[Mlir-commits] [mlir] [mlir][spirv] Add pattern matching for arith.index_cast index to i1 for ArithToSPIRV (PR #156031)

[Md Abdullah Shahneous Bari]

================
@@ -607,6 +607,38 @@ struct UIToFPI1Pattern final : public OpConversionPattern<arith::UIToFPOp> {
   }
 };
 
+//===----------------------------------------------------------------------===//
+// IndexCastOp
+//===----------------------------------------------------------------------===//
+
+/// Converts arith.index_cast to spirv.Select if the type of source is index.
+struct IndexCastIndexI1Pattern final
+    : public OpConversionPattern<arith::IndexCastOp> {
+  using OpConversionPattern::OpConversionPattern;
+
+  LogicalResult
+  matchAndRewrite(arith::IndexCastOp op, OpAdaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+    Type srcType = adaptor.getOperands().front().getType();
+    // Indexes have already been converted to its respective spirv type:
+    Type indexType = getTypeConverter<SPIRVTypeConverter>()->getIndexType();
+    if (srcType != indexType || !op.getType().isInteger(1))
+      return failure();
+
+    Type dstType = rewriter.getI1Type();
+    Location loc = op.getLoc();
+    Value zero = spirv::ConstantOp::getZero(dstType, loc, rewriter);
+    Value one = spirv::ConstantOp::getOne(dstType, loc, rewriter);
+    Value zeroIdx = spirv::ConstantOp::getZero(srcType, loc, rewriter);
+    auto isZero = spirv::IEqualOp::create(rewriter, loc, dstType, zeroIdx,
+                                          adaptor.getOperands().front());
+    // spriv.IEqual outputs i32, spirv.Select is used to truncate to i1:
----------------
mshahneo wrote:

Hi @ianayl ,

spirv.IEqual itself actually returns a i1, spirv.Select is used here to select which i1 value to convert to.
I think you can remove this comment.

https://github.com/llvm/llvm-project/pull/156031