Index: llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -4598,19 +4598,30 @@
   // The trunc masks high bits while the compare may effectively mask low bits.
   Value *X;
   const APInt *C;
-  if (match(Op0, m_OneUse(m_Trunc(m_Value(X)))) && match(Op1, m_Power2(C))) {
-    if (Pred == ICmpInst::ICMP_ULT) {
-      // (trunc X) u< Pow2C --> (X & MaskC) == 0
-      unsigned SrcBits = X->getType()->getScalarSizeInBits();
-      unsigned DstBits = Op0->getType()->getScalarSizeInBits();
-      APInt MaskC = APInt::getOneBitSet(SrcBits, DstBits) - C->zext(SrcBits);
+  if (!match(Op0, m_OneUse(m_Trunc(m_Value(X)))) || !match(Op1, m_APInt(C)))
+    return nullptr;
+
+  unsigned SrcBits = X->getType()->getScalarSizeInBits();
+  if (Pred == ICmpInst::ICMP_ULT) {
+    // If C is a power-of-2:
+    // (trunc X) u< C --> X & (~C + 1) == 0 (are all masked-high-bits clear?)
+    if (C->isPowerOf2()) {
+      Constant *MaskC = ConstantInt::get(X->getType(), (~*C + 1).zext(SrcBits));
       Value *And = Builder.CreateAnd(X, MaskC);
       Constant *Zero = ConstantInt::getNullValue(X->getType());
       return new ICmpInst(ICmpInst::ICMP_EQ, And, Zero);
     }
-    // TODO: Handle ugt.
+    // If C is a high-bit mask:
+    // (trunc X) u< C --> (X & C) != C (are any masked-high-bits clear?)
+    if ((~(*C)).isMask()) {
+      Constant *MaskC = ConstantInt::get(X->getType(), C->zext(SrcBits));
+      Value *And = Builder.CreateAnd(X, MaskC);
+      return new ICmpInst(ICmpInst::ICMP_NE, And, MaskC);
+    }
   }
 
+  // TODO: Handle ugt.
+
   return nullptr;
 }
 
Index: llvm/test/Transforms/InstCombine/icmp-trunc.ll
===================================================================
--- llvm/test/Transforms/InstCombine/icmp-trunc.ll
+++ llvm/test/Transforms/InstCombine/icmp-trunc.ll
@@ -71,8 +71,8 @@
 
 define i1 @ult_192(i32 %x) {
 ; CHECK-LABEL: @ult_192(
-; CHECK-NEXT:    [[T:%.*]] = trunc i32 [[X:%.*]] to i8
-; CHECK-NEXT:    [[R:%.*]] = icmp ult i8 [[T]], -64
+; CHECK-NEXT:    [[TMP1:%.*]] = and i32 [[X:%.*]], 192
+; CHECK-NEXT:    [[R:%.*]] = icmp ne i32 [[TMP1]], 192
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %t = trunc i32 %x to i8
@@ -82,8 +82,8 @@
 
 define <2 x i1> @ult_2044_splat(<2 x i16> %x) {
 ; CHECK-LABEL: @ult_2044_splat(
-; CHECK-NEXT:    [[T:%.*]] = trunc <2 x i16> [[X:%.*]] to <2 x i11>
-; CHECK-NEXT:    [[R:%.*]] = icmp ult <2 x i11> [[T]], <i11 -4, i11 -4>
+; CHECK-NEXT:    [[TMP1:%.*]] = and <2 x i16> [[X:%.*]], <i16 2044, i16 2044>
+; CHECK-NEXT:    [[R:%.*]] = icmp ne <2 x i16> [[TMP1]], <i16 2044, i16 2044>
 ; CHECK-NEXT:    ret <2 x i1> [[R]]
 ;
   %t = trunc <2 x i16> %x to <2 x i11>