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Added single use check to ShrinkDemandedConstant 

Fixes cvt_f32_ubyte combine. performCvtF32UByteNCombine() could shrink
source node to demanded bits only even if there are other uses.

Differential Revision: https://reviews.llvm.org/D56289

llvm-svn: 350475
This commit is contained in:
Stanislav Mekhanoshin 2019-01-05 19:20:00 +00:00
parent 27406e1f9e
commit 35a3a3bd11
2 changed files with 23 additions and 0 deletions
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3
llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
View File

@ -350,6 +350,9 @@ bool TargetLowering::ShrinkDemandedConstant(SDValue Op, const APInt &Demanded,
SDLoc DL(Op);
unsigned Opcode = Op.getOpcode();
if (!Op.hasOneUse())
return false;
// Do target-specific constant optimization.
if (targetShrinkDemandedConstant(Op, Demanded, TLO))
return TLO.New.getNode();

20
llvm/test/CodeGen/AMDGPU/cvt_f32_ubyte.ll
View File

@ -281,3 +281,23 @@ define amdgpu_kernel void @extract_byte3_to_f32(float addrspace(1)* noalias %out
store float %cvt, float addrspace(1)* %out
ret void
}
; GCN-LABEL: {{^}}cvt_ubyte0_or_multiuse:
; GCN: {{buffer|flat}}_load_dword [[LOADREG:v[0-9]+]],
; GCN-DAG: v_or_b32_e32 [[OR:v[0-9]+]], 0x80000001, [[LOADREG]]
; GCN-DAG: v_cvt_f32_ubyte0_e32 [[CONV:v[0-9]+]], [[OR]]
; GCN: v_add_f32_e32 [[RES:v[0-9]+]], [[OR]], [[CONV]]
; GCN: buffer_store_dword [[RES]],
define amdgpu_kernel void @cvt_ubyte0_or_multiuse(i32 addrspace(1)* %in, float addrspace(1)* %out) {
bb:
%lid = tail call i32 @llvm.amdgcn.workitem.id.x()
%gep = getelementptr inbounds i32, i32 addrspace(1)* %in, i32 %lid
%load = load i32, i32 addrspace(1)* %gep
%or = or i32 %load, -2147483647
%and = and i32 %or, 255
%uitofp = uitofp i32 %and to float
%cast = bitcast i32 %or to float
%add = fadd float %cast, %uitofp
store float %add, float addrspace(1)* %out
ret void
}