[llvm] [SLP][AMDGPU] Vectorize operands of non-trivially-vectorizable intrinsic calls (PR #189784)

[Alexey Bataev via llvm-commits]

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@@ -29477,6 +29507,28 @@ bool SLPVectorizerPass::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
       PostProcessCmps.insert(cast<CmpInst>(&*It));
   }
 
+  // Collect operands of non-trivially vectorizable intrinsic calls (e.g.,
+  // llvm.amdgcn.exp2) and group by intrinsic ID, so their operands can be
+  // vectorized independently.
+  // FIXME: Extend for all non-vectorized functions.
+  SmallMapVector<std::pair<Intrinsic::ID, unsigned>, SmallVector<Value *, 4>, 4>
+      OpcodeGroups;
+
+  for (Instruction &I : *BB) {
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alexey-bataev wrote:

Why in a separate loop?

https://github.com/llvm/llvm-project/pull/189784