[mlir][vector] fix: unroll vector.from_elements in gpu pipelines (llvm#154774)

### Problem

PR llvm#142944 introduced a new canonicalization pattern which caused
failures in the following GPU-related integration tests:

-
mlir/test/Integration/GPU/CUDA/TensorCore/sm80/transform-mma-sync-matmul-f16-f16-accum.mlir
-
mlir/test/Integration/GPU/CUDA/TensorCore/sm80/transform-mma-sync-matmul-f32.mlir

The issue occurs because the new canonicalization pattern can generate
multi-dimensional `vector.from_elements` operations (rank > 1), but the
GPU lowering pipelines were not equipped to handle these during the
conversion to LLVM.

### Fix

This PR adds `vector::populateVectorFromElementsLoweringPatterns` to the
GPU lowering passes that are integrated in `gpu-lower-to-nvvm-pipeline`:

- `GpuToLLVMConversionPass`: the general GPU-to-LLVM conversion pass.
- `LowerGpuOpsToNVVMOpsPass`: the NVVM-specific lowering pass.

Co-authored-by: Yang Bai <[email protected]>

Author: yangtetris

mlir/lib/Conversion/GPUCommon/GPUToLLVMConversion.cpp

@@ -532,6 +532,9 @@ void GpuToLLVMConversionPass::runOnOperation() {
     // Vector transfer ops with rank > 1 should be lowered with VectorToSCF.
     vector::populateVectorTransferLoweringPatterns(patterns,
                                                    /*maxTransferRank=*/1);
+    // Transform N-D vector.from_elements to 1-D vector.from_elements before
+    // conversion.
+    vector::populateVectorFromElementsLoweringPatterns(patterns);
     if (failed(applyPatternsGreedily(getOperation(), std::move(patterns))))
       return signalPassFailure();
   }

mlir/lib/Conversion/GPUToNVVM/LowerGpuOpsToNVVMOps.cpp

@@ -27,6 +27,7 @@
 #include "mlir/Dialect/Math/IR/Math.h"
 #include "mlir/Dialect/MemRef/IR/MemRef.h"
 #include "mlir/Dialect/NVGPU/IR/NVGPUDialect.h"
+#include "mlir/Dialect/Vector/Transforms/LoweringPatterns.h"
 #include "mlir/Transforms/DialectConversion.h"
 #include "mlir/Transforms/GreedyPatternRewriteDriver.h"
 
@@ -369,6 +370,9 @@ struct LowerGpuOpsToNVVMOpsPass final
     {
       RewritePatternSet patterns(m.getContext());
       populateGpuRewritePatterns(patterns);
+      // Transform N-D vector.from_elements to 1-D vector.from_elements before
+      // conversion.
+      vector::populateVectorFromElementsLoweringPatterns(patterns);
       if (failed(applyPatternsGreedily(m, std::move(patterns))))
         return signalPassFailure();
     }