llvm-6502/test/CodeGen/ARM/fcopysign.ll
Evan Cheng c143dd4f63 Fix buggy fcopysign lowering.
This
define float @foo(float %x, float %y) nounwind readnone {
entry:
  %0 = tail call float @copysignf(float %x, float %y) nounwind readnone
  ret float %0
}

Was compiled to:
    vmov     s0, r1
    bic      r0, r0, #-2147483648
    vmov     s1, r0
    vcmpe.f32    s0, #0
    vmrs         apsr_nzcv, fpscr
    it           lt
    vneglt.f32   s1, s1
    vmov         r0, s1
    bx           lr

This fails to copy the sign of -0.0f because it's lost during the float to int
conversion. Also, it's sub-optimal when the inputs are in GPR registers.

Now it uses integer and + or operations when it's profitable. And it's correct!
    lsrs    r1, r1, #31
    bfi     r0, r1, #31, #1
    bx      lr
rdar://8984306


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125357 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-11 02:28:55 +00:00

46 lines
1.1 KiB
LLVM

; RUN: llc < %s -mtriple=armv7-apple-darwin -mcpu=cortex-a8 | FileCheck %s -check-prefix=SOFT
; RUN: llc < %s -mtriple=armv7-gnueabi -float-abi=hard -mcpu=cortex-a8 | FileCheck %s -check-prefix=HARD
; rdar://8984306
define float @test1(float %x, float %y) nounwind {
entry:
; SOFT: test1:
; SOFT: lsr r1, r1, #31
; SOFT: bfi r0, r1, #31, #1
; HARD: test1:
; HARD: vabs.f32 d0, d0
; HARD: cmp r0, #0
; HARD: vneglt.f32 s0, s0
%0 = tail call float @copysignf(float %x, float %y) nounwind
ret float %0
}
define double @test2(double %x, double %y) nounwind {
entry:
; SOFT: test2:
; SOFT: lsr r2, r3, #31
; SOFT: bfi r1, r2, #31, #1
; HARD: test2:
; HARD: vabs.f64 d0, d0
; HARD: cmp r1, #0
; HARD: vneglt.f64 d0, d0
%0 = tail call double @copysign(double %x, double %y) nounwind
ret double %0
}
define double @test3(double %x, double %y, double %z) nounwind {
entry:
; SOFT: test3:
; SOFT: vabs.f64
; SOFT: cmp {{.*}}, #0
; SOFT: vneglt.f64
%0 = fmul double %x, %y
%1 = tail call double @copysign(double %0, double %z) nounwind
ret double %1
}
declare double @copysign(double, double) nounwind
declare float @copysignf(float, float) nounwind