Add flags to indicate that there are "never" side effects or that there "may be"
side effects for machine instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45022 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/llvm/Target/TargetInstrInfo.h b/include/llvm/Target/TargetInstrInfo.h
index f463c8a..e617e69 100644
--- a/include/llvm/Target/TargetInstrInfo.h
+++ b/include/llvm/Target/TargetInstrInfo.h
@@ -91,6 +91,18 @@
// ARM instructions which can set condition code if 's' bit is set.
const unsigned M_HAS_OPTIONAL_DEF = 1 << 17;
+// M_MAY_HAVE_SIDE_EFFECTS - Set if this instruction *might* have side effects,
+// e.g. load instructions. Note: This and M_NEVER_HAS_SIDE_EFFECTS are mutually
+// exclusive. You can't set both! If neither flag is set, then the instruction
+// *always* has side effects.
+const unsigned M_MAY_HAVE_SIDE_EFFECTS = 1 << 18;
+
+// M_NEVER_HAS_SIDE_EFFECTS - Set if this instruction *never* has side effects,
+// e.g., xor on X86. Note: This and M_MAY_HAVE_SIDE_EFFECTS are mutually
+// exclusive. You can't set both! If neither flag is set, then the instruction
+// *always* has side effects.
+const unsigned M_NEVER_HAS_SIDE_EFFECTS = 1 << 19;
+
// Machine operand flags
// M_LOOK_UP_PTR_REG_CLASS - Set if this operand is a pointer value and it
// requires a callback to look up its register class.
diff --git a/lib/Target/Target.td b/lib/Target/Target.td
index 4c278bb..9619cb9 100644
--- a/lib/Target/Target.td
+++ b/lib/Target/Target.td
@@ -203,6 +203,11 @@
bit usesCustomDAGSchedInserter = 0; // Pseudo instr needing special help.
bit hasCtrlDep = 0; // Does this instruction r/w ctrl-flow chains?
bit isNotDuplicable = 0; // Is it unsafe to duplicate this instruction?
+
+ // Side effect flags - If neither of these flags is set, then the instruction
+ // *always* has side effects. Otherwise, it's one or the other.
+ bit mayHaveSideEffects = 0; // This instruction *may* have side effects.
+ bit neverHasSideEffects = 0; // This instruction never has side effects.
InstrItinClass Itinerary = NoItinerary;// Execution steps used for scheduling.
diff --git a/utils/TableGen/CodeGenInstruction.h b/utils/TableGen/CodeGenInstruction.h
index c209b13..8f1bf54 100644
--- a/utils/TableGen/CodeGenInstruction.h
+++ b/utils/TableGen/CodeGenInstruction.h
@@ -104,6 +104,8 @@
bool hasCtrlDep;
bool isNotDuplicable;
bool hasOptionalDef;
+ bool mayHaveSideEffects;
+ bool neverHasSideEffects;
/// ParseOperandName - Parse an operand name like "$foo" or "$foo.bar",
/// where $foo is a whole operand and $foo.bar refers to a suboperand.
diff --git a/utils/TableGen/CodeGenTarget.cpp b/utils/TableGen/CodeGenTarget.cpp
index 47bbecb..a2fe370 100644
--- a/utils/TableGen/CodeGenTarget.cpp
+++ b/utils/TableGen/CodeGenTarget.cpp
@@ -395,9 +395,15 @@
usesCustomDAGSchedInserter = R->getValueAsBit("usesCustomDAGSchedInserter");
hasCtrlDep = R->getValueAsBit("hasCtrlDep");
isNotDuplicable = R->getValueAsBit("isNotDuplicable");
+ mayHaveSideEffects = R->getValueAsBit("mayHaveSideEffects");
+ neverHasSideEffects = R->getValueAsBit("neverHasSideEffects");
hasOptionalDef = false;
hasVariableNumberOfOperands = false;
-
+
+ if (mayHaveSideEffects && neverHasSideEffects)
+ throw R->getName() +
+ ": cannot have both 'mayHaveSideEffects' and 'neverHasSideEffects' set!";
+
DagInit *DI;
try {
DI = R->getValueAsDag("OutOperandList");
diff --git a/utils/TableGen/InstrInfoEmitter.cpp b/utils/TableGen/InstrInfoEmitter.cpp
index 855a0f0..697a7e2 100644
--- a/utils/TableGen/InstrInfoEmitter.cpp
+++ b/utils/TableGen/InstrInfoEmitter.cpp
@@ -253,8 +253,9 @@
if (Inst.hasOptionalDef) OS << "|M_HAS_OPTIONAL_DEF";
if (Inst.usesCustomDAGSchedInserter)
OS << "|M_USES_CUSTOM_DAG_SCHED_INSERTION";
- if (Inst.hasVariableNumberOfOperands)
- OS << "|M_VARIABLE_OPS";
+ if (Inst.hasVariableNumberOfOperands) OS << "|M_VARIABLE_OPS";
+ if (Inst.mayHaveSideEffects) OS << "|M_MAY_HAVE_SIDE_EFFECTS";
+ if (Inst.neverHasSideEffects) OS << "|M_NEVER_HAS_SIDE_EFFECTS";
OS << ", 0";
// Emit all of the target-specific flags...