1 files changed, 78 insertions, 0 deletions
diff --git a/test/CodeGen/X86/fp-fast.ll b/test/CodeGen/X86/fp-fast.ll
index 27af5738ca3e8..4f503af716a80 100644
--- a/test/CodeGen/X86/fp-fast.ll
+++ b/test/CodeGen/X86/fp-fast.ll
@@ -114,3 +114,81 @@ define float @test11(float %a) {
   ret float %t2
 }
 
+; 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) {
+; CHECK-LABEL: reassociate_adds1:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    vaddss %xmm1, %xmm0, %xmm0
+; CHECK-NEXT:    vaddss %xmm3, %xmm2, %xmm1
+; CHECK-NEXT:    vaddss %xmm1, %xmm0, %xmm0
+; CHECK-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) {
+; CHECK-LABEL: reassociate_adds2:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    vaddss %xmm1, %xmm0, %xmm0
+; CHECK-NEXT:    vaddss %xmm3, %xmm2, %xmm1
+; CHECK-NEXT:    vaddss %xmm1, %xmm0, %xmm0
+; CHECK-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) {
+; CHECK-LABEL: reassociate_adds3:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    vaddss %xmm1, %xmm0, %xmm0
+; CHECK-NEXT:    vaddss %xmm3, %xmm2, %xmm1
+; CHECK-NEXT:    vaddss %xmm1, %xmm0, %xmm0
+; CHECK-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) {
+; CHECK-LABEL: reassociate_adds4:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    vaddss %xmm1, %xmm0, %xmm0
+; CHECK-NEXT:    vaddss %xmm3, %xmm2, %xmm1
+; CHECK-NEXT:    vaddss %xmm1, %xmm0, %xmm0
+; CHECK-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) {
+; CHECK-LABEL: reassociate_adds5:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    vaddss %xmm1, %xmm0, %xmm0
+; CHECK-NEXT:    vaddss %xmm3, %xmm2, %xmm1
+; CHECK-NEXT:    vaddss %xmm1, %xmm0, %xmm0
+; CHECK-NEXT:    vaddss %xmm5, %xmm4, %xmm1
+; CHECK-NEXT:    vaddss %xmm1, %xmm0, %xmm0
+; CHECK-NEXT:    vaddss %xmm7, %xmm6, %xmm1
+; CHECK-NEXT:    vaddss %xmm1, %xmm0, %xmm0
+; CHECK-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
+}