From 4a8f1d670f6135eaf4fabb6f5ed677e6cb571464 Mon Sep 17 00:00:00 2001
From: Tarun Prabhu <tarun@lanl.gov>
Date: Thu, 11 Jul 2024 07:24:42 -0600
Subject: [PATCH] [flang] Lower 2-argument F2008 atan intrinsic

Implement lowering and testing of the atan(y,x) form of the atan
intrinsic. Since the standard specifies that the behavior of this form
is identical to the atan2 intrinsic, everything is lowered to atan2.

In addition to tests for the atan(y,x) intrinsic, tests for the atan(x)
intrinsic were also added/updated.
---
 flang/lib/Optimizer/Builder/IntrinsicCall.cpp |  6 ++
 flang/test/Lower/Intrinsics/atan.f90          | 55 +++++++++++++++++++
 flang/test/Lower/Intrinsics/atan_real16.f90   | 17 +++++-
 3 files changed, 75 insertions(+), 3 deletions(-)
 create mode 100644 flang/test/Lower/Intrinsics/atan.f90

diff --git a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
index f4541bf30676a6..fe7605d8ce4ba7 100644
--- a/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
+++ b/flang/lib/Optimizer/Builder/IntrinsicCall.cpp
@@ -1059,6 +1059,12 @@ static constexpr MathOperation mathOperations[] = {
     {"atan", "catan", genFuncType<Ty::Complex<8>, Ty::Complex<8>>, genLibCall},
     {"atan", RTNAME_STRING(CAtanF128), FuncTypeComplex16Complex16,
      genLibF128Call},
+    {"atan", "atan2f", genFuncType<Ty::Real<4>, Ty::Real<4>, Ty::Real<4>>,
+     genMathOp<mlir::math::Atan2Op>},
+    {"atan", "atan2", genFuncType<Ty::Real<8>, Ty::Real<8>, Ty::Real<8>>,
+     genMathOp<mlir::math::Atan2Op>},
+    {"atan", RTNAME_STRING(Atan2F128), FuncTypeReal16Real16Real16,
+     genLibF128Call},
     {"atan2", "atan2f", genFuncType<Ty::Real<4>, Ty::Real<4>, Ty::Real<4>>,
      genMathOp<mlir::math::Atan2Op>},
     {"atan2", "atan2", genFuncType<Ty::Real<8>, Ty::Real<8>, Ty::Real<8>>,
diff --git a/flang/test/Lower/Intrinsics/atan.f90 b/flang/test/Lower/Intrinsics/atan.f90
new file mode 100644
index 00000000000000..cf595b4d95d1d4
--- /dev/null
+++ b/flang/test/Lower/Intrinsics/atan.f90
@@ -0,0 +1,55 @@
+! Check that correct runtime calls are used.
+! RUN: bbc --math-runtime=precise -emit-fir %s -o - | FileCheck --check-prefixes=CHECK-RUNTIME %s
+! RUN: %flang_fc1 -mllvm -math-runtime=precise -emit-fir %s -o - | FileCheck --check-prefixes=CHECK-RUNTIME %s
+
+! Check that the correct math dialect operations are used.
+! RUN: bbc -emit-fir %s -o - | FileCheck --check-prefixes=CHECK-NORMAL %s
+! RUN: %flang_fc1 -emit-fir %s -o - | FileCheck --check-prefixes=CHECK-NORMAL %s
+
+function test_real4(x)
+  real :: x, test_real4
+  test_real4 = atan(x)
+end function
+
+! CHECK-RUNTIME: {{%[A-Za-z0-9._]+}} = fir.call @atanf({{.*}}) {{.*}}: (f32) -> f32
+! CHECK-NORMAL: {{%[A-Za-z0-9._]+}} = math.atan {{.*}} {{.*}}: f32
+
+function test_real8(x)
+  real(8) :: x, test_real8
+  test_real8 = atan(x)
+end function
+
+! CHECK-RUNTIME: {{%[A-Za-z0-9._]+}} = fir.call @atan({{.*}}) {{.*}}: (f64) -> f64
+! CHECK-NORMAL: {{%[A-Za-z0-9._]+}} = math.atan {{.*}} {{.*}}: f64
+
+function test_complex4(x)
+  complex :: x, test_complex4
+  test_complex4 = atan(x)
+end function
+
+! CHECK-RUNTIME: {{%[A-Za-z0-9._]+}} = fir.call @catanf({{.*}}) {{.*}}: (!fir.complex<4>) -> !fir.complex<4>
+! CHECK-NORMAL: {{%[A-Za-z0-9._]+}} = fir.call @catanf({{.*}}) {{.*}}: (!fir.complex<4>) -> !fir.complex<4>
+
+function test_complex8(x)
+  complex(kind=8) :: x, test_complex8
+  test_complex8 = atan(x)
+end function
+
+! CHECK-RUNTIME: {{%[A-Za-z0-9._]+}} = fir.call @catan({{.*}}) {{.*}}: (!fir.complex<8>) -> !fir.complex<8>
+! CHECK-NORMAL: {{%[A-Za-z0-9._]+}} = fir.call @catan({{.*}}) {{.*}}: (!fir.complex<8>) -> !fir.complex<8>
+
+function test_real4_2(y, x)
+  real :: y, x, test_real4_2
+  test_real4_2 = atan(y, x)
+end function
+
+! CHECK-RUNTIME: {{%[A-Za-z0-9._]+}} = fir.call @atan2f({{.*}}) {{.*}}: (f32, f32) -> f32
+! CHECK-NORMAL: {{%[A-Za-z0-9._]+}} = math.atan2 {{.*}} {{.*}}: f32
+
+function test_real8_2(y, x)
+  real(8) :: y, x, test_real8_2
+  test_real8_2 = atan(y, x)
+end function
+
+! CHECK-RUNTIME: {{%[A-Za-z0-9._]+}} = fir.call @atan2({{.*}}) {{.*}}: (f64, f64) -> f64
+! CHECK-NORMAL: {{%[A-Za-z0-9._]+}} = math.atan2 {{.*}} {{.*}}: f64
diff --git a/flang/test/Lower/Intrinsics/atan_real16.f90 b/flang/test/Lower/Intrinsics/atan_real16.f90
index 5c0c262711c61b..3ae037307c32b6 100644
--- a/flang/test/Lower/Intrinsics/atan_real16.f90
+++ b/flang/test/Lower/Intrinsics/atan_real16.f90
@@ -3,7 +3,18 @@
 ! RUN: bbc --math-runtime=precise -emit-fir %s -o - | FileCheck %s
 ! RUN: %flang_fc1 -emit-fir %s -o - | FileCheck %s
 
+function test_real16(x)
+  real(16) :: x, test_real16
+  test_real16 = atan(x)
+end function real16
+
+! CHECK-LABEL: @_QPtest_real16
 ! CHECK: fir.call @_FortranAAtanF128({{.*}}){{.*}}: (f128) -> f128
-  real(16) :: a, b
-  b = atan(a)
-end
+
+function test_real16_2(y, x)
+  real(16) :: y, x, test_real16
+  test_real16 = atan(y, x)
+end function real16_2
+
+! CHECK-LABEL: @_QPtest_real16
+! CHECK: fir.call @_FortranAAtan2F128({{.*}}){{.*}}: (f128, f128) -> f128