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In thumb2 mode, add pc is unpredictable. Use add + mov pc instead (that is until more optimization goes in).

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77364 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2009-07-28 20:53:24 +00:00
parent 6340632d3b
commit e7c329bf4b
6 changed files with 8 additions and 19 deletions
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9
lib/Target/ARM/ARMISelLowering.cpp
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@ -409,7 +409,6 @@ const char *ARMTargetLowering::getTargetNodeName(unsigned Opcode) const {
case ARMISD::tCALL: return "ARMISD::tCALL";
case ARMISD::BRCOND: return "ARMISD::BRCOND";
case ARMISD::BR_JT: return "ARMISD::BR_JT";
case ARMISD::BR2_JT: return "ARMISD::BR2_JT";
case ARMISD::RET_FLAG: return "ARMISD::RET_FLAG";
case ARMISD::PIC_ADD: return "ARMISD::PIC_ADD";
case ARMISD::CMP: return "ARMISD::CMP";
@ -1712,17 +1711,15 @@ SDValue ARMTargetLowering::LowerBR_JT(SDValue Op, SelectionDAG &DAG) {
SDValue UId = DAG.getConstant(AFI->createJumpTableUId(), PTy);
SDValue JTI = DAG.getTargetJumpTable(JT->getIndex(), PTy);
Table = DAG.getNode(ARMISD::WrapperJT, dl, MVT::i32, JTI, UId);
Index = DAG.getNode(ISD::MUL, dl, PTy, Index, DAG.getConstant(4, PTy));
SDValue Addr = DAG.getNode(ISD::ADD, dl, PTy, Index, Table);
if (Subtarget->isThumb2()) {
// Thumb2 uses a two-level jump. That is, it jumps into the jump table
// which does another jump to the destination. This also makes it easier
// to translate it to TBB / TBH later.
// FIXME: This might not work if the function is extremely large.
return DAG.getNode(ARMISD::BR2_JT, dl, MVT::Other, Chain, Table, Index,
JTI, UId);
return DAG.getNode(ARMISD::BR_JT, dl, MVT::Other, Chain, Addr, JTI, UId);
}
Index = DAG.getNode(ISD::MUL, dl, PTy, Index, DAG.getConstant(4, PTy));
SDValue Addr = DAG.getNode(ISD::ADD, dl, PTy, Index, Table);
if (getTargetMachine().getRelocationModel() == Reloc::PIC_) {
Addr = DAG.getLoad((MVT)MVT::i32, dl, Chain, Addr, NULL, 0);
Chain = Addr.getValue(1);

1
lib/Target/ARM/ARMISelLowering.h
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@ -40,7 +40,6 @@ namespace llvm {
tCALL, // Thumb function call.
BRCOND, // Conditional branch.
BR_JT, // Jumptable branch.
BR2_JT, // Jumptable branch (2 level - jumptable entry is a jump).
RET_FLAG, // Return with a flag operand.
PIC_ADD, // Add with a PC operand and a PIC label.

6
lib/Target/ARM/ARMInstrInfo.td
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@ -33,9 +33,6 @@ def SDT_ARMBrcond : SDTypeProfile<0, 2,
def SDT_ARMBrJT : SDTypeProfile<0, 3,
[SDTCisPtrTy<0>, SDTCisVT<1, i32>,
SDTCisVT<2, i32>]>;
def SDT_ARMBr2JT : SDTypeProfile<0, 4,
[SDTCisPtrTy<0>, SDTCisVT<1, i32>,
SDTCisVT<2, i32>, SDTCisVT<3, i32>]>;
def SDT_ARMCmp : SDTypeProfile<0, 2, [SDTCisSameAs<0, 1>]>;
@ -75,9 +72,6 @@ def ARMbrcond : SDNode<"ARMISD::BRCOND", SDT_ARMBrcond,
def ARMbrjt : SDNode<"ARMISD::BR_JT", SDT_ARMBrJT,
[SDNPHasChain]>;
def ARMbr2jt : SDNode<"ARMISD::BR2_JT", SDT_ARMBr2JT,
[SDNPHasChain]>;
def ARMcmp : SDNode<"ARMISD::CMP", SDT_ARMCmp,
[SDNPOutFlag]>;

2
lib/Target/ARM/ARMInstrThumb.td
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@ -198,7 +198,7 @@ let isBranch = 1, isTerminator = 1 in {
def tBR_JTr : T1JTI<(outs),
(ins tGPR:$target, jtblock_operand:$jt, i32imm:$id),
"mov pc, $target \n\t.align\t2\n$jt",
"mov pc, $target\n\t.align\t2\n$jt",
[(ARMbrjt tGPR:$target, tjumptable:$jt, imm:$id)]>;
}
}

7
lib/Target/ARM/ARMInstrThumb2.td
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@ -1050,10 +1050,9 @@ def t2B : T2XI<(outs), (ins brtarget:$target),
let isNotDuplicable = 1, isIndirectBranch = 1 in
def t2BR_JT :
T2JTI<(outs),
(ins GPR:$base, GPR:$idx, jt2block_operand:$jt, i32imm:$id),
"add.w pc, $base, $idx, lsl #2\n$jt",
[(ARMbr2jt GPR:$base, GPR:$idx, tjumptable:$jt, imm:$id)]>;
T2JTI<(outs), (ins GPR:$target, jt2block_operand:$jt, i32imm:$id),
"mov pc, $target\n$jt",
[(ARMbrjt GPR:$target, tjumptable:$jt, imm:$id)]>;
} // isBranch, isTerminator, isBarrier
// FIXME: should be able to write a pattern for ARMBrcond, but can't use

2
test/CodeGen/Thumb2/thumb2-jtbl.ll
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@ -4,7 +4,7 @@
define void @bar(i32 %n.u) {
entry:
; CHECK: bar:
; CHECK: add.w pc
; CHECK: mov pc
; CHECK: b.w LBB1_2
switch i32 %n.u, label %bb12 [i32 1, label %bb i32 2, label %bb6 i32 4, label %bb7 i32 5, label %bb8 i32 6, label %bb10 i32 7, label %bb1 i32 8, label %bb3 i32 9, label %bb4 i32 10, label %bb9 i32 11, label %bb2 i32 12, label %bb5 i32 13, label %bb11 ]