void transform44d3fas33d3f(double *m1, float *m2, float *m3) {
  register double m2r0 = m2[0];
  register double m2r1 = m2[1];
  register double m2r2 = m2[2];
  m3[0] = (float)(m1[0] * m2r0 + m1[1] * m2r1 + m1[2] * m2r2);
  m3[1] = (float)(m1[4] * m2r0 + m1[5] * m2r1 + m1[6] * m2r2);
  m3[2] = (float)(m1[8] * m2r0 + m1[9] * m2r1 + m1[10] * m2r2);
}


x86 assembly (clang, -O0):
<transform44d3fas33d3f>:
push   %rbp
mov    %rsp,%rbp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    %rdx,-0x18(%rbp)
mov    -0x10(%rbp),%rax
movss  (%rax),%xmm0
cvtss2sd %xmm0,%xmm0
movsd  %xmm0,-0x20(%rbp)
mov    -0x10(%rbp),%rax
movss  0x4(%rax),%xmm0
cvtss2sd %xmm0,%xmm0
movsd  %xmm0,-0x28(%rbp)
mov    -0x10(%rbp),%rax
movss  0x8(%rax),%xmm0
cvtss2sd %xmm0,%xmm0
movsd  %xmm0,-0x30(%rbp)
mov    -0x8(%rbp),%rax
movsd  (%rax),%xmm1
movsd  -0x20(%rbp),%xmm2
mov    -0x8(%rbp),%rax
movsd  0x8(%rax),%xmm0
mulsd  -0x28(%rbp),%xmm0
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
mov    -0x8(%rbp),%rax
movsd  0x10(%rax),%xmm0
movsd  -0x30(%rbp),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
cvtsd2ss %xmm0,%xmm0
mov    -0x18(%rbp),%rax
movss  %xmm0,(%rax)
mov    -0x8(%rbp),%rax
movsd  0x20(%rax),%xmm1
movsd  -0x20(%rbp),%xmm2
mov    -0x8(%rbp),%rax
movsd  0x28(%rax),%xmm0
mulsd  -0x28(%rbp),%xmm0
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
mov    -0x8(%rbp),%rax
movsd  0x30(%rax),%xmm0
movsd  -0x30(%rbp),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
cvtsd2ss %xmm0,%xmm0
mov    -0x18(%rbp),%rax
movss  %xmm0,0x4(%rax)
mov    -0x8(%rbp),%rax
movsd  0x40(%rax),%xmm1
movsd  -0x20(%rbp),%xmm2
mov    -0x8(%rbp),%rax
movsd  0x48(%rax),%xmm0
mulsd  -0x28(%rbp),%xmm0
mulsd  %xmm2,%xmm1
addsd  %xmm0,%xmm1
mov    -0x8(%rbp),%rax
movsd  0x50(%rax),%xmm0
movsd  -0x30(%rbp),%xmm2
mulsd  %xmm2,%xmm0
addsd  %xmm1,%xmm0
cvtsd2ss %xmm0,%xmm0
mov    -0x18(%rbp),%rax
movss  %xmm0,0x8(%rax)
pop    %rbp
ret

x86 assembly (clang, -O2):
<transform44d3fas33d3f>:
movss  (%rsi),%xmm0
movss  0x4(%rsi),%xmm1
cvtss2sd %xmm0,%xmm0
cvtss2sd %xmm1,%xmm2
movss  0x8(%rsi),%xmm1
cvtss2sd %xmm1,%xmm1
movsd  0x8(%rdi),%xmm3
mulsd  %xmm2,%xmm3
movsd  (%rdi),%xmm4
mulsd  %xmm0,%xmm4
addsd  %xmm3,%xmm4
movsd  0x10(%rdi),%xmm3
mulsd  %xmm1,%xmm3
addsd  %xmm4,%xmm3
cvtsd2ss %xmm3,%xmm3
movss  %xmm3,(%rdx)
movsd  0x28(%rdi),%xmm3
mulsd  %xmm2,%xmm3
movsd  0x20(%rdi),%xmm4
mulsd  %xmm0,%xmm4
addsd  %xmm3,%xmm4
movsd  0x30(%rdi),%xmm3
mulsd  %xmm1,%xmm3
addsd  %xmm4,%xmm3
cvtsd2ss %xmm3,%xmm3
movss  %xmm3,0x4(%rdx)
mulsd  0x48(%rdi),%xmm2
mulsd  0x40(%rdi),%xmm0
addsd  %xmm2,%xmm0
mulsd  0x50(%rdi),%xmm1
addsd  %xmm0,%xmm1
xorps  %xmm0,%xmm0
cvtsd2ss %xmm1,%xmm0
movss  %xmm0,0x8(%rdx)
ret

LLVM IR (-O0):
define void @transform44d3fas33d3f(double* %0, float* %1, float* %2) {
%4 = alloca double*
%5 = alloca float*
%6 = alloca float*
%7 = alloca double
%8 = alloca double
%9 = alloca double
store double* %0, double** %4
store float* %1, float** %5
store float* %2, float** %6
%10 = load float*, float** %5
%11 = getelementptr inbounds float, float* %10, i64 0
%12 = load float, float* %11
%13 = fpext float %12 to double
store double %13, double* %7
%14 = load float*, float** %5
%15 = getelementptr inbounds float, float* %14, i64 1
%16 = load float, float* %15
%17 = fpext float %16 to double
store double %17, double* %8
%18 = load float*, float** %5
%19 = getelementptr inbounds float, float* %18, i64 2
%20 = load float, float* %19
%21 = fpext float %20 to double
store double %21, double* %9
%22 = load double*, double** %4
%23 = getelementptr inbounds double, double* %22, i64 0
%24 = load double, double* %23
%25 = load double, double* %7
%26 = load double*, double** %4
%27 = getelementptr inbounds double, double* %26, i64 1
%28 = load double, double* %27
%29 = load double, double* %8
%30 = fmul double %28, %29
%31 = call double @llvm.fmuladd.f64(double %24, double %25, double %30)
%32 = load double*, double** %4
%33 = getelementptr inbounds double, double* %32, i64 2
%34 = load double, double* %33
%35 = load double, double* %9
%36 = call double @llvm.fmuladd.f64(double %34, double %35, double %31)
%37 = fptrunc double %36 to float
%38 = load float*, float** %6
%39 = getelementptr inbounds float, float* %38, i64 0
store float %37, float* %39
%40 = load double*, double** %4
%41 = getelementptr inbounds double, double* %40, i64 4
%42 = load double, double* %41
%43 = load double, double* %7
%44 = load double*, double** %4
%45 = getelementptr inbounds double, double* %44, i64 5
%46 = load double, double* %45
%47 = load double, double* %8
%48 = fmul double %46, %47
%49 = call double @llvm.fmuladd.f64(double %42, double %43, double %48)
%50 = load double*, double** %4
%51 = getelementptr inbounds double, double* %50, i64 6
%52 = load double, double* %51
%53 = load double, double* %9
%54 = call double @llvm.fmuladd.f64(double %52, double %53, double %49)
%55 = fptrunc double %54 to float
%56 = load float*, float** %6
%57 = getelementptr inbounds float, float* %56, i64 1
store float %55, float* %57
%58 = load double*, double** %4
%59 = getelementptr inbounds double, double* %58, i64 8
%60 = load double, double* %59
%61 = load double, double* %7
%62 = load double*, double** %4
%63 = getelementptr inbounds double, double* %62, i64 9
%64 = load double, double* %63
%65 = load double, double* %8
%66 = fmul double %64, %65
%67 = call double @llvm.fmuladd.f64(double %60, double %61, double %66)
%68 = load double*, double** %4
%69 = getelementptr inbounds double, double* %68, i64 10
%70 = load double, double* %69
%71 = load double, double* %9
%72 = call double @llvm.fmuladd.f64(double %70, double %71, double %67)
%73 = fptrunc double %72 to float
%74 = load float*, float** %6
%75 = getelementptr inbounds float, float* %74, i64 2
store float %73, float* %75
ret void
}

LLVM IR (-O2):
define void @transform44d3fas33d3f(double* nocapture %0, float* nocapture %1, float* nocapture writeonly %2) {
%4 = load float, float* %1
%5 = fpext float %4 to double
%6 = getelementptr inbounds float, float* %1, i64 1
%7 = load float, float* %6
%8 = fpext float %7 to double
%9 = getelementptr inbounds float, float* %1, i64 2
%10 = load float, float* %9
%11 = fpext float %10 to double
%12 = load double, double* %0
%13 = getelementptr inbounds double, double* %0, i64 1
%14 = load double, double* %13
%15 = fmul double %14, %8
%16 = tail call double @llvm.fmuladd.f64(double %12, double %5, double %15)
%17 = getelementptr inbounds double, double* %0, i64 2
%18 = load double, double* %17
%19 = tail call double @llvm.fmuladd.f64(double %18, double %11, double %16)
%20 = fptrunc double %19 to float
store float %20, float* %2
%21 = getelementptr inbounds double, double* %0, i64 4
%22 = load double, double* %21
%23 = getelementptr inbounds double, double* %0, i64 5
%24 = load double, double* %23
%25 = fmul double %24, %8
%26 = tail call double @llvm.fmuladd.f64(double %22, double %5, double %25)
%27 = getelementptr inbounds double, double* %0, i64 6
%28 = load double, double* %27
%29 = tail call double @llvm.fmuladd.f64(double %28, double %11, double %26)
%30 = fptrunc double %29 to float
%31 = getelementptr inbounds float, float* %2, i64 1
store float %30, float* %31
%32 = getelementptr inbounds double, double* %0, i64 8
%33 = load double, double* %32
%34 = getelementptr inbounds double, double* %0, i64 9
%35 = load double, double* %34
%36 = fmul double %35, %8
%37 = tail call double @llvm.fmuladd.f64(double %33, double %5, double %36)
%38 = getelementptr inbounds double, double* %0, i64 10
%39 = load double, double* %38
%40 = tail call double @llvm.fmuladd.f64(double %39, double %11, double %37)
%41 = fptrunc double %40 to float
%42 = getelementptr inbounds float, float* %2, i64 2
store float %41, float* %42
ret void
}