| ; RUN: llc < %s -march=x86-64 -mattr=+avx | FileCheck %s |
| ; |
| ; rdar:15221834 False AVX register dependencies cause 5x slowdown on |
| ; flops-6. Make sure the unused register read by vcvtsi2sdq is zeroed |
| ; to avoid cyclic dependence on a write to the same register in a |
| ; previous iteration. |
| |
| ; CHECK-LABEL: t1: |
| ; CHECK-LABEL: %loop |
| ; CHECK: vxorps %[[REG:xmm.]], %{{xmm.}}, %{{xmm.}} |
| ; CHECK: vcvtsi2sdq %{{r[0-9a-x]+}}, %[[REG]], %{{xmm.}} |
| define i64 @t1(i64* nocapture %x, double* nocapture %y) nounwind { |
| entry: |
| %vx = load i64* %x |
| br label %loop |
| loop: |
| %i = phi i64 [ 1, %entry ], [ %inc, %loop ] |
| %s1 = phi i64 [ %vx, %entry ], [ %s2, %loop ] |
| %fi = sitofp i64 %i to double |
| %vy = load double* %y |
| %fipy = fadd double %fi, %vy |
| %iipy = fptosi double %fipy to i64 |
| %s2 = add i64 %s1, %iipy |
| %inc = add nsw i64 %i, 1 |
| %exitcond = icmp eq i64 %inc, 156250000 |
| br i1 %exitcond, label %ret, label %loop |
| ret: |
| ret i64 %s2 |
| } |
