void palXy2xy(double x1, double y1, double coeffs[6], double *x2, double *y2) {
  *x2 = coeffs[0] + coeffs[1] * x1 + coeffs[2] * y1;
  *y2 = coeffs[3] + coeffs[4] * x1 + coeffs[5] * y1;
}


x86 assembly (clang, -O0):
<palXy2xy>:
push   %rbp
mov    %rsp,%rbp
movsd  %xmm0,-0x8(%rbp)
movsd  %xmm1,-0x10(%rbp)
mov    %rdi,-0x18(%rbp)
mov    %rsi,-0x20(%rbp)
mov    %rdx,-0x28(%rbp)
mov    -0x18(%rbp),%rax
movsd  (%rax),%xmm0
mov    -0x18(%rbp),%rax
movsd  0x8(%rax),%xmm1
movsd  -0x8(%rbp),%xmm2
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
mov    -0x18(%rbp),%rax
movsd  0x10(%rax),%xmm0
movsd  -0x10(%rbp),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
mov    -0x20(%rbp),%rax
movsd  %xmm0,(%rax)
mov    -0x18(%rbp),%rax
movsd  0x18(%rax),%xmm0
mov    -0x18(%rbp),%rax
movsd  0x20(%rax),%xmm1
movsd  -0x8(%rbp),%xmm2
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
mov    -0x18(%rbp),%rax
movsd  0x28(%rax),%xmm0
movsd  -0x10(%rbp),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
mov    -0x28(%rbp),%rax
movsd  %xmm0,(%rax)
pop    %rbp
ret

x86 assembly (clang, -O2):
<palXy2xy>:
movsd  0x8(%rdi),%xmm2
mulsd  %xmm0,%xmm2
addsd  (%rdi),%xmm2
movsd  0x10(%rdi),%xmm3
mulsd  %xmm1,%xmm3
addsd  %xmm2,%xmm3
movsd  %xmm3,(%rsi)
mulsd  0x20(%rdi),%xmm0
addsd  0x18(%rdi),%xmm0
mulsd  0x28(%rdi),%xmm1
addsd  %xmm0,%xmm1
movsd  %xmm1,(%rdx)
ret

LLVM IR (-O0):
define void @palXy2xy(double %0, double %1, double* %2, double* %3, double* %4) {
%6 = alloca double
%7 = alloca double
%8 = alloca double*
%9 = alloca double*
%10 = alloca double*
store double %0, double* %6
store double %1, double* %7
store double* %2, double** %8
store double* %3, double** %9
store double* %4, double** %10
%11 = load double*, double** %8
%12 = getelementptr inbounds double, double* %11, i64 0
%13 = load double, double* %12
%14 = load double*, double** %8
%15 = getelementptr inbounds double, double* %14, i64 1
%16 = load double, double* %15
%17 = load double, double* %6
%18 = call double @llvm.fmuladd.f64(double %16, double %17, double %13)
%19 = load double*, double** %8
%20 = getelementptr inbounds double, double* %19, i64 2
%21 = load double, double* %20
%22 = load double, double* %7
%23 = call double @llvm.fmuladd.f64(double %21, double %22, double %18)
%24 = load double*, double** %9
store double %23, double* %24
%25 = load double*, double** %8
%26 = getelementptr inbounds double, double* %25, i64 3
%27 = load double, double* %26
%28 = load double*, double** %8
%29 = getelementptr inbounds double, double* %28, i64 4
%30 = load double, double* %29
%31 = load double, double* %6
%32 = call double @llvm.fmuladd.f64(double %30, double %31, double %27)
%33 = load double*, double** %8
%34 = getelementptr inbounds double, double* %33, i64 5
%35 = load double, double* %34
%36 = load double, double* %7
%37 = call double @llvm.fmuladd.f64(double %35, double %36, double %32)
%38 = load double*, double** %10
store double %37, double* %38
ret void
}

LLVM IR (-O2):
define void @palXy2xy(double %0, double %1, double* nocapture %2, double* nocapture writeonly %3, double* nocapture writeonly %4) {
%6 = load double, double* %2
%7 = getelementptr inbounds double, double* %2, i64 1
%8 = load double, double* %7
%9 = tail call double @llvm.fmuladd.f64(double %8, double %0, double %6)
%10 = getelementptr inbounds double, double* %2, i64 2
%11 = load double, double* %10
%12 = tail call double @llvm.fmuladd.f64(double %11, double %1, double %9)
store double %12, double* %3
%13 = getelementptr inbounds double, double* %2, i64 3
%14 = load double, double* %13
%15 = getelementptr inbounds double, double* %2, i64 4
%16 = load double, double* %15
%17 = tail call double @llvm.fmuladd.f64(double %16, double %0, double %14)
%18 = getelementptr inbounds double, double* %2, i64 5
%19 = load double, double* %18
%20 = tail call double @llvm.fmuladd.f64(double %19, double %1, double %17)
store double %20, double* %4
ret void
}