float function16(long double a, double b, short int c, long double d, double e,
                 long double f, short int g, double h, double i, float j) {
  return a + b + c + d + e + f + g + h + i + j;
}


x86 assembly (clang, -O0):
<function16>:
push   %rbp
mov    %rsp,%rbp
mov    %si,%ax
mov    %di,%cx
fldt   0x30(%rbp)
fldt   0x20(%rbp)
fldt   0x10(%rbp)
fstpt  -0x10(%rbp)
movsd  %xmm0,-0x18(%rbp)
mov    %cx,-0x1a(%rbp)
fstpt  -0x30(%rbp)
movsd  %xmm1,-0x38(%rbp)
fstpt  -0x50(%rbp)
mov    %ax,-0x52(%rbp)
movsd  %xmm2,-0x60(%rbp)
movsd  %xmm3,-0x68(%rbp)
movss  %xmm4,-0x6c(%rbp)
fldt   -0x10(%rbp)
fldl   -0x18(%rbp)
faddp  %st,%st(1)
movswl -0x1a(%rbp),%eax
mov    %eax,-0x74(%rbp)
fildl  -0x74(%rbp)
faddp  %st,%st(1)
fldt   -0x30(%rbp)
faddp  %st,%st(1)
fldl   -0x38(%rbp)
faddp  %st,%st(1)
fldt   -0x50(%rbp)
faddp  %st,%st(1)
movswl -0x52(%rbp),%eax
mov    %eax,-0x70(%rbp)
fildl  -0x70(%rbp)
faddp  %st,%st(1)
fldl   -0x60(%rbp)
faddp  %st,%st(1)
fldl   -0x68(%rbp)
faddp  %st,%st(1)
flds   -0x6c(%rbp)
faddp  %st,%st(1)
fstps  -0x78(%rbp)
movss  -0x78(%rbp),%xmm0
pop    %rbp
ret

x86 assembly (clang, -O2):
<function16>:
fldt   0x28(%rsp)
fldt   0x8(%rsp)
movsd  %xmm0,-0x8(%rsp)
faddl  -0x8(%rsp)
fldt   0x18(%rsp)
mov    %di,-0x2c(%rsp)
fxch   %st(1)
fiadds -0x2c(%rsp)
faddp  %st,%st(1)
movsd  %xmm1,-0x10(%rsp)
faddl  -0x10(%rsp)
faddp  %st,%st(1)
mov    %si,-0x2a(%rsp)
fiadds -0x2a(%rsp)
movsd  %xmm2,-0x18(%rsp)
faddl  -0x18(%rsp)
movsd  %xmm3,-0x20(%rsp)
faddl  -0x20(%rsp)
movss  %xmm4,-0x24(%rsp)
fadds  -0x24(%rsp)
fstps  -0x28(%rsp)
movss  -0x28(%rsp),%xmm0
ret

LLVM IR (-O0):
define float @function16(x86_fp80 %0, double %1, i16 signext %2, x86_fp80 %3, double %4, x86_fp80 %5, i16 signext %6, double %7, double %8, float %9) {
%11 = alloca x86_fp80
%12 = alloca double
%13 = alloca i16
%14 = alloca x86_fp80
%15 = alloca double
%16 = alloca x86_fp80
%17 = alloca i16
%18 = alloca double
%19 = alloca double
%20 = alloca float
store x86_fp80 %0, x86_fp80* %11
store double %1, double* %12
store i16 %2, i16* %13
store x86_fp80 %3, x86_fp80* %14
store double %4, double* %15
store x86_fp80 %5, x86_fp80* %16
store i16 %6, i16* %17
store double %7, double* %18
store double %8, double* %19
store float %9, float* %20
%21 = load x86_fp80, x86_fp80* %11
%22 = load double, double* %12
%23 = fpext double %22 to x86_fp80
%24 = fadd x86_fp80 %21, %23
%25 = load i16, i16* %13
%26 = sext i16 %25 to i32
%27 = sitofp i32 %26 to x86_fp80
%28 = fadd x86_fp80 %24, %27
%29 = load x86_fp80, x86_fp80* %14
%30 = fadd x86_fp80 %28, %29
%31 = load double, double* %15
%32 = fpext double %31 to x86_fp80
%33 = fadd x86_fp80 %30, %32
%34 = load x86_fp80, x86_fp80* %16
%35 = fadd x86_fp80 %33, %34
%36 = load i16, i16* %17
%37 = sext i16 %36 to i32
%38 = sitofp i32 %37 to x86_fp80
%39 = fadd x86_fp80 %35, %38
%40 = load double, double* %18
%41 = fpext double %40 to x86_fp80
%42 = fadd x86_fp80 %39, %41
%43 = load double, double* %19
%44 = fpext double %43 to x86_fp80
%45 = fadd x86_fp80 %42, %44
%46 = load float, float* %20
%47 = fpext float %46 to x86_fp80
%48 = fadd x86_fp80 %45, %47
%49 = fptrunc x86_fp80 %48 to float
ret float %49
}

LLVM IR (-O2):
define float @function16(x86_fp80 %0, double %1, i16 signext %2, x86_fp80 %3, double %4, x86_fp80 %5, i16 signext %6, double %7, double %8, float %9) {
%11 = fpext double %1 to x86_fp80
%12 = fadd x86_fp80 %11, %0
%13 = sitofp i16 %2 to x86_fp80
%14 = fadd x86_fp80 %12, %13
%15 = fadd x86_fp80 %14, %3
%16 = fpext double %4 to x86_fp80
%17 = fadd x86_fp80 %15, %16
%18 = fadd x86_fp80 %17, %5
%19 = sitofp i16 %6 to x86_fp80
%20 = fadd x86_fp80 %18, %19
%21 = fpext double %7 to x86_fp80
%22 = fadd x86_fp80 %20, %21
%23 = fpext double %8 to x86_fp80
%24 = fadd x86_fp80 %22, %23
%25 = fpext float %9 to x86_fp80
%26 = fadd x86_fp80 %24, %25
%27 = fptrunc x86_fp80 %26 to float
ret float %27
}