[Mlir-commits] [mlir] bf32bb7 - [mlir] Update approximation range for Tanh operation

[Eugene Zhulenev]

Author: Eugene Zhulenev
Date: 2021-10-18T10:57:31-07:00
New Revision: bf32bb7e056c9174cf1cf1a4bf78a339494aed95

URL: https://github.com/llvm/llvm-project/commit/bf32bb7e056c9174cf1cf1a4bf78a339494aed95
DIFF: https://github.com/llvm/llvm-project/commit/bf32bb7e056c9174cf1cf1a4bf78a339494aed95.diff

LOG: [mlir] Update approximation range for Tanh operation

Use wider range for approximating Tanh to match results computed in Eigen with AVX.

Reviewed By: cota

Differential Revision: https://reviews.llvm.org/D112011

Added: 
    

Modified: 
    mlir/lib/Dialect/Math/Transforms/PolynomialApproximation.cpp
    mlir/test/Dialect/Math/polynomial-approximation.mlir

Removed: 
    


################################################################################
diff  --git a/mlir/lib/Dialect/Math/Transforms/PolynomialApproximation.cpp b/mlir/lib/Dialect/Math/Transforms/PolynomialApproximation.cpp
index 94442dd605415..29fd0b6cda3ab 100644
--- a/mlir/lib/Dialect/Math/Transforms/PolynomialApproximation.cpp
+++ b/mlir/lib/Dialect/Math/Transforms/PolynomialApproximation.cpp
@@ -209,8 +209,8 @@ TanhApproximation::matchAndRewrite(math::TanhOp op,
   };
 
   // Clamp operand into [plusClamp, minusClamp] range.
-  Value minusClamp = bcast(f32Cst(builder, -7.9053111076354980f));
-  Value plusClamp = bcast(f32Cst(builder, 7.90531110763549805f));
+  Value minusClamp = bcast(f32Cst(builder, -7.99881172180175781f));
+  Value plusClamp = bcast(f32Cst(builder, 7.99881172180175781f));
   Value x = clamp(builder, op.operand(), minusClamp, plusClamp);
 
   // Mask for tiny values that are approximated with `operand`.

diff  --git a/mlir/test/Dialect/Math/polynomial-approximation.mlir b/mlir/test/Dialect/Math/polynomial-approximation.mlir
index 3ffc108534506..7d9ec8832acf1 100644
--- a/mlir/test/Dialect/Math/polynomial-approximation.mlir
+++ b/mlir/test/Dialect/Math/polynomial-approximation.mlir
@@ -248,8 +248,8 @@ func @log1p_vector(%arg0: vector<8xf32>) -> vector<8xf32> {
 
 // CHECK-LABEL:   func @tanh_scalar(
 // CHECK-SAME:                      %[[VAL_0:.*]]: f32) -> f32 {
-// CHECK:           %[[VAL_1:.*]] = arith.constant -7.90531111 : f32
-// CHECK:           %[[VAL_2:.*]] = arith.constant 7.90531111 : f32
+// CHECK:           %[[VAL_1:.*]] = arith.constant -7.99881172 : f32
+// CHECK:           %[[VAL_2:.*]] = arith.constant 7.99881172 : f32
 // CHECK:           %[[VAL_3:.*]] = arith.constant 4.000000e-04 : f32
 // CHECK:           %[[VAL_4:.*]] = arith.constant 0.00489352457 : f32
 // CHECK:           %[[VAL_5:.*]] = arith.constant 6.37261954E-4 : f32
@@ -290,7 +290,7 @@ func @tanh_scalar(%arg0: f32) -> f32 {
 
 // CHECK-LABEL:   func @tanh_vector(
 // CHECK-SAME:                      %[[VAL_0:.*]]: vector<8xf32>) -> vector<8xf32> {
-// CHECK:           %[[VAL_1:.*]] = arith.constant dense<-7.90531111> : vector<8xf32>
+// CHECK:           %[[VAL_1:.*]] = arith.constant dense<-7.99881172> : vector<8xf32>
 // CHECK-NOT:       tanh
 // CHECK-COUNT-2:   select
 // CHECK:           %[[VAL_33:.*]] = select