[EraVM] Run MachineCopyPropagation Pass one more time

Run MCP one more time after pseudo expansion,
since we can produce copy like instructions
(e.g. from PTR_TO_INT) that can be optimized.
This patch implements isCopyInstrImpl target
hook which is called from MCP to detect copy
instructions after expansion from COPY is
performed.

Signed-off-by: Vladimir Radosavljevic <[email protected]>

Author: vladimirradosavljevic

llvm/lib/Target/EraVM/EraVMInstrInfo.cpp

@@ -732,6 +732,16 @@ EraVMCC::CondCodes EraVMInstrInfo::getCCCode(const MachineInstr &MI) const {
   return EraVMCC::COND_INVALID;
 }
 
+std::optional<DestSourcePair>
+EraVMInstrInfo::isCopyInstrImpl(const MachineInstr &MI) const {
+  if (MI.getOpcode() == EraVM::ADDrrr_s &&
+      MI.getOperand(2).getReg() == EraVM::R0 &&
+      getCCCode(MI) == EraVMCC::COND_NONE) {
+    return DestSourcePair{MI.getOperand(0), MI.getOperand(1)};
+  }
+  return std::nullopt;
+}
+
 /// Return whether outlining candidate ends with a tail call. This is true only
 /// if it is a terminator that ends function, call to outlined function that
 /// ends with a tail call, or call to a no return function.

llvm/lib/Target/EraVM/EraVMInstrInfo.h

@@ -406,6 +406,9 @@ class EraVMInstrInfo : public EraVMGenInstrInfo {
   // return true if the update is successful
   bool updateCCCode(MachineInstr &MI, EraVMCC::CondCodes CC) const;
 
+  std::optional<DestSourcePair>
+  isCopyInstrImpl(const MachineInstr &MI) const override;
+
   unsigned defaultOutlineReruns() const override { return 5; }
 
   bool shouldOutlineFromFunctionByDefault(MachineFunction &MF) const override;

llvm/lib/Target/EraVM/EraVMTargetMachine.cpp

@@ -319,6 +319,8 @@ void EraVMPassConfig::addPreSched2() {
 }
 
 void EraVMPassConfig::addPreEmitPass() {
+  if (getOptLevel() != CodeGenOpt::None)
+    addPass(createMachineCopyPropagationPass(true));
   addPass(createEraVMCombineAddressingModePass());
   addPass(createEraVMExpandSelectPass());
   addPass(createEraVMOptimizeSelectPostRAPass());

llvm/test/CodeGen/EraVM/O3-pipeline.ll

@@ -200,6 +200,7 @@ target triple = "eravm"
 ; CHECK-NEXT:       Branch Probability Basic Block Placement
 ; CHECK-NEXT:       Insert fentry calls
 ; CHECK-NEXT:       Insert XRay ops
+; CHECK-NEXT:       Machine Copy Propagation Pass
 ; CHECK-NEXT:       ReachingDefAnalysis
 ; CHECK-NEXT:       MachineDominator Tree Construction
 ; CHECK-NEXT:       EraVM combine instuctions to use complex addressing modes

llvm/test/CodeGen/EraVM/machine-cp.ll

@@ -7,8 +7,7 @@ target triple = "eravm"
 define i256 @test(i256 %dummy, ptr addrspace(3) %0) {
 ; CHECK-LABEL: test:
 ; CHECK:       ; %bb.0:
-; CHECK-NEXT:    add r2, r0, r1
-; CHECK-NEXT:    and 255, r1, r1
+; CHECK-NEXT:    and 255, r2, r1
 ; CHECK-NEXT:    ret
   %ptrtoint = ptrtoint ptr addrspace(3) %0 to i256
   %and = and i256 %ptrtoint, 255