[InstCombine] Add example usage for new Checked matcher API

There is no real motivation for this change other than to highlight a
case where the new `Checked` matcher API can handle non-splat-vecs
without increasing code complexity.

Author: goldsteinn

llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

@@ -7144,33 +7144,37 @@ Instruction *InstCombinerImpl::foldICmpCommutative(ICmpInst::Predicate Pred,
 
   // Folding (X / Y) pred X => X swap(pred) 0 for constant Y other than 0 or 1
   {
-    const APInt *Divisor;
-    if (match(Op0, m_UDiv(m_Specific(Op1), m_APInt(Divisor))) &&
-        Divisor->ugt(1)) {
+    if (match(Op0,
+              m_UDiv(m_Specific(Op1), m_CheckedInt([](const APInt &Divisor) {
+                       return Divisor.ugt(1);
+                     })))) {
       return new ICmpInst(ICmpInst::getSwappedPredicate(Pred), Op1,
                           Constant::getNullValue(Op1->getType()));
     }
 
     if (!ICmpInst::isUnsigned(Pred) &&
-        match(Op0, m_SDiv(m_Specific(Op1), m_APInt(Divisor))) &&
-        Divisor->ugt(1)) {
+        match(Op0,
+              m_SDiv(m_Specific(Op1), m_CheckedInt([](const APInt &Divisor) {
+                       return Divisor.ugt(1);
+                     })))) {
       return new ICmpInst(ICmpInst::getSwappedPredicate(Pred), Op1,
                           Constant::getNullValue(Op1->getType()));
     }
   }
 
   // Another case of this fold is (X >> Y) pred X => X swap(pred) 0 if Y != 0
   {
-    const APInt *Shift;
-    if (match(Op0, m_LShr(m_Specific(Op1), m_APInt(Shift))) &&
-        !Shift->isZero()) {
+    if (match(Op0, m_LShr(m_Specific(Op1), m_CheckedInt([](const APInt &Shift) {
+                            return !Shift.isZero();
+                          })))) {
       return new ICmpInst(ICmpInst::getSwappedPredicate(Pred), Op1,
                           Constant::getNullValue(Op1->getType()));
     }
 
     if ((Pred == CmpInst::ICMP_SLT || Pred == CmpInst::ICMP_SGE) &&
-        match(Op0, m_AShr(m_Specific(Op1), m_APInt(Shift))) &&
-        !Shift->isZero()) {
+        match(Op0, m_AShr(m_Specific(Op1), m_CheckedInt([](const APInt &Shift) {
+                            return !Shift.isZero();
+                          })))) {
       return new ICmpInst(ICmpInst::getSwappedPredicate(Pred), Op1,
                           Constant::getNullValue(Op1->getType()));
     }

llvm/test/Transforms/InstCombine/icmp-div-constant.ll

@@ -423,8 +423,7 @@ define <4 x i1> @lshr_by_const_cmp_sle_value(<4 x i32> %x) {
 
 define <4 x i1> @lshr_by_const_cmp_sle_value_non_splat(<4 x i32> %x) {
 ; CHECK-LABEL: @lshr_by_const_cmp_sle_value_non_splat(
-; CHECK-NEXT:    [[V:%.*]] = lshr <4 x i32> [[X:%.*]], <i32 3, i32 3, i32 3, i32 5>
-; CHECK-NEXT:    [[R:%.*]] = icmp sle <4 x i32> [[V]], [[X]]
+; CHECK-NEXT:    [[R:%.*]] = icmp sgt <4 x i32> [[X:%.*]], <i32 -1, i32 -1, i32 -1, i32 -1>
 ; CHECK-NEXT:    ret <4 x i1> [[R]]
 ;
   %v = lshr <4 x i32> %x, <i32 3, i32 3, i32 3, i32 5>