diff --git a/llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp b/llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp
--- a/llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp
@@ -397,6 +397,10 @@
     uint64_t Shift = RHSKnown.getConstant().getZExtValue();
     LLVM_DEBUG(dbgs() << '[' << Depth << "] Shift is " << Shift << '\n');
 
+    // Guard against oversized shift amounts
+    if (Shift > MRI.getType(MI.getOperand(1).getReg()).getSizeInBits())
+      break;
+
     computeKnownBitsImpl(MI.getOperand(1).getReg(), Known, DemandedElts,
                          Depth + 1);
 
diff --git a/llvm/unittests/CodeGen/GlobalISel/KnownBitsTest.cpp b/llvm/unittests/CodeGen/GlobalISel/KnownBitsTest.cpp
--- a/llvm/unittests/CodeGen/GlobalISel/KnownBitsTest.cpp
+++ b/llvm/unittests/CodeGen/GlobalISel/KnownBitsTest.cpp
@@ -725,3 +725,26 @@
   EXPECT_EQ(0xffu, KnownUmax.Zero.getZExtValue());
   EXPECT_EQ(0xffffffffffffff00, KnownUmax.One.getZExtValue());
 }
+
+TEST_F(AArch64GISelMITest, TestInvalidQueries) {
+  StringRef MIRString = R"(
+   %src:_(s32) = COPY $w0
+   %thirty3:_(s32) = G_CONSTANT i32 33
+   %shift:_(s32) = G_SHL %src, %thirty3
+   %final_copy:_(s32) = COPY %shift
+)";
+  setUp(MIRString);
+  if (!TM)
+    return;
+
+  Register CopyReg = Copies[Copies.size() - 1];
+  MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
+  Register ShlRes = FinalCopy->getOperand(1).getReg();
+
+  GISelKnownBits Info(*MF);
+  KnownBits Res = Info.getKnownBits(ShlRes);
+
+  // We don't know what the result of the shift is, but we should not crash
+  EXPECT_TRUE(Res.One.isNullValue());
+  EXPECT_TRUE(Res.Zero.isNullValue());
+}
\ No newline at end of file