1 files changed, 52 insertions, 1 deletions
diff --git a/lib/CodeGen/GlobalISel/Utils.cpp b/lib/CodeGen/GlobalISel/Utils.cpp
index 1a5f88743d5f..59cbf93e7cd1 100644
--- a/lib/CodeGen/GlobalISel/Utils.cpp
+++ b/lib/CodeGen/GlobalISel/Utils.cpp
@@ -137,7 +137,7 @@ bool llvm::isTriviallyDead(const MachineInstr &MI,
   // If we can move an instruction, we can remove it.  Otherwise, it has
   // a side-effect of some sort.
   bool SawStore = false;
-  if (!MI.isSafeToMove(/*AA=*/nullptr, SawStore))
+  if (!MI.isSafeToMove(/*AA=*/nullptr, SawStore) && !MI.isPHI())
     return false;
 
   // Instructions without side-effects are dead iff they only define dead vregs.
@@ -235,6 +235,57 @@ APFloat llvm::getAPFloatFromSize(double Val, unsigned Size) {
   return APF;
 }
 
+Optional<APInt> llvm::ConstantFoldBinOp(unsigned Opcode, const unsigned Op1,
+                                        const unsigned Op2,
+                                        const MachineRegisterInfo &MRI) {
+  auto MaybeOp1Cst = getConstantVRegVal(Op1, MRI);
+  auto MaybeOp2Cst = getConstantVRegVal(Op2, MRI);
+  if (MaybeOp1Cst && MaybeOp2Cst) {
+    LLT Ty = MRI.getType(Op1);
+    APInt C1(Ty.getSizeInBits(), *MaybeOp1Cst, true);
+    APInt C2(Ty.getSizeInBits(), *MaybeOp2Cst, true);
+    switch (Opcode) {
+    default:
+      break;
+    case TargetOpcode::G_ADD:
+      return C1 + C2;
+    case TargetOpcode::G_AND:
+      return C1 & C2;
+    case TargetOpcode::G_ASHR:
+      return C1.ashr(C2);
+    case TargetOpcode::G_LSHR:
+      return C1.lshr(C2);
+    case TargetOpcode::G_MUL:
+      return C1 * C2;
+    case TargetOpcode::G_OR:
+      return C1 | C2;
+    case TargetOpcode::G_SHL:
+      return C1 << C2;
+    case TargetOpcode::G_SUB:
+      return C1 - C2;
+    case TargetOpcode::G_XOR:
+      return C1 ^ C2;
+    case TargetOpcode::G_UDIV:
+      if (!C2.getBoolValue())
+        break;
+      return C1.udiv(C2);
+    case TargetOpcode::G_SDIV:
+      if (!C2.getBoolValue())
+        break;
+      return C1.sdiv(C2);
+    case TargetOpcode::G_UREM:
+      if (!C2.getBoolValue())
+        break;
+      return C1.urem(C2);
+    case TargetOpcode::G_SREM:
+      if (!C2.getBoolValue())
+        break;
+      return C1.srem(C2);
+    }
+  }
+  return None;
+}
+
 void llvm::getSelectionDAGFallbackAnalysisUsage(AnalysisUsage &AU) {
   AU.addPreserved<StackProtector>();
 }