[AMDGPU] Allow the __builtin_flt_rounds functions on AMDGPU (#90994)

Summary:
Previous patches added support for the LLVM rounding intrinsic
functions. This patch allows them to me emitted using the clang builtins
when targeting AMDGPU.

Author: jhuber6

clang/lib/Sema/SemaChecking.cpp

@@ -2533,18 +2533,18 @@ Sema::CheckBuiltinFunctionCall(FunctionDecl *FDecl, unsigned BuiltinID,
   case Builtin::BI_bittestandset64:
   case Builtin::BI_interlockedbittestandreset64:
   case Builtin::BI_interlockedbittestandset64:
-    if (CheckBuiltinTargetInSupported(*this, BuiltinID, TheCall,
-                                      {llvm::Triple::x86_64, llvm::Triple::arm,
-                                       llvm::Triple::thumb,
-                                       llvm::Triple::aarch64}))
+    if (CheckBuiltinTargetInSupported(
+            *this, BuiltinID, TheCall,
+            {llvm::Triple::x86_64, llvm::Triple::arm, llvm::Triple::thumb,
+             llvm::Triple::aarch64, llvm::Triple::amdgcn}))
       return ExprError();
     break;
 
   case Builtin::BI__builtin_set_flt_rounds:
-    if (CheckBuiltinTargetInSupported(*this, BuiltinID, TheCall,
-                                      {llvm::Triple::x86, llvm::Triple::x86_64,
-                                       llvm::Triple::arm, llvm::Triple::thumb,
-                                       llvm::Triple::aarch64}))
+    if (CheckBuiltinTargetInSupported(
+            *this, BuiltinID, TheCall,
+            {llvm::Triple::x86, llvm::Triple::x86_64, llvm::Triple::arm,
+             llvm::Triple::thumb, llvm::Triple::aarch64, llvm::Triple::amdgcn}))
       return ExprError();
     break;
 

clang/test/CodeGenOpenCL/builtins-amdgcn.cl

@@ -839,6 +839,18 @@ unsigned test_wavefrontsize() {
   return __builtin_amdgcn_wavefrontsize();
 }
 
+// CHECK-LABEL test_flt_rounds(
+unsigned test_flt_rounds() {
+
+  // CHECK: call i32 @llvm.get.rounding()
+  unsigned mode = __builtin_flt_rounds();
+
+  // CHECK: call void @llvm.set.rounding(i32 %0)
+  __builtin_set_flt_rounds(mode);
+
+  return mode;
+}
+
 // CHECK-LABEL test_get_fpenv(
 unsigned long test_get_fpenv() {
   // CHECK: call i64 @llvm.get.fpenv.i64()