diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -1555,17 +1555,23 @@
   // TODO: Handle any shifted constant by subtracting trailing zeros.
   // TODO: Handle non-equality predicates.
   Value *Y;
-  if (Cmp.isEquality() && match(X, m_Shl(m_One(), m_Value(Y)))) {
-    // (trunc (1 << Y) to iN) == 0 --> Y u>= N
-    // (trunc (1 << Y) to iN) != 0 --> Y u<  N
-    if (C.isZero()) {
-      auto NewPred = (Pred == Cmp.ICMP_EQ) ? Cmp.ICMP_UGE : Cmp.ICMP_ULT;
-      return new ICmpInst(NewPred, Y, ConstantInt::get(SrcTy, DstBits));
+  const APInt *C1;
+  if (Cmp.isEquality() && match(X, m_Shl(m_APIntAllowUndef(C1), m_Value(Y)))) {
+    if (C1->isPowerOf2()) {
+      // (trunc (2**C1 << Y) to iN) == 0 -> Y u>  N - C1 + 1
+      // (trunc (2**C1 << Y) to iN) != 0 -> Y u<= N - C1 + 1
+      if (C.isZero()) {
+        auto NewPred = (Pred == Cmp.ICMP_EQ) ? Cmp.ICMP_UGT : Cmp.ICMP_ULE;
+        return new ICmpInst(
+            NewPred, Y,
+            ConstantInt::get(SrcTy, C1->trunc(DstBits).countLeadingZeros()));
+      }
+      // (trunc (2**C1 << Y) to iN) == 2**C --> Y == C - C1
+      // (trunc (2**C1 << Y) to iN) != 2**C --> Y != C - C1
+      if (C.isPowerOf2() && C.uge(*C1))
+        return new ICmpInst(
+            Pred, Y, ConstantInt::get(SrcTy, C.logBase2() - C1->logBase2()));
     }
-    // (trunc (1 << Y) to iN) == 2**C --> Y == C
-    // (trunc (1 << Y) to iN) != 2**C --> Y != C
-    if (C.isPowerOf2())
-      return new ICmpInst(Pred, Y, ConstantInt::get(SrcTy, C.logBase2()));
   }
 
   if (Cmp.isEquality() && Trunc->hasOneUse()) {
diff --git a/llvm/test/Transforms/InstCombine/icmp-trunc.ll b/llvm/test/Transforms/InstCombine/icmp-trunc.ll
--- a/llvm/test/Transforms/InstCombine/icmp-trunc.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-trunc.ll
@@ -410,9 +410,7 @@
 
 define i1 @shl2_trunc_eq0(i9 %a) {
 ; CHECK-LABEL: @shl2_trunc_eq0(
-; CHECK-NEXT:    [[SHL:%.*]] = shl i9 2, [[A:%.*]]
-; CHECK-NEXT:    [[T:%.*]] = trunc i9 [[SHL]] to i6
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i6 [[T]], 0
+; CHECK-NEXT:    [[R:%.*]] = icmp ugt i9 [[A:%.*]], 4
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %shl = shl i9 2, %a
@@ -423,9 +421,7 @@
 
 define i1 @shl2_trunc_ne0(i9 %a) {
 ; CHECK-LABEL: @shl2_trunc_ne0(
-; CHECK-NEXT:    [[SHL:%.*]] = shl i9 2, [[A:%.*]]
-; CHECK-NEXT:    [[T:%.*]] = trunc i9 [[SHL]] to i6
-; CHECK-NEXT:    [[R:%.*]] = icmp ne i6 [[T]], 0
+; CHECK-NEXT:    [[R:%.*]] = icmp ult i9 [[A:%.*]], 5
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %shl = shl i9 2, %a
@@ -449,9 +445,7 @@
 
 define <2 x i1> @shl4_trunc_ne0(<2 x i8> %a) {
 ; CHECK-LABEL: @shl4_trunc_ne0(
-; CHECK-NEXT:    [[SHL:%.*]] = shl <2 x i8> <i8 4, i8 poison>, [[A:%.*]]
-; CHECK-NEXT:    [[T:%.*]] = trunc <2 x i8> [[SHL]] to <2 x i5>
-; CHECK-NEXT:    [[R:%.*]] = icmp ne <2 x i5> [[T]], zeroinitializer
+; CHECK-NEXT:    [[R:%.*]] = icmp ult <2 x i8> [[A:%.*]], <i8 3, i8 3>
 ; CHECK-NEXT:    ret <2 x i1> [[R]]
 ;
   %shl = shl <2 x i8> <i8 4, i8 poison>, %a
@@ -506,17 +500,9 @@
 }
 
 define i1 @shl2_trunc_eq8_i32(i32 %a) {
-; DL64-LABEL: @shl2_trunc_eq8_i32(
-; DL64-NEXT:    [[SHL:%.*]] = shl i32 2, [[A:%.*]]
-; DL64-NEXT:    [[TMP1:%.*]] = and i32 [[SHL]], 65534
-; DL64-NEXT:    [[R:%.*]] = icmp eq i32 [[TMP1]], 8
-; DL64-NEXT:    ret i1 [[R]]
-;
-; DL8-LABEL: @shl2_trunc_eq8_i32(
-; DL8-NEXT:    [[SHL:%.*]] = shl i32 2, [[A:%.*]]
-; DL8-NEXT:    [[T:%.*]] = trunc i32 [[SHL]] to i16
-; DL8-NEXT:    [[R:%.*]] = icmp eq i16 [[T]], 8
-; DL8-NEXT:    ret i1 [[R]]
+; CHECK-LABEL: @shl2_trunc_eq8_i32(
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i32 [[A:%.*]], 2
+; CHECK-NEXT:    ret i1 [[R]]
 ;
   %shl = shl i32 2, %a
   %t = trunc i32 %shl to i16
@@ -525,17 +511,9 @@
 }
 
 define i1 @shl2_trunc_ne8_i32(i32 %a) {
-; DL64-LABEL: @shl2_trunc_ne8_i32(
-; DL64-NEXT:    [[SHL:%.*]] = shl i32 2, [[A:%.*]]
-; DL64-NEXT:    [[TMP1:%.*]] = and i32 [[SHL]], 65534
-; DL64-NEXT:    [[R:%.*]] = icmp ne i32 [[TMP1]], 8
-; DL64-NEXT:    ret i1 [[R]]
-;
-; DL8-LABEL: @shl2_trunc_ne8_i32(
-; DL8-NEXT:    [[SHL:%.*]] = shl i32 2, [[A:%.*]]
-; DL8-NEXT:    [[T:%.*]] = trunc i32 [[SHL]] to i16
-; DL8-NEXT:    [[R:%.*]] = icmp ne i16 [[T]], 8
-; DL8-NEXT:    ret i1 [[R]]
+; CHECK-LABEL: @shl2_trunc_ne8_i32(
+; CHECK-NEXT:    [[R:%.*]] = icmp ne i32 [[A:%.*]], 2
+; CHECK-NEXT:    ret i1 [[R]]
 ;
   %shl = shl i32 2, %a
   %t = trunc i32 %shl to i16