Kuznetsov Artyom lab 3 (option 1)

[Kuznetsov-Artyom]

implemented a plugin that combines two instructions (mul/add) into one muladd

Example:

// test.cpp
__m128d muladd_test2(__m128d a, __m128d b, __m128d c) {
  __m128d tmp = a * b;
  tmp = tmp + c;
  return tmp;
}

; test.ll
  define dso_local noundef <2 x double> @_Z12muladd_test2Dv2_dS_S_(<2 x double> noundef %a, <2 x double> noundef %b, <2 x double> noundef %c) local_unnamed_addr #2 {
  entry:
    %mul = fmul <2 x double> %a, %b
    %add = fadd <2 x double> %mul, %c
    ret <2 x double> %add
  }

# test_input.mir
  bb.0.entry:
    liveins: $xmm0, $xmm1, $xmm2
  
    renamable $xmm0 = nofpexcept MULPDrr killed renamable $xmm0, killed renamable $xmm1, implicit $mxcsr
    renamable $xmm0 = nofpexcept ADDPDrr killed renamable $xmm0, killed renamable $xmm2, implicit $mxcsr
    RET64 $xmm0

# test_outut.mir
iveins: $xmm0, $xmm1, $xmm2
  
    $xmm0 = VFMADD213PDZ128r $xmm0, $xmm1, $xmm2, implicit $mxcsr
    RET64 $xmm0