1 ; RUN: llc < %s -march=x86-64 -mattr=+avx | FileCheck %s 2 ; 3 ; rdar:15221834 False AVX register dependencies cause 5x slowdown on 4 ; flops-6. Make sure the unused register read by vcvtsi2sdq is zeroed 5 ; to avoid cyclic dependence on a write to the same register in a 6 ; previous iteration. 7 8 ; CHECK-LABEL: t1: 9 ; CHECK-LABEL: %loop 10 ; CHECK: vxorps %[[REG:xmm.]], %{{xmm.}}, %{{xmm.}} 11 ; CHECK: vcvtsi2sdq %{{r[0-9a-x]+}}, %[[REG]], %{{xmm.}} 12 define i64 @t1(i64* nocapture %x, double* nocapture %y) nounwind { 13 entry: 14 %vx = load i64* %x 15 br label %loop 16 loop: 17 %i = phi i64 [ 1, %entry ], [ %inc, %loop ] 18 %s1 = phi i64 [ %vx, %entry ], [ %s2, %loop ] 19 %fi = sitofp i64 %i to double 20 %vy = load double* %y 21 %fipy = fadd double %fi, %vy 22 %iipy = fptosi double %fipy to i64 23 %s2 = add i64 %s1, %iipy 24 %inc = add nsw i64 %i, 1 25 %exitcond = icmp eq i64 %inc, 156250000 26 br i1 %exitcond, label %ret, label %loop 27 ret: 28 ret i64 %s2 29 } 30
