[MLIR][GPUToLLVMSPV] Update ConvertGpuOpsToLLVMSPVOps's option (#118818)

## Description

This PR updates the `ConvertGpuOpsToLLVMSPVOps`'s option by replacing
the `index-bitwidth` with a boolean option `use-64bit-index` (similar to
the `ConvertGPUToSPIRV` option).

The reason for this modification is because the
`ConvertGpuOpsToLLVMSPVOps`:
> Generate LLVM operations to be ingested by a SPIR-V backend for gpu
operations

In the context of SPIR-V specifications only two physical addressing
models are allowed: `Physical32` and `Physical64`.

This change guarantees output sanity by preventing invalid or
unsupported index bitwidths from being specified.

Author: jle-quel

mlir/include/mlir/Conversion/Passes.td

@@ -553,9 +553,9 @@ def ConvertGpuOpsToLLVMSPVOps : Pass<"convert-gpu-to-llvm-spv", "gpu::GPUModuleO
     "Generate LLVM operations to be ingested by a SPIR-V backend for gpu operations";
   let dependentDialects = ["LLVM::LLVMDialect"];
   let options = [
-    Option<"indexBitwidth", "index-bitwidth", "unsigned",
-           /*default=kDeriveIndexBitwidthFromDataLayout*/"0",
-           "Bitwidth of the index type, 0 to use size of machine word">,
+    Option<"use64bitIndex", "use-64bit-index",
+           "bool", /*default=*/"false",
+           "Use 64-bit integers to convert index types">,
   ];
 }
 

mlir/lib/Conversion/GPUToLLVMSPV/GPUToLLVMSPV.cpp

@@ -409,9 +409,7 @@ struct GPUToLLVMSPVConversionPass final
     RewritePatternSet patterns(context);
 
     LowerToLLVMOptions options(context);
-    if (indexBitwidth != kDeriveIndexBitwidthFromDataLayout)
-      options.overrideIndexBitwidth(indexBitwidth);
-
+    options.overrideIndexBitwidth(this->use64bitIndex ? 64 : 32);
     LLVMTypeConverter converter(context, options);
     LLVMConversionTarget target(*context);
 

mlir/test/Conversion/GPUToLLVMSPV/gpu-to-llvm-spv.mlir

@@ -1,6 +1,8 @@
-// RUN: mlir-opt -pass-pipeline="builtin.module(gpu.module(convert-gpu-to-llvm-spv))" -split-input-file -verify-diagnostics %s \
+// RUN: mlir-opt -pass-pipeline="builtin.module(gpu.module(convert-gpu-to-llvm-spv{use-64bit-index=true}))" -split-input-file -verify-diagnostics %s \
 // RUN: | FileCheck --check-prefixes=CHECK-64,CHECK %s
-// RUN: mlir-opt -pass-pipeline="builtin.module(gpu.module(convert-gpu-to-llvm-spv{index-bitwidth=32}))" -split-input-file -verify-diagnostics %s \
+// RUN: mlir-opt -pass-pipeline="builtin.module(gpu.module(convert-gpu-to-llvm-spv))" -split-input-file -verify-diagnostics %s \
+// RUN: | FileCheck --check-prefixes=CHECK-32,CHECK %s
+// RUN: mlir-opt -pass-pipeline="builtin.module(gpu.module(convert-gpu-to-llvm-spv{use-64bit-index=false}))" -split-input-file -verify-diagnostics %s \
 // RUN: | FileCheck --check-prefixes=CHECK-32,CHECK %s
 
 gpu.module @builtins {