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-rw-r--r--lib/Target/X86/X86ISelLowering.cpp156
-rw-r--r--lib/Target/X86/X86ISelLowering.h7
-rw-r--r--test/CodeGen/X86/cmpxchg-i1.ll82
3 files changed, 188 insertions, 57 deletions
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index ecf718f639..171f832a44 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -3504,6 +3504,24 @@ static bool isX86CCUnsigned(unsigned X86CC) {
llvm_unreachable("covered switch fell through?!");
}
+/// Convert an integer condition code to an x86 one in the most straightforward
+/// way possible, with no optimisation attempt.
+static unsigned getSimpleX86IntCC(ISD::CondCode SetCCOpcode) {
+ switch (SetCCOpcode) {
+ default: llvm_unreachable("Invalid integer condition!");
+ case ISD::SETEQ: return X86::COND_E;
+ case ISD::SETGT: return X86::COND_G;
+ case ISD::SETGE: return X86::COND_GE;
+ case ISD::SETLT: return X86::COND_L;
+ case ISD::SETLE: return X86::COND_LE;
+ case ISD::SETNE: return X86::COND_NE;
+ case ISD::SETULT: return X86::COND_B;
+ case ISD::SETUGT: return X86::COND_A;
+ case ISD::SETULE: return X86::COND_BE;
+ case ISD::SETUGE: return X86::COND_AE;
+ }
+}
+
/// TranslateX86CC - do a one to one translation of a ISD::CondCode to the X86
/// specific condition code, returning the condition code and the LHS/RHS of the
/// comparison to make.
@@ -3527,19 +3545,7 @@ static unsigned TranslateX86CC(ISD::CondCode SetCCOpcode, bool isFP,
}
}
- switch (SetCCOpcode) {
- default: llvm_unreachable("Invalid integer condition!");
- case ISD::SETEQ: return X86::COND_E;
- case ISD::SETGT: return X86::COND_G;
- case ISD::SETGE: return X86::COND_GE;
- case ISD::SETLT: return X86::COND_L;
- case ISD::SETLE: return X86::COND_LE;
- case ISD::SETNE: return X86::COND_NE;
- case ISD::SETULT: return X86::COND_B;
- case ISD::SETUGT: return X86::COND_A;
- case ISD::SETULE: return X86::COND_BE;
- case ISD::SETUGE: return X86::COND_AE;
- }
+ return getSimpleX86IntCC(SetCCOpcode);
}
// First determine if it is required or is profitable to flip the operands.
@@ -10374,10 +10380,77 @@ SDValue X86TargetLowering::EmitTest(SDValue Op, unsigned X86CC, SDLoc dl,
return SDValue(New.getNode(), 1);
}
-/// Emit nodes that will be selected as "cmp Op0,Op1", or something
-/// equivalent.
-SDValue X86TargetLowering::EmitCmp(SDValue Op0, SDValue Op1, unsigned X86CC,
- SDLoc dl, SelectionDAG &DAG) const {
+static SDValue LowerCMP_SWAP(SDValue Op, const X86Subtarget *Subtarget,
+ SelectionDAG &DAG) {
+ MVT T = Op.getSimpleValueType();
+ SDLoc DL(Op);
+ unsigned Reg = 0;
+ unsigned size = 0;
+ switch(T.SimpleTy) {
+ default: llvm_unreachable("Invalid value type!");
+ case MVT::i8: Reg = X86::AL; size = 1; break;
+ case MVT::i16: Reg = X86::AX; size = 2; break;
+ case MVT::i32: Reg = X86::EAX; size = 4; break;
+ case MVT::i64:
+ assert(Subtarget->is64Bit() && "Node not type legal!");
+ Reg = X86::RAX; size = 8;
+ break;
+ }
+ SDValue cpIn = DAG.getCopyToReg(Op.getOperand(0), DL, Reg,
+ Op.getOperand(2), SDValue());
+ SDValue Ops[] = { cpIn.getValue(0),
+ Op.getOperand(1),
+ Op.getOperand(3),
+ DAG.getTargetConstant(size, MVT::i8),
+ cpIn.getValue(1) };
+ SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Glue);
+ MachineMemOperand *MMO = cast<AtomicSDNode>(Op)->getMemOperand();
+ SDValue Result = DAG.getMemIntrinsicNode(X86ISD::LCMPXCHG_DAG, DL, Tys,
+ Ops, T, MMO);
+ SDValue cpOut =
+ DAG.getCopyFromReg(Result.getValue(0), DL, Reg, T, Result.getValue(1));
+ return cpOut;
+}
+
+
+/// Emit nodes that will be selected as "cmp Op0,Op1", or something equivalent
+/// and set X86CC to the needed condition code to make use of the
+/// comparison. This may not be the obvious equivalent to CC if the comparison
+/// can be achieved more efficiently using a different method.
+SDValue X86TargetLowering::EmitCmp(SDValue Op0, SDValue Op1, ISD::CondCode CC,
+ SDLoc dl, SelectionDAG &DAG,
+ unsigned &X86CC) const {
+ // A cmpxchg instruction will actually perform the comparison
+ if ((Op0.getOpcode() == ISD::ATOMIC_CMP_SWAP && Op0.getOperand(2) == Op1) ||
+ (Op1.getOpcode() == ISD::ATOMIC_CMP_SWAP && Op1.getOperand(2) == Op0)) {
+ SDValue CmpSwap;
+ if (Op0.getOpcode() == ISD::ATOMIC_CMP_SWAP) {
+ // x86's cmpxchg instruction performs the equivalent of "cmp desired,
+ // loaded".
+ CmpSwap = Op0;
+ CC = getSetCCSwappedOperands(CC);
+ } else
+ CmpSwap = Op1;
+
+ // Lowering the CmpSwap node gives us a getCopyFromReg SDValue representing
+ // the value loaded. I.e. the ATOMIC_CMP_SWAP
+ X86CC = getSimpleX86IntCC(CC);
+ SDValue EFLAGS = LowerCMP_SWAP(CmpSwap, Subtarget, DAG);
+ DAG.ReplaceAllUsesOfValueWith(CmpSwap.getValue(0), EFLAGS);
+
+ // Glue on a copy from EFLAGS to be used in place of the required Cmp.
+ EFLAGS = DAG.getCopyFromReg(EFLAGS.getValue(1), dl, X86::EFLAGS,
+ MVT::i32, EFLAGS.getValue(2));
+ DAG.ReplaceAllUsesOfValueWith(CmpSwap.getValue(1), EFLAGS.getValue(1));
+
+ return EFLAGS;
+ }
+
+ bool IsFP = Op1.getSimpleValueType().isFloatingPoint();
+ X86CC = TranslateX86CC(CC, IsFP, Op0, Op1, DAG);
+ if (X86CC == X86::COND_INVALID)
+ return SDValue();
+
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op1)) {
if (C->getAPIntValue() == 0)
return EmitTest(Op0, X86CC, dl, DAG);
@@ -10385,7 +10458,7 @@ SDValue X86TargetLowering::EmitCmp(SDValue Op0, SDValue Op1, unsigned X86CC,
if (Op0.getValueType() == MVT::i1)
llvm_unreachable("Unexpected comparison operation for MVT::i1 operands");
}
-
+
if ((Op0.getValueType() == MVT::i8 || Op0.getValueType() == MVT::i16 ||
Op0.getValueType() == MVT::i32 || Op0.getValueType() == MVT::i64)) {
// Do the comparison at i32 if it's smaller, besides the Atom case.
@@ -10951,12 +11024,11 @@ SDValue X86TargetLowering::LowerSETCC(SDValue Op, SelectionDAG &DAG) const {
return DAG.getSetCC(dl, VT, Op0, DAG.getConstant(0, MVT::i1), NewCC);
}
- bool isFP = Op1.getSimpleValueType().isFloatingPoint();
- unsigned X86CC = TranslateX86CC(CC, isFP, Op0, Op1, DAG);
- if (X86CC == X86::COND_INVALID)
+ unsigned X86CC;
+ SDValue EFLAGS = EmitCmp(Op0, Op1, CC, dl, DAG, X86CC);
+ if (!EFLAGS.getNode())
return SDValue();
- SDValue EFLAGS = EmitCmp(Op0, Op1, X86CC, dl, DAG);
EFLAGS = ConvertCmpIfNecessary(EFLAGS, DAG);
SDValue SetCC = DAG.getNode(X86ISD::SETCC, dl, MVT::i8,
DAG.getConstant(X86CC, MVT::i8), EFLAGS);
@@ -11384,6 +11456,14 @@ SDValue X86TargetLowering::LowerBRCOND(SDValue Op, SelectionDAG &DAG) const {
if (isX86LogicalCmp(Cmp) || Opc == X86ISD::BT) {
Cond = Cmp;
addTest = false;
+ } else if (Opc == ISD::CopyFromReg &&
+ Cmp->getOperand(0)->getOpcode() == ISD::CopyFromReg &&
+ Cmp->getOperand(0)->getOperand(0)->getOpcode() ==
+ X86ISD::LCMPXCHG_DAG) {
+ assert(cast<RegisterSDNode>(Cmp->getOperand(1))->getReg() == X86::EFLAGS);
+ Chain = Cmp.getValue(1);
+ Cond = Cmp;
+ addTest = false;
} else {
switch (cast<ConstantSDNode>(CC)->getZExtValue()) {
default: break;
@@ -14363,38 +14443,6 @@ static SDValue LowerATOMIC_FENCE(SDValue Op, const X86Subtarget *Subtarget,
return DAG.getNode(X86ISD::MEMBARRIER, dl, MVT::Other, Op.getOperand(0));
}
-static SDValue LowerCMP_SWAP(SDValue Op, const X86Subtarget *Subtarget,
- SelectionDAG &DAG) {
- MVT T = Op.getSimpleValueType();
- SDLoc DL(Op);
- unsigned Reg = 0;
- unsigned size = 0;
- switch(T.SimpleTy) {
- default: llvm_unreachable("Invalid value type!");
- case MVT::i8: Reg = X86::AL; size = 1; break;
- case MVT::i16: Reg = X86::AX; size = 2; break;
- case MVT::i32: Reg = X86::EAX; size = 4; break;
- case MVT::i64:
- assert(Subtarget->is64Bit() && "Node not type legal!");
- Reg = X86::RAX; size = 8;
- break;
- }
- SDValue cpIn = DAG.getCopyToReg(Op.getOperand(0), DL, Reg,
- Op.getOperand(2), SDValue());
- SDValue Ops[] = { cpIn.getValue(0),
- Op.getOperand(1),
- Op.getOperand(3),
- DAG.getTargetConstant(size, MVT::i8),
- cpIn.getValue(1) };
- SDVTList Tys = DAG.getVTList(MVT::Other, MVT::Glue);
- MachineMemOperand *MMO = cast<AtomicSDNode>(Op)->getMemOperand();
- SDValue Result = DAG.getMemIntrinsicNode(X86ISD::LCMPXCHG_DAG, DL, Tys,
- Ops, T, MMO);
- SDValue cpOut =
- DAG.getCopyFromReg(Result.getValue(0), DL, Reg, T, Result.getValue(1));
- return cpOut;
-}
-
static SDValue LowerBITCAST(SDValue Op, const X86Subtarget *Subtarget,
SelectionDAG &DAG) {
MVT SrcVT = Op.getOperand(0).getSimpleValueType();
diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index af2e4344e5..2521446490 100644
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -1006,9 +1006,10 @@ namespace llvm {
SelectionDAG &DAG) const;
/// Emit nodes that will be selected as "cmp Op0,Op1", or something
- /// equivalent, for use with the given x86 condition code.
- SDValue EmitCmp(SDValue Op0, SDValue Op1, unsigned X86CC, SDLoc dl,
- SelectionDAG &DAG) const;
+ /// equivalent, possibly adjusting the condition code to a more appropriate
+ /// x86 form.
+ SDValue EmitCmp(SDValue Op0, SDValue Op1, ISD::CondCode CC, SDLoc dl,
+ SelectionDAG &DAG, unsigned &X86CC) const;
/// Convert a comparison if required by the subtarget.
SDValue ConvertCmpIfNecessary(SDValue Cmp, SelectionDAG &DAG) const;
diff --git a/test/CodeGen/X86/cmpxchg-i1.ll b/test/CodeGen/X86/cmpxchg-i1.ll
new file mode 100644
index 0000000000..53cf3e300f
--- /dev/null
+++ b/test/CodeGen/X86/cmpxchg-i1.ll
@@ -0,0 +1,82 @@
+; RUN: llc -mtriple=x86_64 -o - %s | FileCheck %s
+
+define i1 @try_cmpxchg(i32* %addr, i32 %desired, i32 %new) {
+; CHECK-LABEL: try_cmpxchg:
+; CHECK: cmpxchgl
+; CHECK-NOT: cmp
+; CHECK: sete %al
+; CHECK: retq
+ %old = cmpxchg i32* %addr, i32 %desired, i32 %new seq_cst seq_cst
+ %success = icmp eq i32 %old, %desired
+ ret i1 %success
+}
+
+define void @cmpxchg_flow(i64* %addr, i64 %desired, i64 %new) {
+; CHECK-LABEL: cmpxchg_flow:
+; CHECK: cmpxchgq
+; CHECK-NOT: cmp
+; CHECK-NOT: set
+; CHECK: {{jne|jeq}}
+ %old = cmpxchg i64* %addr, i64 %desired, i64 %new seq_cst seq_cst
+ %success = icmp eq i64 %old, %desired
+ br i1 %success, label %true, label %false
+
+true:
+ call void @foo()
+ ret void
+
+false:
+ call void @bar()
+ ret void
+}
+
+define i1 @cmpxchg_arithcmp(i16* %addr, i16 %desired, i16 %new) {
+; CHECK-LABEL: cmpxchg_arithcmp:
+; CHECK: cmpxchgw
+; CHECK-NOT: cmp
+; CHECK: setbe %al
+; CHECK: retq
+ %old = cmpxchg i16* %addr, i16 %desired, i16 %new seq_cst seq_cst
+ %success = icmp uge i16 %old, %desired
+ ret i1 %success
+}
+
+define i1 @cmpxchg_arithcmp_swapped(i8* %addr, i8 %desired, i8 %new) {
+; CHECK-LABEL: cmpxchg_arithcmp_swapped:
+; CHECK: cmpxchgb
+; CHECK-NOT: cmp
+; CHECK: setge %al
+; CHECK: retq
+ %old = cmpxchg i8* %addr, i8 %desired, i8 %new seq_cst seq_cst
+ %success = icmp sge i8 %desired, %old
+ ret i1 %success
+}
+
+define i64 @cmpxchg_sext(i32* %addr, i32 %desired, i32 %new) {
+; CHECK-LABEL: cmpxchg_sext:
+; CHECK-DAG: cmpxchgl
+; CHECK-DAG: movq $-1, %rax
+; CHECK-DAG: xorl %e[[ZERO:[a-z0-9]+]], %e[[ZERO]]
+; CHECK-NOT: cmpl
+; CHECK: cmovneq %r[[ZERO]], %rax
+; CHECK: retq
+ %old = cmpxchg i32* %addr, i32 %desired, i32 %new seq_cst seq_cst
+ %success = icmp eq i32 %old, %desired
+ %mask = sext i1 %success to i64
+ ret i64 %mask
+}
+
+define i32 @cmpxchg_zext(i32* %addr, i32 %desired, i32 %new) {
+; CHECK-LABEL: cmpxchg_zext:
+; CHECK: cmpxchgl
+; CHECK-NOT: cmp
+; CHECK: sete [[BYTE:%[a-z0-9]+]]
+; CHECK: movzbl [[BYTE]], %eax
+ %old = cmpxchg i32* %addr, i32 %desired, i32 %new seq_cst seq_cst
+ %success = icmp eq i32 %old, %desired
+ %mask = zext i1 %success to i32
+ ret i32 %mask
+}
+
+declare void @foo()
+declare void @bar()
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-25 09:59:32 +0000