1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
|
; 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
}
|
