llvm/test/CodeGen/X86/machine-combiner.ll

; RUN: llc -mtriple=x86_64-unknown-unknown -mcpu=x86-64 -mattr=sse -enable-unsafe-fp-math < %s | FileCheck %s --check-prefix=SSE
; RUN: llc -mtriple=x86_64-unknown-unknown -mcpu=x86-64 -mattr=avx -enable-unsafe-fp-math < %s | FileCheck %s --check-prefix=AVX

; Verify that the first two adds are independent regardless of how the inputs are
; commuted. The destination registers are used as source registers for the third add.

define float @reassociate_adds1(float %x0, float %x1, float %x2, float %x3) {
; SSE-LABEL: reassociate_adds1:
; SSE:       # BB#0:
; SSE-NEXT:    addss %xmm1, %xmm0
; SSE-NEXT:    addss %xmm3, %xmm2
; SSE-NEXT:    addss %xmm2, %xmm0
; SSE-NEXT:    retq
;
; AVX-LABEL: reassociate_adds1:
; AVX:       # BB#0:
; AVX-NEXT:    vaddss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    vaddss %xmm3, %xmm2, %xmm1
; AVX-NEXT:    vaddss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    retq
  %t0 = fadd float %x0, %x1
  %t1 = fadd float %t0, %x2
  %t2 = fadd float %t1, %x3
  ret float %t2
}

define float @reassociate_adds2(float %x0, float %x1, float %x2, float %x3) {
; SSE-LABEL: reassociate_adds2:
; SSE:       # BB#0:
; SSE-NEXT:    addss %xmm1, %xmm0
; SSE-NEXT:    addss %xmm3, %xmm2
; SSE-NEXT:    addss %xmm2, %xmm0
; SSE-NEXT:    retq
;
; AVX-LABEL: reassociate_adds2:
; AVX:       # BB#0:
; AVX-NEXT:    vaddss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    vaddss %xmm3, %xmm2, %xmm1
; AVX-NEXT:    vaddss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    retq
  %t0 = fadd float %x0, %x1
  %t1 = fadd float %x2, %t0
  %t2 = fadd float %t1, %x3
  ret float %t2
}

define float @reassociate_adds3(float %x0, float %x1, float %x2, float %x3) {
; SSE-LABEL: reassociate_adds3:
; SSE:       # BB#0:
; SSE-NEXT:    addss %xmm1, %xmm0
; SSE-NEXT:    addss %xmm3, %xmm2
; SSE-NEXT:    addss %xmm2, %xmm0
; SSE-NEXT:    retq
;
; AVX-LABEL: reassociate_adds3:
; AVX:       # BB#0:
; AVX-NEXT:    vaddss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    vaddss %xmm3, %xmm2, %xmm1
; AVX-NEXT:    vaddss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    retq
  %t0 = fadd float %x0, %x1
  %t1 = fadd float %t0, %x2
  %t2 = fadd float %x3, %t1
  ret float %t2
}

define float @reassociate_adds4(float %x0, float %x1, float %x2, float %x3) {
; SSE-LABEL: reassociate_adds4:
; SSE:       # BB#0:
; SSE-NEXT:    addss %xmm1, %xmm0
; SSE-NEXT:    addss %xmm3, %xmm2
; SSE-NEXT:    addss %xmm2, %xmm0
; SSE-NEXT:    retq
;
; AVX-LABEL: reassociate_adds4:
; AVX:       # BB#0:
; AVX-NEXT:    vaddss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    vaddss %xmm3, %xmm2, %xmm1
; AVX-NEXT:    vaddss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    retq
  %t0 = fadd float %x0, %x1
  %t1 = fadd float %x2, %t0
  %t2 = fadd float %x3, %t1
  ret float %t2
}

; Verify that we reassociate some of these ops. The optimal balanced tree of adds is not
; produced because that would cost more compile time.

define float @reassociate_adds5(float %x0, float %x1, float %x2, float %x3, float %x4, float %x5, float %x6, float %x7) {
; SSE-LABEL: reassociate_adds5:
; SSE:       # BB#0:
; SSE-NEXT:    addss %xmm1, %xmm0
; SSE-NEXT:    addss %xmm3, %xmm2
; SSE-NEXT:    addss %xmm2, %xmm0
; SSE-NEXT:    addss %xmm5, %xmm4
; SSE-NEXT:    addss %xmm6, %xmm4
; SSE-NEXT:    addss %xmm4, %xmm0
; SSE-NEXT:    addss %xmm7, %xmm0
; SSE-NEXT:    retq
;
; AVX-LABEL: reassociate_adds5:
; AVX:       # BB#0:
; AVX-NEXT:    vaddss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    vaddss %xmm3, %xmm2, %xmm1
; AVX-NEXT:    vaddss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    vaddss %xmm5, %xmm4, %xmm1
; AVX-NEXT:    vaddss %xmm6, %xmm1, %xmm1
; AVX-NEXT:    vaddss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    vaddss %xmm7, %xmm0, %xmm0
; AVX-NEXT:    retq
  %t0 = fadd float %x0, %x1
  %t1 = fadd float %t0, %x2
  %t2 = fadd float %t1, %x3
  %t3 = fadd float %t2, %x4
  %t4 = fadd float %t3, %x5
  %t5 = fadd float %t4, %x6
  %t6 = fadd float %t5, %x7
  ret float %t6
}

; Verify that we only need two associative operations to reassociate the operands.
; Also, we should reassociate such that the result of the high latency division
; is used by the final 'add' rather than reassociating the %x3 operand with the
; division. The latter reassociation would not improve anything.

define float @reassociate_adds6(float %x0, float %x1, float %x2, float %x3) {
; SSE-LABEL: reassociate_adds6:
; SSE:       # BB#0:
; SSE-NEXT:    divss %xmm1, %xmm0
; SSE-NEXT:    addss %xmm3, %xmm2
; SSE-NEXT:    addss %xmm2, %xmm0
; SSE-NEXT:    retq
;
; AVX-LABEL: reassociate_adds6:
; AVX:       # BB#0:
; AVX-NEXT:    vdivss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    vaddss %xmm3, %xmm2, %xmm1
; AVX-NEXT:    vaddss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    retq
  %t0 = fdiv float %x0, %x1
  %t1 = fadd float %x2, %t0
  %t2 = fadd float %x3, %t1
  ret float %t2
}

; Verify that SSE and AVX scalar single-precison multiplies are reassociated.

define float @reassociate_muls1(float %x0, float %x1, float %x2, float %x3) {
; SSE-LABEL: reassociate_muls1:
; SSE:       # BB#0:
; SSE-NEXT:    divss %xmm1, %xmm0
; SSE-NEXT:    mulss %xmm3, %xmm2
; SSE-NEXT:    mulss %xmm2, %xmm0
; SSE-NEXT:    retq
;
; AVX-LABEL: reassociate_muls1:
; AVX:       # BB#0:
; AVX-NEXT:    vdivss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    vmulss %xmm3, %xmm2, %xmm1
; AVX-NEXT:    vmulss %xmm1, %xmm0, %xmm0
; AVX-NEXT:    retq
  %t0 = fdiv float %x0, %x1
  %t1 = fmul float %x2, %t0
  %t2 = fmul float %x3, %t1
  ret float %t2
}

; Verify that SSE and AVX scalar double-precison adds are reassociated.

define double @reassociate_adds_double(double %x0, double %x1, double %x2, double %x3) {
; SSE-LABEL: reassociate_adds_double:
; SSE:       # BB#0:
; SSE-NEXT:    divsd %xmm1, %xmm0
; SSE-NEXT:    addsd %xmm3, %xmm2
; SSE-NEXT:    addsd %xmm2, %xmm0
; SSE-NEXT:    retq
;
; AVX-LABEL: reassociate_adds_double:
; AVX:       # BB#0:
; AVX-NEXT:    vdivsd %xmm1, %xmm0, %xmm0
; AVX-NEXT:    vaddsd %xmm3, %xmm2, %xmm1
; AVX-NEXT:    vaddsd %xmm1, %xmm0, %xmm0
; AVX-NEXT:    retq
  %t0 = fdiv double %x0, %x1
  %t1 = fadd double %x2, %t0
  %t2 = fadd double %x3, %t1
  ret double %t2
}

; Verify that SSE and AVX scalar double-precison multiplies are reassociated.

define double @reassociate_muls_double(double %x0, double %x1, double %x2, double %x3) {
; SSE-LABEL: reassociate_muls_double:
; SSE:       # BB#0:
; SSE-NEXT:    divsd %xmm1, %xmm0
; SSE-NEXT:    mulsd %xmm3, %xmm2
; SSE-NEXT:    mulsd %xmm2, %xmm0
; SSE-NEXT:    retq
;
; AVX-LABEL: reassociate_muls_double:
; AVX:       # BB#0:
; AVX-NEXT:    vdivsd %xmm1, %xmm0, %xmm0
; AVX-NEXT:    vmulsd %xmm3, %xmm2, %xmm1
; AVX-NEXT:    vmulsd %xmm1, %xmm0, %xmm0
; AVX-NEXT:    retq
  %t0 = fdiv double %x0, %x1
  %t1 = fmul double %x2, %t0
  %t2 = fmul double %x3, %t1
  ret double %t2
}