[InstCombine] Address comments.

Author: dtcxzyw

llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

@@ -2239,8 +2239,8 @@ static Instruction *foldICmpShlLHSC(ICmpInst &Cmp, Instruction *Shl,
   unsigned TypeBits = C.getBitWidth();
   ICmpInst::Predicate Pred = Cmp.getPredicate();
   if (Cmp.isUnsigned()) {
-    assert(!C2->isZero() && C2->ule(C) &&
-           "Should be simplified by InstSimplify");
+    if (C2->isZero() || C2->ugt(C))
+      return nullptr;
     APInt Div, Rem;
     APInt::udivrem(C, *C2, Div, Rem);
     bool CIsPowerOf2 = Rem.isZero() && Div.isPowerOf2();

llvm/test/Transforms/InstCombine/icmp-shl-nuw.ll

@@ -144,8 +144,6 @@ define i1 @fold_icmp_shl_nuw_c3(i32 %x) {
   ret i1 %cmp
 }
 
-; Negative tests
-
 define i1 @fold_icmp_shl_nuw_c2_indivisible(i32 %x) {
 ; CHECK-LABEL: @fold_icmp_shl_nuw_c2_indivisible(
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp ult i32 [[X:%.*]], 2
@@ -156,6 +154,8 @@ define i1 @fold_icmp_shl_nuw_c2_indivisible(i32 %x) {
   ret i1 %cmp
 }
 
+; Negative tests
+
 define i1 @fold_icmp_shl_c2_without_nuw(i32 %x) {
 ; CHECK-LABEL: @fold_icmp_shl_c2_without_nuw(
 ; CHECK-NEXT:    [[SHL:%.*]] = shl i32 16, [[X:%.*]]