[InnstCombine] Fix assertion failure on trivial cases

Author: dtcxzyw

llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

@@ -2239,7 +2239,7 @@ static Instruction *foldICmpShlLHSC(ICmpInst &Cmp, Instruction *Shl,
   unsigned TypeBits = C.getBitWidth();
   ICmpInst::Predicate Pred = Cmp.getPredicate();
   if (Cmp.isUnsigned()) {
-    assert(!C2->isZero() && C2->ult(C) &&
+    assert(!C2->isZero() && C2->ule(C) &&
            "Should be simplified by InstSimplify");
     APInt Div, Rem;
     APInt::udivrem(C, *C2, Div, Rem);

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

@@ -176,3 +176,13 @@ define i1 @fold_icmp_shl_nuw_c2_precondition2(i32 %x) {
   %cmp = icmp ult i32 %shl, 63
   ret i1 %cmp
 }
+
+; Make sure we don't crash on this case.
+define i1 @fold_icmp_shl_nuw_c2_precondition3(i32 %x) {
+; CHECK-LABEL: @fold_icmp_shl_nuw_c2_precondition3(
+; CHECK-NEXT:    ret i1 false
+;
+  %shl = shl nuw i32 1, %x
+  %cmp = icmp ult i32 %shl, 1
+  ret i1 %cmp
+}