[Mlir-commits] [mlir] [mlir][arith] Add support for `extf`, `truncf` to `ArithToAPFloat` (PR #169275)

[Jakub Kuderski]

================
@@ -126,6 +138,53 @@ struct BinaryArithOpToAPFloatConversion final : OpRewritePattern<OpTy> {
   const char *APFloatName;
 };
 
+template <typename OpTy>
+struct FpToFpConversion final : OpRewritePattern<OpTy> {
+  FpToFpConversion(MLIRContext *context, SymbolOpInterface symTable,
+                   PatternBenefit benefit = 1)
+      : OpRewritePattern<OpTy>(context, benefit), symTable(symTable){};
+
+  LogicalResult matchAndRewrite(OpTy op,
+                                PatternRewriter &rewriter) const override {
+    // Get APFloat function from runtime library.
+    auto i32Type = IntegerType::get(symTable->getContext(), 32);
+    auto i64Type = IntegerType::get(symTable->getContext(), 64);
+    FailureOr<FuncOp> fn = lookupOrCreateApFloatFn(
+        rewriter, symTable, "convert", {i32Type, i32Type, i64Type});
+    if (failed(fn))
+      return fn;
+
+    rewriter.setInsertionPoint(op);
+    // Cast operands to 64-bit integers.
+    Location loc = op.getLoc();
+    auto inFloatTy = cast<FloatType>(op.getOperand().getType());
+    auto inIntWType = rewriter.getIntegerType(inFloatTy.getWidth());
+    auto int64Type = rewriter.getI64Type();
+    Value operandBits = arith::ExtUIOp::create(
+        rewriter, loc, int64Type,
+        arith::BitcastOp::create(rewriter, loc, inIntWType, op.getOperand()));
+
+    // Call APFloat function.
+    Value inSemValue = getSemanticsValue(rewriter, loc, inFloatTy);
+    auto outFloatTy = cast<FloatType>(op.getType());
+    Value outSemValue = getSemanticsValue(rewriter, loc, outFloatTy);
+    SmallVector<Value> params = {inSemValue, outSemValue, operandBits};
----------------
kuhar wrote:

nit: use a plain array if yo know the size?

https://github.com/llvm/llvm-project/pull/169275