100644 test/CodeGen/R600/trunc-vector-store-assertion-failure.ll
> 
> diff --git a/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp b/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
> index 56834d1..e1809de 100644
> --- a/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
> +++ b/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
> @@ -171,7 +171,7 @@ SDValue VectorLegalizer::LegalizeOp(SDValue Op) {
>         return TranslateLegalizeResults(Op, Result);
>       case TargetLowering::Custom:
>         Changed = true;
> -        return LegalizeOp(TLI.LowerOperation(Result, DAG));
> +        return TranslateLegalizeResults(Op, TLI.LowerOperation(Result, DAG));
>       case TargetLowering::Expand:
>         Changed = true;
>         return LegalizeOp(ExpandStore(Op));
> diff --git a/test/CodeGen/R600/trunc-vector-store-assertion-failure.ll b/test/CodeGen/R600/trunc-vector-store-assertion-failure.ll
> new file mode 100644
> index 0000000..ec959c2
> --- /dev/null
> +++ b/test/CodeGen/R600/trunc-vector-store-assertion-failure.ll
> @@ -0,0 +1,20 @@
> +; RUN: llc < %s -march=r600 -mcpu=redwood | FileCheck %s
> +
> +; This tests for a bug in the SelectionDAG where custom lowered truncated
> +; vector stores at the end of a basic block were not being added to the
> +; LegalizedNodes list, which triggered an assertion failure.
> +
> +; CHECK-LABEL: @test
> +; CHECK: MEM_RAT_CACHELESS STORE_RAW
> +define void @test(<4 x i8> addrspace(1)* %out, i32 %cond, <4 x i8> %in) {
> +entry:
> +  %0 = icmp eq i32 %cond, 0
> +  br i1 %0, label %if, label %done
> +
> +if:
> +  store <4 x i8> %in, <4 x i8> addrspace(1)* %out
> +  br label %done
> +
> +done:
> +  ret void
> +}
> -- 
> 1.7.11.4
>