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AMDGPU: Eliminate half of i64 or if one operand is zero_extend from i32

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This helps clean up some of the mess when expanding unaligned 64-bit
loads when changed to be promote to v2i32, and fixes situations
where or x, 0 was emitted after splitting 64-bit ors during moveToVALU.

I think this could be a generic combine but I'm not sure.

llvm-svn: 266104
This commit is contained in:
Matt Arsenault 2016-04-12 18:24:38 +00:00
parent eb6088708e
commit 0740a1bead
2 changed files with 71 additions and 0 deletions
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30
lib/Target/AMDGPU/SIISelLowering.cpp
View File

@ -2332,6 +2332,36 @@ SDValue SITargetLowering::performOrCombine(SDNode *N,
SDValue LHS = N->getOperand(0);
SDValue RHS = N->getOperand(1);
EVT VT = N->getValueType(0);
if (VT == MVT::i64) {
// TODO: This could be a generic combine with a predicate for extracting the
// high half of an integer being free.
// (or i64:x, (zero_extend i32:y)) ->
// i64 (bitcast (v2i32 build_vector (or i32:y, lo_32(x)), hi_32(x)))
if (LHS.getOpcode() == ISD::ZERO_EXTEND &&
RHS.getOpcode() != ISD::ZERO_EXTEND)
std::swap(LHS, RHS);
if (RHS.getOpcode() == ISD::ZERO_EXTEND) {
SDValue ExtSrc = RHS.getOperand(0);
EVT SrcVT = ExtSrc.getValueType();
if (SrcVT == MVT::i32) {
SDLoc SL(N);
SDValue LowLHS, HiBits;
std::tie(LowLHS, HiBits) = split64BitValue(LHS, DAG);
SDValue LowOr = DAG.getNode(ISD::OR, SL, MVT::i32, LowLHS, ExtSrc);
DCI.AddToWorklist(LowOr.getNode());
DCI.AddToWorklist(HiBits.getNode());
SDValue Vec = DAG.getNode(ISD::BUILD_VECTOR, SL, MVT::v2i32,
LowOr, HiBits);
return DAG.getNode(ISD::BITCAST, SL, MVT::i64, Vec);
}
}
}
// or (fp_class x, c1), (fp_class x, c2) -> fp_class x, (c1 | c2)
if (LHS.getOpcode() == AMDGPUISD::FP_CLASS &&
RHS.getOpcode() == AMDGPUISD::FP_CLASS) {

41
test/CodeGen/AMDGPU/zext-i64-bit-operand.ll Normal file
View File

@ -0,0 +1,41 @@
; RUN: llc -march=amdgcn -verify-machineinstrs < %s | FileCheck -check-prefix=GCN %s
; GCN-LABEL: {{^}}zext_or_operand_i64:
; GCN: buffer_load_dwordx2 v{{\[}}[[LO:[0-9]+]]:[[HI:[0-9]+]]{{\]}}
; GCN: buffer_load_dword v[[LD32:[0-9]+]]
; GCN-NOT: _or_
; GCN-NOT: v[[HI]]
; GCN-NOT: v_mov_b32_e32 v{{[0-9]+}}, 0
; GCN: v_or_b32_e32 v[[LO]], v[[LD32]], v[[LO]]
; GCN-NOT: _or_
; GCN-NOT: v[[HI]]
; GCN-NOT: v_mov_b32_e32 v{{[0-9]+}}, 0
; GCN: buffer_store_dwordx2 v{{\[}}[[LO]]:[[HI]]{{\]}}
define void @zext_or_operand_i64(i64 addrspace(1)* %out, i64 addrspace(1)* %in0, i32 addrspace(1)* %in1) {
%ld.64 = load volatile i64, i64 addrspace(1)* %in0
%ld.32 = load volatile i32, i32 addrspace(1)* %in1
%ext = zext i32 %ld.32 to i64
%or = or i64 %ld.64, %ext
store i64 %or, i64 addrspace(1)* %out
ret void
}
; GCN-LABEL: {{^}}zext_or_operand_commute_i64:
; GCN: buffer_load_dwordx2 v{{\[}}[[LO:[0-9]+]]:[[HI:[0-9]+]]{{\]}}
; GCN: buffer_load_dword v[[LD32:[0-9]+]]
; GCN-NOT: _or_
; GCN-NOT: v[[HI]]
; GCN-NOT: v_mov_b32_e32 v{{[0-9]+}}, 0
; GCN: v_or_b32_e32 v[[LO]], v[[LD32]], v[[LO]]
; GCN-NOT: v[[HI]]
; GCN-NOT: _or_
; GCN-NOT: v_mov_b32_e32 v{{[0-9]+}}, 0
; GCN: buffer_store_dwordx2 v{{\[}}[[LO]]:[[HI]]{{\]}}
define void @zext_or_operand_commute_i64(i64 addrspace(1)* %out, i64 addrspace(1)* %in0, i32 addrspace(1)* %in1) {
%ld.64 = load volatile i64, i64 addrspace(1)* %in0
%ld.32 = load volatile i32, i32 addrspace(1)* %in1
%ext = zext i32 %ld.32 to i64
%or = or i64 %ext, %ld.64
store i64 %or, i64 addrspace(1)* %out
ret void
}