Index: llvm/include/llvm/CodeGen/GlobalISel/Utils.h
===================================================================
--- llvm/include/llvm/CodeGen/GlobalISel/Utils.h
+++ llvm/include/llvm/CodeGen/GlobalISel/Utils.h
@@ -408,17 +408,6 @@
                           const MachineRegisterInfo &MRI,
                           bool AllowUndef = false);
 
-/// Return true if the specified instruction is known to be a constant, or a
-/// vector of constants.
-///
-/// If \p AllowFP is true, this will consider G_FCONSTANT in addition to
-/// G_CONSTANT. If \p AllowOpaqueConstants is true, constant-like instructions
-/// such as G_GLOBAL_VALUE will also be considered.
-bool isConstantOrConstantVector(const MachineInstr &MI,
-                                const MachineRegisterInfo &MRI,
-                                bool AllowFP = true,
-                                bool AllowOpaqueConstants = true);
-
 /// Return true if the value is a constant 0 integer or a splatted vector of a
 /// constant 0 integer (with no undefs if \p AllowUndefs is false). This will
 /// handle G_BUILD_VECTOR and G_BUILD_VECTOR TRUNC as truncation is not an issue
@@ -454,10 +443,16 @@
 Optional<RegOrConstant> getVectorSplat(const MachineInstr &MI,
                                        const MachineRegisterInfo &MRI);
 
-/// Determines if \p MI defines a constant integer or a build vector of
-/// constant integers. Treats undef values as constants.
-bool isConstantOrConstantVector(MachineInstr &MI,
-                                const MachineRegisterInfo &MRI);
+/// Return true if the specified instruction is known to be a constant, or a
+/// vector of constants.
+///
+/// If \p AllowFP is true, this will consider G_FCONSTANT in addition to
+/// G_CONSTANT. If \p AllowOpaqueConstants is true, constant-like instructions
+/// such as G_GLOBAL_VALUE will also be considered.
+bool isConstantOrConstantVector(const MachineInstr &MI,
+                                const MachineRegisterInfo &MRI,
+                                bool AllowFP = true,
+                                bool AllowOpaqueConstants = true);
 
 /// Determines if \p MI defines a constant integer or a splat vector of
 /// constant integers.
Index: llvm/lib/CodeGen/GlobalISel/Utils.cpp
===================================================================
--- llvm/lib/CodeGen/GlobalISel/Utils.cpp
+++ llvm/lib/CodeGen/GlobalISel/Utils.cpp
@@ -1125,23 +1125,6 @@
   }
 }
 
-bool llvm::isConstantOrConstantVector(MachineInstr &MI,
-                                      const MachineRegisterInfo &MRI) {
-  Register Def = MI.getOperand(0).getReg();
-  if (auto C = getIConstantVRegValWithLookThrough(Def, MRI))
-    return true;
-  GBuildVector *BV = dyn_cast<GBuildVector>(&MI);
-  if (!BV)
-    return false;
-  for (unsigned SrcIdx = 0; SrcIdx < BV->getNumSources(); ++SrcIdx) {
-    if (getIConstantVRegValWithLookThrough(BV->getSourceReg(SrcIdx), MRI) ||
-        getOpcodeDef<GImplicitDef>(BV->getSourceReg(SrcIdx), MRI))
-      continue;
-    return false;
-  }
-  return true;
-}
-
 bool llvm::isConstantOrConstantVector(const MachineInstr &MI,
                                       const MachineRegisterInfo &MRI,
                                       bool AllowFP, bool AllowOpaqueConstants) {