As per review comment from Trevor G

Author: lei137

llvm/lib/IR/RuntimeLibcalls.cpp

@@ -82,6 +82,7 @@ void RuntimeLibcallsInfo::initLibcalls(const Triple &TT) {
     setLibcallName(RTLIB::POWI_F128, "__powikf2");
     setLibcallName(RTLIB::FPEXT_F32_F128, "__extendsfkf2");
     setLibcallName(RTLIB::FPEXT_F64_F128, "__extenddfkf2");
+    setLibcallName(RTLIB::FPROUND_F128_F16, "__trunckfhf2");
     setLibcallName(RTLIB::FPROUND_F128_F32, "__trunckfsf2");
     setLibcallName(RTLIB::FPROUND_F128_F64, "__trunckfdf2");
     setLibcallName(RTLIB::FPTOSINT_F128_I32, "__fixkfsi");

llvm/test/CodeGen/PowerPC/f128-conv.ll

@@ -1347,7 +1347,7 @@ define half @trunc(fp128 %a) nounwind {
 ; CHECK-NEXT:    mflr r0
 ; CHECK-NEXT:    stdu r1, -32(r1)
 ; CHECK-NEXT:    std r0, 48(r1)
-; CHECK-NEXT:    bl __trunctfhf2
+; CHECK-NEXT:    bl __trunckfhf2
 ; CHECK-NEXT:    nop
 ; CHECK-NEXT:    clrlwi r3, r3, 16
 ; CHECK-NEXT:    mtfprwz f0, r3
@@ -1362,7 +1362,7 @@ define half @trunc(fp128 %a) nounwind {
 ; CHECK-P8-NEXT:    mflr r0
 ; CHECK-P8-NEXT:    stdu r1, -32(r1)
 ; CHECK-P8-NEXT:    std r0, 48(r1)
-; CHECK-P8-NEXT:    bl __trunctfhf2
+; CHECK-P8-NEXT:    bl __trunckfhf2
 ; CHECK-P8-NEXT:    nop
 ; CHECK-P8-NEXT:    clrldi r3, r3, 48
 ; CHECK-P8-NEXT:    bl __extendhfsf2

llvm/test/CodeGen/PowerPC/fp128-libcalls.ll

@@ -55,7 +55,7 @@ define fp128 @extenddfkf2(double %a) {
 
 define half @trunctfhf2(fp128 %a) {
 ; CHECK-LABEL: trunctfhf2:
-; CHECK: __trunctfhf2
+; CHECK: __trunckfhf2
 entry:
   %i = fptrunc fp128 %a to half
   ret half %i