[flang] Implement asinpi (#150238)

Author: c8ef

flang/include/flang/Optimizer/Builder/IntrinsicCall.h

@@ -204,6 +204,7 @@ struct IntrinsicLibrary {
   fir::ExtendedValue
       genCommandArgumentCount(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   mlir::Value genAsind(mlir::Type, llvm::ArrayRef<mlir::Value>);
+  mlir::Value genAsinpi(mlir::Type, llvm::ArrayRef<mlir::Value>);
   fir::ExtendedValue genAssociated(mlir::Type,
                                    llvm::ArrayRef<fir::ExtendedValue>);
   mlir::Value genAtand(mlir::Type, llvm::ArrayRef<mlir::Value>);

flang/lib/Evaluate/intrinsics.cpp

@@ -359,6 +359,7 @@ static const IntrinsicInterface genericIntrinsicFunction[]{
     {"asin", {{"x", SameFloating}}, SameFloating},
     {"asind", {{"x", SameFloating}}, SameFloating},
     {"asinh", {{"x", SameFloating}}, SameFloating},
+    {"asinpi", {{"x", SameFloating}}, SameFloating},
     {"associated",
         {{"pointer", AnyPointer, Rank::anyOrAssumedRank, Optionality::required,
              common::Intent::In, {ArgFlag::canBeNullPointer}},

flang/lib/Optimizer/Builder/IntrinsicCall.cpp

@@ -279,6 +279,7 @@ static constexpr IntrinsicHandler handlers[]{
      {{{"mask", asValue}, {"pred", asValue}}},
      /*isElemental=*/false},
     {"asind", &I::genAsind},
+    {"asinpi", &I::genAsinpi},
     {"associated",
      &I::genAssociated,
      {{{"pointer", asInquired}, {"target", asInquired}}},
@@ -2845,6 +2846,21 @@ mlir::Value IntrinsicLibrary::genAsind(mlir::Type resultType,
   return mlir::arith::MulFOp::create(builder, loc, result, factor);
 }
 
+// ASINPI
+mlir::Value IntrinsicLibrary::genAsinpi(mlir::Type resultType,
+                                        llvm::ArrayRef<mlir::Value> args) {
+  assert(args.size() == 1);
+  mlir::MLIRContext *context = builder.getContext();
+  mlir::FunctionType ftype =
+      mlir::FunctionType::get(context, {resultType}, {args[0].getType()});
+  mlir::Value asin = getRuntimeCallGenerator("asin", ftype)(builder, loc, args);
+  llvm::APFloat inv_pi = llvm::APFloat(llvm::numbers::inv_pi);
+  mlir::Value dfactor =
+      builder.createRealConstant(loc, mlir::Float64Type::get(context), inv_pi);
+  mlir::Value factor = builder.createConvert(loc, resultType, dfactor);
+  return mlir::arith::MulFOp::create(builder, loc, asin, factor);
+}
+
 // ATAND, ATAN2D
 mlir::Value IntrinsicLibrary::genAtand(mlir::Type resultType,
                                        llvm::ArrayRef<mlir::Value> args) {

flang/test/Lower/Intrinsics/asinpi.f90

@@ -0,0 +1,26 @@
+! RUN: bbc -emit-fir -hlfir=false %s -o - | FileCheck %s --check-prefixes="CHECK,CHECK-FAST"
+! RUN: bbc --math-runtime=precise -emit-fir -hlfir=false %s -o - | FileCheck %s --check-prefixes="CHECK,CHECK-PRECISE"
+! RUN: %flang_fc1 -emit-fir -flang-deprecated-no-hlfir %s -o - | FileCheck %s --check-prefixes="CHECK,CHECK-FAST"
+
+function test_real4(x)
+  real :: x, test_real4
+  test_real4 = asinpi(x)
+end function
+
+! CHECK-LABEL: @_QPtest_real4
+! CHECK-PRECISE: %[[asin:.*]] = fir.call @asinf({{%[A-Za-z0-9._]+}}) fastmath<contract> : (f32) -> f32
+! CHECK-FAST: %[[asin:.*]] = math.asin %{{.*}} : f32
+! CHECK: %[[dpi:.*]] = arith.constant 0.31830988618379069 : f64
+! CHECK: %[[inv_pi:.*]] = fir.convert %[[dpi]] : (f64) -> f32
+! CHECK: %{{.*}} = arith.mulf %[[asin]], %[[inv_pi]] fastmath<contract> : f32
+
+function test_real8(x)
+  real(8) :: x, test_real8
+  test_real8 = asinpi(x)
+end function
+
+! CHECK-LABEL: @_QPtest_real8
+! CHECK-PRECISE: %[[asin:.*]] = fir.call @asin({{%[A-Za-z0-9._]+}}) fastmath<contract> : (f64) -> f64
+! CHECK-FAST: %[[asin:.*]] = math.asin %{{.*}} : f64
+! CHECK: %[[inv_pi:.*]] = arith.constant 0.31830988618379069 : f64
+! CHECK: %{{.*}} = arith.mulf %[[asin]], %[[inv_pi]] fastmath<contract> : f64