Mark @llvm.trap cold

A call to @llvm.trap can be expected to be cold (i.e. unlikely to be
reached in a normal program execution).

Outlining paths which unconditionally trap is an important memory
saving. As the hot/cold splitting pass (imho) should not treat all
noreturn calls as cold, explicitly mark @llvm.trap cold so that it can
be outlined.

Split out of https://reviews.llvm.org/D54244.

Differential Revision: https://reviews.llvm.org/D54329

llvm-svn: 346885

3 files changed, 16 insertions, 1 deletions

diff --git a/llvm/utils/TableGen/CodeGenIntrinsics.h b/llvm/utils/TableGen/CodeGenIntrinsics.h
index 5d071595912..9487a79c143 100644
--- a/llvm/utils/TableGen/CodeGenIntrinsics.h
+++ b/llvm/utils/TableGen/CodeGenIntrinsics.h
@@ -124,6 +124,9 @@ struct CodeGenIntrinsic {
   /// True if the intrinsic is no-return.
   bool isNoReturn;
 
+  /// True if the intrinsic is cold.
+  bool isCold;
+
   /// True if the intrinsic is marked as convergent.
   bool isConvergent;
 
diff --git a/llvm/utils/TableGen/CodeGenTarget.cpp b/llvm/utils/TableGen/CodeGenTarget.cpp
index 305d2d19ff4..bcb65313555 100644
--- a/llvm/utils/TableGen/CodeGenTarget.cpp
+++ b/llvm/utils/TableGen/CodeGenTarget.cpp
@@ -536,6 +536,7 @@ CodeGenIntrinsic::CodeGenIntrinsic(Record *R) {
   isCommutative = false;
   canThrow = false;
   isNoReturn = false;
+  isCold = false;
   isNoDuplicate = false;
   isConvergent = false;
   isSpeculatable = false;
@@ -682,6 +683,8 @@ CodeGenIntrinsic::CodeGenIntrinsic(Record *R) {
       isConvergent = true;
     else if (Property->getName() == "IntrNoReturn")
       isNoReturn = true;
+    else if (Property->getName() == "IntrCold")
+      isCold = true;
     else if (Property->getName() == "IntrSpeculatable")
       isSpeculatable = true;
     else if (Property->getName() == "IntrHasSideEffects")
diff --git a/llvm/utils/TableGen/IntrinsicEmitter.cpp b/llvm/utils/TableGen/IntrinsicEmitter.cpp
index 06e44e3b57c..049282e5ebf 100644
--- a/llvm/utils/TableGen/IntrinsicEmitter.cpp
+++ b/llvm/utils/TableGen/IntrinsicEmitter.cpp
@@ -489,6 +489,9 @@ struct AttributeComparator {
     if (L->isNoReturn != R->isNoReturn)
       return R->isNoReturn;
 
+    if (L->isCold != R->isCold)
+      return R->isCold;
+
     if (L->isConvergent != R->isConvergent)
       return R->isConvergent;
 
@@ -622,7 +625,7 @@ void IntrinsicEmitter::EmitAttributes(const CodeGenIntrinsicTable &Ints,
 
     if (!intrinsic.canThrow ||
         intrinsic.ModRef != CodeGenIntrinsic::ReadWriteMem ||
-        intrinsic.isNoReturn || intrinsic.isNoDuplicate ||
+        intrinsic.isNoReturn || intrinsic.isCold || intrinsic.isNoDuplicate ||
         intrinsic.isConvergent || intrinsic.isSpeculatable) {
       OS << "      const Attribute::AttrKind Atts[] = {";
       bool addComma = false;
@@ -636,6 +639,12 @@ void IntrinsicEmitter::EmitAttributes(const CodeGenIntrinsicTable &Ints,
         OS << "Attribute::NoReturn";
         addComma = true;
       }
+      if (intrinsic.isCold) {
+        if (addComma)
+          OS << ",";
+        OS << "Attribute::Cold";
+        addComma = true;
+      }
       if (intrinsic.isNoDuplicate) {
         if (addComma)
           OS << ",";