[GlobalISel] Translate calls to memcpy et al to G_INTRINSIC_W_SIDE_EFFECTs and legalize later.

I plan on adding memcpy optimizations in the GlobalISel pipeline, but we can't
do that unless we delay lowering to actual function calls. This patch changes
the translator to generate G_INTRINSIC_W_SIDE_EFFECTS for these functions, and
then have each target specify that using the new custom legalizer for intrinsics
hook that they want it expanded it a libcall.

Differential Revision: https://reviews.llvm.org/D64895

llvm-svn: 366516

3 files changed, 13 insertions, 2 deletions

diff --git a/llvm/include/llvm/CodeGen/GlobalISel/IRTranslator.h b/llvm/include/llvm/CodeGen/GlobalISel/IRTranslator.h
index 8654ba83f08..248578f10d7 100644
--- a/llvm/include/llvm/CodeGen/GlobalISel/IRTranslator.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/IRTranslator.h
@@ -213,8 +213,8 @@ private:
   bool translateStore(const User &U, MachineIRBuilder &MIRBuilder);
 
   /// Translate an LLVM string intrinsic (memcpy, memset, ...).
-  bool translateMemfunc(const CallInst &CI, MachineIRBuilder &MIRBuilder,
-                        unsigned ID);
+  bool translateMemFunc(const CallInst &CI, MachineIRBuilder &MIRBuilder,
+                        Intrinsic::ID ID);
 
   void getStackGuard(Register DstReg, MachineIRBuilder &MIRBuilder);
 
diff --git a/llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h b/llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h
index a0f21e8b19d..d2b9704599b 100644
--- a/llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h
@@ -236,6 +236,11 @@ createLibcall(MachineIRBuilder &MIRBuilder, RTLIB::Libcall Libcall,
               const CallLowering::ArgInfo &Result,
               ArrayRef<CallLowering::ArgInfo> Args);
 
+/// Create a libcall to memcpy et al.
+LegalizerHelper::LegalizeResult createMemLibcall(MachineIRBuilder &MIRBuilder,
+                                                 MachineRegisterInfo &MRI,
+                                                 MachineInstr &MI);
+
 } // End namespace llvm.
 
 #endif
diff --git a/llvm/include/llvm/CodeGen/MachineInstr.h b/llvm/include/llvm/CodeGen/MachineInstr.h
index c82c5b13750..eb8c496325d 100644
--- a/llvm/include/llvm/CodeGen/MachineInstr.h
+++ b/llvm/include/llvm/CodeGen/MachineInstr.h
@@ -1607,6 +1607,12 @@ public:
   /// to a register def in this instruction and point them to \p Reg instead.
   void changeDebugValuesDefReg(unsigned Reg);
 
+  /// Returns the Intrinsic::ID for this instruction.
+  /// \pre Must have an intrinsic ID operand.
+  unsigned getIntrinsicID() const {
+    return getOperand(getNumExplicitDefs()).getIntrinsicID();
+  }
+
 private:
   /// If this instruction is embedded into a MachineFunction, return the
   /// MachineRegisterInfo object for the current function, otherwise