LLVM Bug Fix 13709: Remove needless lsr(Rp, #32) instruction access the
subreg_hireg of register pair Rp.
* lib/Target/Hexagon/HexagonPeephole.cpp(PeepholeDoubleRegsMap): New
DenseMap similar to PeepholeMap that additionally records subreg info
too.
(runOnMachineFunction): Record information in PeepholeDoubleRegsMap
and copy propagate the high sub-reg of Rp0 in Rp1 = lsr(Rp0, #32) to
the instruction Rx = COPY Rp1:logreg_subreg.
* test/CodeGen/Hexagon/remove_lsr.ll: New test.
llvm-svn: 163214
This commit is contained in:
Pranav Bhandarkar
parent
f6d2125829
commit
823f9ebaa3
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@ -109,6 +109,7 @@ bool HexagonPeephole::runOnMachineFunction(MachineFunction &MF) {
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MRI = &MF.getRegInfo();
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MRI = &MF.getRegInfo();
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DenseMap<unsigned, unsigned> PeepholeMap;
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DenseMap<unsigned, unsigned> PeepholeMap;
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DenseMap<unsigned, std::pair<unsigned, unsigned> > PeepholeDoubleRegsMap;
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if (DisableHexagonPeephole) return false;
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if (DisableHexagonPeephole) return false;
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@ -117,6 +118,7 @@ bool HexagonPeephole::runOnMachineFunction(MachineFunction &MF) {
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MBBb != MBBe; ++MBBb) {
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MBBb != MBBe; ++MBBb) {
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MachineBasicBlock* MBB = MBBb;
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MachineBasicBlock* MBB = MBBb;
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PeepholeMap.clear();
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PeepholeMap.clear();
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PeepholeDoubleRegsMap.clear();
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// Traverse the basic block.
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// Traverse the basic block.
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for (MachineBasicBlock::iterator MII = MBB->begin(); MII != MBB->end();
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for (MachineBasicBlock::iterator MII = MBB->begin(); MII != MBB->end();
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@ -140,6 +142,24 @@ bool HexagonPeephole::runOnMachineFunction(MachineFunction &MF) {
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}
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}
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}
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}
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// Look for this sequence below
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// %vregDoubleReg1 = LSRd_ri %vregDoubleReg0, 32
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// %vregIntReg = COPY %vregDoubleReg1:subreg_loreg.
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// and convert into
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// %vregIntReg = COPY %vregDoubleReg0:subreg_hireg.
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if (MI->getOpcode() == Hexagon::LSRd_ri) {
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assert(MI->getNumOperands() == 3);
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MachineOperand &Dst = MI->getOperand(0);
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MachineOperand &Src1 = MI->getOperand(1);
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MachineOperand &Src2 = MI->getOperand(2);
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if (Src2.getImm() != 32)
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continue;
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unsigned DstReg = Dst.getReg();
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unsigned SrcReg = Src1.getReg();
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PeepholeDoubleRegsMap[DstReg] =
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std::make_pair(*&SrcReg, 1/*Hexagon::subreg_hireg*/);
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}
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// Look for P=NOT(P).
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// Look for P=NOT(P).
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if (!DisablePNotP &&
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if (!DisablePNotP &&
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(MI->getOpcode() == Hexagon::NOT_p)) {
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(MI->getOpcode() == Hexagon::NOT_p)) {
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@ -178,6 +198,21 @@ bool HexagonPeephole::runOnMachineFunction(MachineFunction &MF) {
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// Change the 1st operand.
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// Change the 1st operand.
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MI->RemoveOperand(1);
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MI->RemoveOperand(1);
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MI->addOperand(MachineOperand::CreateReg(PeepholeSrc, false));
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MI->addOperand(MachineOperand::CreateReg(PeepholeSrc, false));
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} else {
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DenseMap<unsigned, std::pair<unsigned, unsigned> >::iterator DI =
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PeepholeDoubleRegsMap.find(SrcReg);
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if (DI != PeepholeDoubleRegsMap.end()) {
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std::pair<unsigned,unsigned> PeepholeSrc = DI->second;
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MI->RemoveOperand(1);
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MI->addOperand(MachineOperand::CreateReg(PeepholeSrc.first,
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false /*isDef*/,
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false /*isImp*/,
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false /*isKill*/,
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false /*isDead*/,
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false /*isUndef*/,
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false /*isEarlyClobber*/,
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PeepholeSrc.second));
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}
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}
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}
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}
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}
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}
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}
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@ -0,0 +1,80 @@
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; Test fix for PR-13709.
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; RUN: llc -march=hexagon -mcpu=hexagonv4 < %s | FileCheck %s
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; CHECK: foo
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; CHECK-NOT: lsr(r{{[0-9]+}}:{{[0-9]+}}, #32)
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; CHECK-NOT: lsr(r{{[0-9]+}}:{{[0-9]+}}, #32)
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; Convert the sequence
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; r17:16 = lsr(r11:10, #32)
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; .. = r16
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; into
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; r17:16 = lsr(r11:10, #32)
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; .. = r11
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; This makes the lsr instruction dead and it gets removed subsequently
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; by a dead code removal pass.
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%union.vect64 = type { i64 }
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%union.vect32 = type { i32 }
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define void @foo(%union.vect64* nocapture %sss_extracted_bit_rx_data_ptr,
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%union.vect32* nocapture %s_even, %union.vect32* nocapture %s_odd,
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i8* nocapture %scr_s_even_code_ptr, i8* nocapture %scr_s_odd_code_ptr)
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nounwind {
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entry:
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%scevgep = getelementptr %union.vect64* %sss_extracted_bit_rx_data_ptr, i32 1
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%scevgep28 = getelementptr %union.vect32* %s_odd, i32 1
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%scevgep32 = getelementptr %union.vect32* %s_even, i32 1
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%scevgep36 = getelementptr i8* %scr_s_odd_code_ptr, i32 1
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%scevgep39 = getelementptr i8* %scr_s_even_code_ptr, i32 1
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br label %for.body
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for.body: ; preds = %for.body, %entry
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%lsr.iv42 = phi i32 [ %lsr.iv.next, %for.body ], [ 2, %entry ]
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%lsr.iv40 = phi i8* [ %scevgep41, %for.body ], [ %scevgep39, %entry ]
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%lsr.iv37 = phi i8* [ %scevgep38, %for.body ], [ %scevgep36, %entry ]
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%lsr.iv33 = phi %union.vect32* [ %scevgep34, %for.body ], [ %scevgep32, %entry ]
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%lsr.iv29 = phi %union.vect32* [ %scevgep30, %for.body ], [ %scevgep28, %entry ]
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%lsr.iv = phi %union.vect64* [ %scevgep26, %for.body ], [ %scevgep, %entry ]
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%predicate_1.023 = phi i8 [ undef, %entry ], [ %10, %for.body ]
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%predicate.022 = phi i8 [ undef, %entry ], [ %9, %for.body ]
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%val.021 = phi i64 [ undef, %entry ], [ %srcval, %for.body ]
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%lsr.iv3335 = bitcast %union.vect32* %lsr.iv33 to i32*
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%lsr.iv2931 = bitcast %union.vect32* %lsr.iv29 to i32*
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%lsr.iv27 = bitcast %union.vect64* %lsr.iv to i64*
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%0 = tail call i64 @llvm.hexagon.A2.vsubhs(i64 0, i64 %val.021)
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%conv3 = sext i8 %predicate.022 to i32
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%1 = trunc i64 %val.021 to i32
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%2 = trunc i64 %0 to i32
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%3 = tail call i32 @llvm.hexagon.C2.mux(i32 %conv3, i32 %1, i32 %2)
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store i32 %3, i32* %lsr.iv3335, align 4, !tbaa !0
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%conv8 = sext i8 %predicate_1.023 to i32
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%4 = lshr i64 %val.021, 32
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%5 = trunc i64 %4 to i32
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%6 = lshr i64 %0, 32
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%7 = trunc i64 %6 to i32
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%8 = tail call i32 @llvm.hexagon.C2.mux(i32 %conv8, i32 %5, i32 %7)
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store i32 %8, i32* %lsr.iv2931, align 4, !tbaa !0
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%srcval = load i64* %lsr.iv27, align 8
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%9 = load i8* %lsr.iv40, align 1, !tbaa !1
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%10 = load i8* %lsr.iv37, align 1, !tbaa !1
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%lftr.wideiv = trunc i32 %lsr.iv42 to i8
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%exitcond = icmp eq i8 %lftr.wideiv, 32
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%scevgep26 = getelementptr %union.vect64* %lsr.iv, i32 1
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%scevgep30 = getelementptr %union.vect32* %lsr.iv29, i32 1
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%scevgep34 = getelementptr %union.vect32* %lsr.iv33, i32 1
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%scevgep38 = getelementptr i8* %lsr.iv37, i32 1
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%scevgep41 = getelementptr i8* %lsr.iv40, i32 1
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%lsr.iv.next = add i32 %lsr.iv42, 1
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br i1 %exitcond, label %for.end, label %for.body
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for.end: ; preds = %for.body
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ret void
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}
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declare i64 @llvm.hexagon.A2.vsubhs(i64, i64) nounwind readnone
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declare i32 @llvm.hexagon.C2.mux(i32, i32, i32) nounwind readnone
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!0 = metadata !{metadata !"long", metadata !1}
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!1 = metadata !{metadata !"omnipotent char", metadata !2}
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!2 = metadata !{metadata !"Simple C/C++ TBAA", null}
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