llvm/test/CodeGen/ARM/softfp-fabs-fneg.ll
James Molloy 3504e2625a [ARM] Hoist fabs/fneg above a conversion to float.
This is especially visible in softfp mode, for example in the implementation of libm fabs/fneg functions. If we have:

%1 = vmovdrr r0, r1
%2 = fabs %1

then move the fabs before the vmovdrr:

%1 = and r1, #0x7FFFFFFF
%2 = vmovdrr r0, r1

This is never a lose, and could be a serious win because the vmovdrr may be followed by a vmovrrd, which would enable us to remove the conversion into FPRs completely.

We already do this for f32, but not for f64. Tests are added for both.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246360 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-29 10:49:11 +00:00

42 lines
1.1 KiB
LLVM

; RUN: llc -mtriple=armv7 < %s | FileCheck %s --check-prefix=CHECK-ARM --check-prefix=CHECK
; RUN: llc -mtriple=thumbv7 < %s | FileCheck %s --check-prefix=CHECK-THUMB --check-prefix=CHECK
target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
target triple = "armv7--"
define double @f(double %a) {
; CHECK-LABEL: f:
; CHECK: bfc r1, #31, #1
; CHECK-NEXT: bx lr
%x = call double @llvm.fabs.f64(double %a) readnone
ret double %x
}
define float @g(float %a) {
; CHECK-LABEL: g:
; CHECK-THUMB: bic r0, r0, #-2147483648
; CHECK-ARM: bfc r0, #31, #1
; CHECK-NEXT: bx lr
%x = call float @llvm.fabs.f32(float %a) readnone
ret float %x
}
define double @h(double %a) {
; CHECK-LABEL: h:
; CHECK: eor r1, r1, #-2147483648
; CHECK-NEXT: bx lr
%x = fsub nsz double -0.0, %a
ret double %x
}
define float @i(float %a) {
; CHECK-LABEL: i:
; CHECK: eor r0, r0, #-2147483648
; CHECK-NEXT: bx lr
%x = fsub nsz float -0.0, %a
ret float %x
}
declare double @llvm.fabs.f64(double) readnone
declare float @llvm.fabs.f32(float) readnone