[llvm] [AMDGPU][ISel] Set trunc store action to expand for v4f32->v4bf16 (PR #90427)

[Changpeng Fang via llvm-commits]

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@@ -316,6 +316,7 @@ AMDGPUTargetLowering::AMDGPUTargetLowering(const TargetMachine &TM,
   setTruncStoreAction(MVT::v2f32, MVT::v2f16, Expand);
   setTruncStoreAction(MVT::v3f32, MVT::v3f16, Expand);
   setTruncStoreAction(MVT::v4f32, MVT::v4f16, Expand);
+  setTruncStoreAction(MVT::v4f32, MVT::v4bf16, Expand);
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changpeng wrote:

Can you also look at other vector size like v2bf16, v8bf16, etc for TruncStoreAction? Thanks.

https://github.com/llvm/llvm-project/pull/90427