[Mlir-commits] [mlir] [mlir][math] Add conversions for acosh, asinh, atanh (PR #90718)

[Prashant Kumar]

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@@ -89,54 +89,14 @@ static LogicalResult convertCoshOp(math::CoshOp op, PatternRewriter &rewriter) {
   ImplicitLocOpBuilder b(op->getLoc(), rewriter);
   Value operand = op.getOperand();
   Type opType = operand.getType();
-  Value exp = b.create<math::ExpOp>(operand);
 
-  Value one = createFloatConst(op->getLoc(), opType, 1.0, rewriter);
-  Value nexp = b.create<arith::DivFOp>(one, exp);
+  Value exp = b.create<math::ExpOp>(operand);
+  Value neg = b.create<arith::NegFOp>(operand);
+  Value nexp = b.create<math::ExpOp>(neg);
   Value add = b.create<arith::AddFOp>(exp, nexp);
-  Value two = createFloatConst(op->getLoc(), opType, 2.0, rewriter);
-  Value div = b.create<arith::DivFOp>(add, two);
-  rewriter.replaceOp(op, div);
-  return success();
-}
-
-/// Expands tanh op into
-/// 1-exp^{-2x} / 1+exp^{-2x}
-/// To avoid overflow we exploit the reflection symmetry `tanh(-x) = -tanh(x)`.
-/// We compute a "signs" value which is -1 if input is negative and +1 if input
-/// is positive.  Then multiply the input by this value, guaranteeing that the
-/// result is positive, which also guarantees `exp^{-2x * sign(x)}` is in (0,
-/// 1]. Expand the computation on the input `x * sign(x)`, then multiply the
-/// result by `sign(x)` to retain sign of the real result.
-static LogicalResult convertTanhOp(math::TanhOp op, PatternRewriter &rewriter) {
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pashu123 wrote:

Thanks. I feel users can either utilize expand pattern or polynomial approximation according to their need. Some of the operations like exp, log isn't supported on custom hardware and hence users fall back to polynomial approximation. 

https://github.com/llvm/llvm-project/pull/90718