[GlobalISel]: Allow backends to custom legalize Intrinsics

https://reviews.llvm.org/D31359

Add a hook "legalizeInstrinsic" to allow backends to override this
and custom lower/legalize intrinsics.

llvm-svn: 364821

2 files changed, 10 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 88c9715e764..d62e786e091 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -82,6 +82,10 @@ LegalizerHelper::LegalizeResult
 LegalizerHelper::legalizeInstrStep(MachineInstr &MI) {
   LLVM_DEBUG(dbgs() << "Legalizing: "; MI.print(dbgs()));
 
+  if (MI.getOpcode() == TargetOpcode::G_INTRINSIC ||
+      MI.getOpcode() == TargetOpcode::G_INTRINSIC_W_SIDE_EFFECTS)
+    return LI.legalizeIntrinsic(MI, MRI, MIRBuilder) ? Legalized
+                                                     : UnableToLegalize;
   auto Step = LI.getAction(MI, MRI);
   switch (Step.Action) {
   case Legal:
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
index 14df53b9e84..6e1de95b327 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerInfo.cpp
@@ -658,6 +658,12 @@ LegalizerInfo::findVectorLegalAction(const InstrAspect &Aspect) const {
                       IntermediateType.getScalarSizeInBits())};
 }
 
+bool LegalizerInfo::legalizeIntrinsic(MachineInstr &MI,
+                                      MachineRegisterInfo &MRI,
+                                      MachineIRBuilder &MIRBuilder) const {
+  return true;
+}
+
 /// \pre Type indices of every opcode form a dense set starting from 0.
 void LegalizerInfo::verify(const MCInstrInfo &MII) const {
 #ifndef NDEBUG