[flang][cuda] Add missing interface for __powf

[clementval]

__powf is defined in the CUDA Fortran programming guide but it's missing from our cudadevice module. Add the interface and bind name to __nv_powf

https://docs.nvidia.com/hpc-sdk/compilers/cuda-fortran-prog-guide/index.html#fortran-device-modules

https://docs.nvidia.com/cuda/libdevice-users-guide/__nv_powf.html#__nv_powf

[llvmbot]

@llvm/pr-subscribers-flang-fir-hlfir

Author: Valentin Clement (バレンタイン クレメン) (clementval)

Changes

__powf is defined in the CUDA Fortran programming guide but it's missing from our cudadevice module. Add the interface and bind name to __nv_powf

https://docs.nvidia.com/hpc-sdk/compilers/cuda-fortran-prog-guide/index.html#fortran-device-modules

https://docs.nvidia.com/cuda/libdevice-users-guide/__nv_powf.html#__nv_powf

---

Full diff: https://github.com/llvm/llvm-project/pull/153294.diff

2 Files Affected:

• (modified) flang/module/cudadevice.f90 (+7)
• (modified) flang/test/Lower/CUDA/cuda-device-proc.cuf (+4)

diff --git a/flang/module/cudadevice.f90 b/flang/module/cudadevice.f90
index 1b3c98b3e3f96..751a836f97237 100644
--- a/flang/module/cudadevice.f90
+++ b/flang/module/cudadevice.f90
@@ -764,6 +764,13 @@ attributes(device) real(8) function sinpi(x) bind(c,name='__nv_sinpi')
     end function
   end interface
 
+  interface
+    attributes(device) real(4) function __powf(x,y) bind(c, name='__nv_powf')
+      !dir$ ignore_tkr (d) x, y
+      real(4), value :: x, y
+    end function
+  end interface
+
   interface __brev
     attributes(device) integer function __brev(i) bind(c, name='__nv_brev')
       !dir$ ignore_tkr (d) i
diff --git a/flang/test/Lower/CUDA/cuda-device-proc.cuf b/flang/test/Lower/CUDA/cuda-device-proc.cuf
index 24600291b788a..04f35425a0846 100644
--- a/flang/test/Lower/CUDA/cuda-device-proc.cuf
+++ b/flang/test/Lower/CUDA/cuda-device-proc.cuf
@@ -58,6 +58,8 @@ attributes(global) subroutine devsub()
   res = __ffs(al)
   res = __brev(ai)
   resl = __brev(al)
+
+  af = __powf(af, af)
 end
 
 ! CHECK-LABEL: func.func @_QPdevsub() attributes {cuf.proc_attr = #cuf.cuda_proc<global>}
@@ -105,6 +107,8 @@ end
 ! CHECK: %{{.*}} = fir.call @__nv_brev(%{{.*}}) proc_attrs<bind_c> fastmath<contract> : (i32) -> i32
 ! CHECK: %{{.*}} = fir.call @__nv_brevll(%{{.*}}) proc_attrs<bind_c> fastmath<contract> : (i64) -> i64
 
+! CHECK: %{{.*}} = fir.call @__nv_powf(%{{.*}}, %{{.*}}) proc_attrs<bind_c> fastmath<contract> : (f32, f32) -> f32
+
 subroutine host1()
   integer, device :: a(32)
   integer, device :: ret