ISelDAG: spot chain cycles involving MachineNodes
Previously, the DAGISel function WalkChainUsers was spotting that it
had entered already-selected territory by whether a node was a
MachineNode (amongst other things). Since it's fairly common practice
to insert MachineNodes during ISelLowering, this was not the correct
check.
Looking around, it seems that other nodes get their NodeId set to -1
upon selection, so this makes sure the same thing happens to all
MachineNodes and uses that characteristic to determine whether we
should stop looking for a loop during selection.
This should fix PR15840.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191165 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 6066f50..9b15c88 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -1857,15 +1857,15 @@
SDNode *User = *UI;
+ if (User->getOpcode() == ISD::HANDLENODE) // Root of the graph.
+ continue;
+
// If we see an already-selected machine node, then we've gone beyond the
// pattern that we're selecting down into the already selected chunk of the
// DAG.
- if (User->isMachineOpcode() ||
- User->getOpcode() == ISD::HANDLENODE) // Root of the graph.
- continue;
-
unsigned UserOpcode = User->getOpcode();
- if (UserOpcode == ISD::CopyToReg ||
+ if (User->isMachineOpcode() ||
+ UserOpcode == ISD::CopyToReg ||
UserOpcode == ISD::CopyFromReg ||
UserOpcode == ISD::INLINEASM ||
UserOpcode == ISD::EH_LABEL ||
diff --git a/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp b/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
index ee819e0..a865564 100644
--- a/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
+++ b/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
@@ -396,6 +396,7 @@
if (Node->isMachineOpcode()) {
DEBUG(dbgs() << "== "; Node->dump(CurDAG); dbgs() << "\n");
+ Node->setNodeId(-1);
return NULL;
}
diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index c2dbcb9..f6b3827 100644
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -2383,8 +2383,10 @@
SDNode *ARMDAGToDAGISel::Select(SDNode *N) {
SDLoc dl(N);
- if (N->isMachineOpcode())
+ if (N->isMachineOpcode()) {
+ N->setNodeId(-1);
return NULL; // Already selected.
+ }
switch (N->getOpcode()) {
default: break;
diff --git a/lib/Target/Hexagon/HexagonISelDAGToDAG.cpp b/lib/Target/Hexagon/HexagonISelDAGToDAG.cpp
index 9e78e51..5ae9328 100644
--- a/lib/Target/Hexagon/HexagonISelDAGToDAG.cpp
+++ b/lib/Target/Hexagon/HexagonISelDAGToDAG.cpp
@@ -1344,8 +1344,10 @@
SDNode *HexagonDAGToDAGISel::Select(SDNode *N) {
- if (N->isMachineOpcode())
+ if (N->isMachineOpcode()) {
+ N->setNodeId(-1);
return NULL; // Already selected.
+ }
switch (N->getOpcode()) {
diff --git a/lib/Target/MSP430/MSP430ISelDAGToDAG.cpp b/lib/Target/MSP430/MSP430ISelDAGToDAG.cpp
index 543f54c..4152829 100644
--- a/lib/Target/MSP430/MSP430ISelDAGToDAG.cpp
+++ b/lib/Target/MSP430/MSP430ISelDAGToDAG.cpp
@@ -395,6 +395,7 @@
DEBUG(errs() << "== ";
Node->dump(CurDAG);
errs() << "\n");
+ Node->setNodeId(-1);
return NULL;
}
diff --git a/lib/Target/Mips/MipsISelDAGToDAG.cpp b/lib/Target/Mips/MipsISelDAGToDAG.cpp
index 725d9b4..b428589 100644
--- a/lib/Target/Mips/MipsISelDAGToDAG.cpp
+++ b/lib/Target/Mips/MipsISelDAGToDAG.cpp
@@ -110,6 +110,7 @@
// If we have a custom node, we already have selected!
if (Node->isMachineOpcode()) {
DEBUG(errs() << "== "; Node->dump(CurDAG); errs() << "\n");
+ Node->setNodeId(-1);
return NULL;
}
diff --git a/lib/Target/NVPTX/NVPTXISelDAGToDAG.cpp b/lib/Target/NVPTX/NVPTXISelDAGToDAG.cpp
index 01fbdb3..68fa955 100644
--- a/lib/Target/NVPTX/NVPTXISelDAGToDAG.cpp
+++ b/lib/Target/NVPTX/NVPTXISelDAGToDAG.cpp
@@ -118,8 +118,10 @@
/// expanded, promoted and normal instructions.
SDNode *NVPTXDAGToDAGISel::Select(SDNode *N) {
- if (N->isMachineOpcode())
+ if (N->isMachineOpcode()) {
+ N->setNodeId(-1);
return NULL; // Already selected.
+ }
SDNode *ResNode = NULL;
switch (N->getOpcode()) {
diff --git a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 475bde1..6ba6af6 100644
--- a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -876,8 +876,10 @@
// target-specific node if it hasn't already been changed.
SDNode *PPCDAGToDAGISel::Select(SDNode *N) {
SDLoc dl(N);
- if (N->isMachineOpcode())
+ if (N->isMachineOpcode()) {
+ N->setNodeId(-1);
return NULL; // Already selected.
+ }
switch (N->getOpcode()) {
default: break;
diff --git a/lib/Target/R600/AMDGPUISelDAGToDAG.cpp b/lib/Target/R600/AMDGPUISelDAGToDAG.cpp
index a008c96..88b375b 100644
--- a/lib/Target/R600/AMDGPUISelDAGToDAG.cpp
+++ b/lib/Target/R600/AMDGPUISelDAGToDAG.cpp
@@ -195,6 +195,7 @@
SDNode *AMDGPUDAGToDAGISel::Select(SDNode *N) {
unsigned int Opc = N->getOpcode();
if (N->isMachineOpcode()) {
+ N->setNodeId(-1);
return NULL; // Already selected.
}
switch (Opc) {
diff --git a/lib/Target/Sparc/SparcISelDAGToDAG.cpp b/lib/Target/Sparc/SparcISelDAGToDAG.cpp
index e17a187..b012bfd 100644
--- a/lib/Target/Sparc/SparcISelDAGToDAG.cpp
+++ b/lib/Target/Sparc/SparcISelDAGToDAG.cpp
@@ -141,8 +141,10 @@
SDNode *SparcDAGToDAGISel::Select(SDNode *N) {
SDLoc dl(N);
- if (N->isMachineOpcode())
+ if (N->isMachineOpcode()) {
+ N->setNodeId(-1);
return NULL; // Already selected.
+ }
switch (N->getOpcode()) {
default: break;
diff --git a/lib/Target/SystemZ/SystemZISelDAGToDAG.cpp b/lib/Target/SystemZ/SystemZISelDAGToDAG.cpp
index 01f008a..d717408 100644
--- a/lib/Target/SystemZ/SystemZISelDAGToDAG.cpp
+++ b/lib/Target/SystemZ/SystemZISelDAGToDAG.cpp
@@ -999,6 +999,7 @@
// If we have a custom node, we already have selected!
if (Node->isMachineOpcode()) {
DEBUG(errs() << "== "; Node->dump(CurDAG); errs() << "\n");
+ Node->setNodeId(-1);
return 0;
}
diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index 32ad1aa..36d1690 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -2057,6 +2057,7 @@
if (Node->isMachineOpcode()) {
DEBUG(dbgs() << "== "; Node->dump(CurDAG); dbgs() << '\n');
+ Node->setNodeId(-1);
return NULL; // Already selected.
}
diff --git a/test/CodeGen/X86/2012-01-16-mfence-nosse-flags.ll b/test/CodeGen/X86/2012-01-16-mfence-nosse-flags.ll
index a883d79..cd8a16f 100644
--- a/test/CodeGen/X86/2012-01-16-mfence-nosse-flags.ll
+++ b/test/CodeGen/X86/2012-01-16-mfence-nosse-flags.ll
@@ -15,7 +15,7 @@
; CHECK: lock
; CHECK-NEXT: orl {{.*}}, (%esp)
-; CHECK-NEXT: cmpl $0
+; CHECK-NEXT: testl [[REG:%e[a-z]+]], [[REG]]
if.then: ; preds = %entry
tail call void bitcast (void (...)* @foo to void ()*)() nounwind
diff --git a/test/CodeGen/X86/i486-fence-loop.ll b/test/CodeGen/X86/i486-fence-loop.ll
new file mode 100644
index 0000000..d809619
--- /dev/null
+++ b/test/CodeGen/X86/i486-fence-loop.ll
@@ -0,0 +1,27 @@
+; RUN: llc -march=x86 -mcpu=i486 -o - %s | FileCheck %s
+
+; Main test here was that ISelDAG could cope with a MachineNode in the chain
+; from the first load to the "X86ISD::SUB". Previously it thought that meant no
+; cycle could be formed so it tried to use "sub (%eax), [[RHS]]".
+
+define void @gst_atomic_queue_push(i32* %addr) {
+; CHECK-LABEL: gst_atomic_queue_push:
+; CHECK: movl (%eax), [[LHS:%e[a-z]+]]
+; CHECK: lock
+; CHECK-NEXT: orl
+; CHECK: movl (%eax), [[RHS:%e[a-z]+]]
+; CHECK: cmpl [[LHS]], [[RHS]]
+
+entry:
+ br label %while.body
+
+while.body:
+ %0 = load volatile i32* %addr, align 4
+ fence seq_cst
+ %1 = load volatile i32* %addr, align 4
+ %cmp = icmp sgt i32 %1, %0
+ br i1 %cmp, label %while.body, label %if.then
+
+if.then:
+ ret void
+}
\ No newline at end of file