llvm-6502/test/CodeGen/R600/rsq.ll
Matt Arsenault 8603a3d1c5 R600: Implement getRsqrtEstimate
Only do for f32 since I'm unclear on both what this is expecting
for the refinement steps in terms of accuracy, and what
f64 instruction actually provides.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225827 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-13 20:53:18 +00:00

75 lines
2.9 KiB
LLVM

; RUN: llc -march=amdgcn -mcpu=SI -mattr=-fp32-denormals -verify-machineinstrs -enable-unsafe-fp-math < %s | FileCheck -check-prefix=SI-UNSAFE -check-prefix=SI %s
; RUN: llc -march=amdgcn -mcpu=SI -mattr=-fp32-denormals -verify-machineinstrs < %s | FileCheck -check-prefix=SI-SAFE -check-prefix=SI %s
declare i32 @llvm.r600.read.tidig.x() nounwind readnone
declare float @llvm.sqrt.f32(float) nounwind readnone
declare double @llvm.sqrt.f64(double) nounwind readnone
; SI-LABEL: {{^}}rsq_f32:
; SI: v_rsq_f32_e32
; SI: s_endpgm
define void @rsq_f32(float addrspace(1)* noalias %out, float addrspace(1)* noalias %in) nounwind {
%val = load float addrspace(1)* %in, align 4
%sqrt = call float @llvm.sqrt.f32(float %val) nounwind readnone
%div = fdiv float 1.0, %sqrt
store float %div, float addrspace(1)* %out, align 4
ret void
}
; SI-LABEL: {{^}}rsq_f64:
; SI-UNSAFE: v_rsq_f64_e32
; SI-SAFE: v_sqrt_f64_e32
; SI: s_endpgm
define void @rsq_f64(double addrspace(1)* noalias %out, double addrspace(1)* noalias %in) nounwind {
%val = load double addrspace(1)* %in, align 4
%sqrt = call double @llvm.sqrt.f64(double %val) nounwind readnone
%div = fdiv double 1.0, %sqrt
store double %div, double addrspace(1)* %out, align 4
ret void
}
; SI-LABEL: {{^}}rsq_f32_sgpr:
; SI: v_rsq_f32_e32 {{v[0-9]+}}, {{s[0-9]+}}
; SI: s_endpgm
define void @rsq_f32_sgpr(float addrspace(1)* noalias %out, float %val) nounwind {
%sqrt = call float @llvm.sqrt.f32(float %val) nounwind readnone
%div = fdiv float 1.0, %sqrt
store float %div, float addrspace(1)* %out, align 4
ret void
}
; Recognize that this is rsqrt(a) * rcp(b) * c,
; not 1 / ( 1 / sqrt(a)) * rcp(b) * c.
; SI-LABEL: @rsqrt_fmul
; SI-DAG: buffer_load_dword [[A:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64{{$}}
; SI-DAG: buffer_load_dword [[B:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:4
; SI-DAG: buffer_load_dword [[C:v[0-9]+]], {{v\[[0-9]+:[0-9]+\]}}, {{s\[[0-9]+:[0-9]+\]}}, 0 addr64 offset:8
; SI-UNSAFE-DAG: v_rsq_f32_e32 [[RSQA:v[0-9]+]], [[A]]
; SI-UNSAFE-DAG: v_rcp_f32_e32 [[RCPB:v[0-9]+]], [[B]]
; SI-UNSAFE-DAG: v_mul_f32_e32 [[TMP:v[0-9]+]], [[RCPB]], [[RSQA]]
; SI-UNSAFE: v_mul_f32_e32 [[RESULT:v[0-9]+]], [[TMP]], [[C]]
; SI-UNSAFE: buffer_store_dword [[RESULT]]
; SI-SAFE-NOT: v_rsq_f32
; SI: s_endpgm
define void @rsqrt_fmul(float addrspace(1)* %out, float addrspace(1)* %in) {
%tid = call i32 @llvm.r600.read.tidig.x() nounwind readnone
%out.gep = getelementptr float addrspace(1)* %out, i32 %tid
%gep.0 = getelementptr float addrspace(1)* %in, i32 %tid
%gep.1 = getelementptr float addrspace(1)* %gep.0, i32 1
%gep.2 = getelementptr float addrspace(1)* %gep.0, i32 2
%a = load float addrspace(1)* %gep.0
%b = load float addrspace(1)* %gep.1
%c = load float addrspace(1)* %gep.2
%x = call float @llvm.sqrt.f32(float %a)
%y = fmul float %x, %b
%z = fdiv float %c, %y
store float %z, float addrspace(1)* %out.gep
ret void
}