[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

@@ -6347,57 +6347,51 @@ Instruction *InstCombinerImpl::foldICmpUsingKnownBits(ICmpInst &I) {
     case ICmpInst::ICMP_ULT: {
       if (Op1Min == Op0Max) // A <u B -> A != B if max(A) == min(B)
         return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
-      const APInt *CmpC;
-      if (match(Op1, m_APInt(CmpC))) {
-        // A <u C -> A == C-1 if min(A)+1 == C
-        if (*CmpC == Op0Min + 1)
-          return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
-                              ConstantInt::get(Op1->getType(), *CmpC - 1));
-        // X <u C --> X == 0, if the number of zero bits in the bottom of X
-        // exceeds the log2 of C.
-        if (Op0Known.countMinTrailingZeros() >= CmpC->ceilLogBase2())
-          return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
-                              Constant::getNullValue(Op1->getType()));
-      }
+      // A <u C -> A == C-1 if min(A)+1 == C
+      if (match(Op1, m_SpecificInt(Op0Min + 1)))
+        return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
+                            ConstantInt::get(Op1->getType(), Op0Min));
+      // X <u C --> X == 0, if the number of zero bits in the bottom of X
+      // exceeds the log2 of C.
+      if (match(Op1, m_CheckedInt([&Op0Known](const APInt &C) {
+                  return Op0Known.countMinTrailingZeros() >= C.ceilLogBase2();
+                })))
+        return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
+                            Constant::getNullValue(Op1->getType()));
       break;
     }
     case ICmpInst::ICMP_UGT: {
       if (Op1Max == Op0Min) // A >u B -> A != B if min(A) == max(B)
         return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
-      const APInt *CmpC;
-      if (match(Op1, m_APInt(CmpC))) {
-        // A >u C -> A == C+1 if max(a)-1 == C
-        if (*CmpC == Op0Max - 1)
-          return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
-                              ConstantInt::get(Op1->getType(), *CmpC + 1));
-        // X >u C --> X != 0, if the number of zero bits in the bottom of X
-        // exceeds the log2 of C.
-        if (Op0Known.countMinTrailingZeros() >= CmpC->getActiveBits())
-          return new ICmpInst(ICmpInst::ICMP_NE, Op0,
-                              Constant::getNullValue(Op1->getType()));
-      }
+      // A >u C -> A == C+1 if max(a)-1 == C
+      if (match(Op1, m_SpecificInt(Op0Max - 1)))
+        return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
+                            ConstantInt::get(Op1->getType(), Op0Max));
+      // X >u C --> X != 0, if the number of zero bits in the bottom of X
+      // exceeds the log2 of C.
+      if (match(Op1, m_CheckedInt([&Op0Known](const APInt &C) {
+                  return Op0Known.countMinTrailingZeros() >= C.getActiveBits();
+                })))
+        return new ICmpInst(ICmpInst::ICMP_NE, Op0,
+                            Constant::getNullValue(Op1->getType()));
       break;
     }
     case ICmpInst::ICMP_SLT: {
       if (Op1Min == Op0Max) // A <s B -> A != B if max(A) == min(B)
         return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
-      const APInt *CmpC;
-      if (match(Op1, m_APInt(CmpC))) {
-        if (*CmpC == Op0Min + 1) // A <s C -> A == C-1 if min(A)+1 == C
-          return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
-                              ConstantInt::get(Op1->getType(), *CmpC - 1));
-      }
+      // A <s C -> A == C-1 if min(A)+1 == C
+      if (match(Op1, m_SpecificInt(Op0Min + 1)))
+        return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
+                            ConstantInt::get(Op1->getType(), Op0Min));
       break;
     }
     case ICmpInst::ICMP_SGT: {
       if (Op1Max == Op0Min) // A >s B -> A != B if min(A) == max(B)
         return new ICmpInst(ICmpInst::ICMP_NE, Op0, Op1);
-      const APInt *CmpC;
-      if (match(Op1, m_APInt(CmpC))) {
-        if (*CmpC == Op0Max - 1) // A >s C -> A == C+1 if max(A)-1 == C
-          return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
-                              ConstantInt::get(Op1->getType(), *CmpC + 1));
-      }
+      // A >s C -> A == C+1 if max(A)-1 == C
+      if (match(Op1, m_SpecificInt(Op0Max - 1)))
+        return new ICmpInst(ICmpInst::ICMP_EQ, Op0,
+                            ConstantInt::get(Op1->getType(), Op0Max));
       break;
     }
     }

llvm/test/Transforms/InstCombine/signed-truncation-check.ll

@@ -212,10 +212,7 @@ define <3 x i1> @positive_vec_undef0(<3 x i32> %arg) {
 
 define <3 x i1> @positive_vec_undef1(<3 x i32> %arg) {
 ; CHECK-LABEL: @positive_vec_undef1(
-; CHECK-NEXT:    [[T1:%.*]] = icmp sgt <3 x i32> [[ARG:%.*]], <i32 -1, i32 -1, i32 -1>
-; CHECK-NEXT:    [[T2:%.*]] = add <3 x i32> [[ARG]], <i32 128, i32 undef, i32 128>
-; CHECK-NEXT:    [[T3:%.*]] = icmp ult <3 x i32> [[T2]], <i32 256, i32 256, i32 256>
-; CHECK-NEXT:    [[T4:%.*]] = and <3 x i1> [[T1]], [[T3]]
+; CHECK-NEXT:    [[T4:%.*]] = icmp ult <3 x i32> [[ARG:%.*]], <i32 128, i32 128, i32 128>
 ; CHECK-NEXT:    ret <3 x i1> [[T4]]
 ;
   %t1 = icmp sgt <3 x i32> %arg, <i32 -1, i32 -1, i32 -1>
@@ -227,10 +224,7 @@ define <3 x i1> @positive_vec_undef1(<3 x i32> %arg) {
 
 define <3 x i1> @positive_vec_undef2(<3 x i32> %arg) {
 ; CHECK-LABEL: @positive_vec_undef2(
-; CHECK-NEXT:    [[T1:%.*]] = icmp sgt <3 x i32> [[ARG:%.*]], <i32 -1, i32 -1, i32 -1>
-; CHECK-NEXT:    [[T2:%.*]] = add <3 x i32> [[ARG]], <i32 128, i32 128, i32 128>
-; CHECK-NEXT:    [[T3:%.*]] = icmp ult <3 x i32> [[T2]], <i32 256, i32 undef, i32 256>
-; CHECK-NEXT:    [[T4:%.*]] = and <3 x i1> [[T1]], [[T3]]
+; CHECK-NEXT:    [[T4:%.*]] = icmp ult <3 x i32> [[ARG:%.*]], <i32 128, i32 128, i32 128>
 ; CHECK-NEXT:    ret <3 x i1> [[T4]]
 ;
   %t1 = icmp sgt <3 x i32> %arg, <i32 -1, i32 -1, i32 -1>
@@ -242,10 +236,7 @@ define <3 x i1> @positive_vec_undef2(<3 x i32> %arg) {
 
 define <3 x i1> @positive_vec_undef3(<3 x i32> %arg) {
 ; CHECK-LABEL: @positive_vec_undef3(
-; CHECK-NEXT:    [[T1:%.*]] = icmp sgt <3 x i32> [[ARG:%.*]], <i32 -1, i32 undef, i32 -1>
-; CHECK-NEXT:    [[T2:%.*]] = add <3 x i32> [[ARG]], <i32 128, i32 undef, i32 128>
-; CHECK-NEXT:    [[T3:%.*]] = icmp ult <3 x i32> [[T2]], <i32 256, i32 256, i32 256>
-; CHECK-NEXT:    [[T4:%.*]] = and <3 x i1> [[T1]], [[T3]]
+; CHECK-NEXT:    [[T4:%.*]] = icmp ult <3 x i32> [[ARG:%.*]], <i32 128, i32 128, i32 128>
 ; CHECK-NEXT:    ret <3 x i1> [[T4]]
 ;
   %t1 = icmp sgt <3 x i32> %arg, <i32 -1, i32 undef, i32 -1>
@@ -257,10 +248,7 @@ define <3 x i1> @positive_vec_undef3(<3 x i32> %arg) {
 
 define <3 x i1> @positive_vec_undef4(<3 x i32> %arg) {
 ; CHECK-LABEL: @positive_vec_undef4(
-; CHECK-NEXT:    [[T1:%.*]] = icmp sgt <3 x i32> [[ARG:%.*]], <i32 -1, i32 undef, i32 -1>
-; CHECK-NEXT:    [[T2:%.*]] = add <3 x i32> [[ARG]], <i32 128, i32 128, i32 128>
-; CHECK-NEXT:    [[T3:%.*]] = icmp ult <3 x i32> [[T2]], <i32 256, i32 undef, i32 256>
-; CHECK-NEXT:    [[T4:%.*]] = and <3 x i1> [[T1]], [[T3]]
+; CHECK-NEXT:    [[T4:%.*]] = icmp ult <3 x i32> [[ARG:%.*]], <i32 128, i32 128, i32 128>
 ; CHECK-NEXT:    ret <3 x i1> [[T4]]
 ;
   %t1 = icmp sgt <3 x i32> %arg, <i32 -1, i32 undef, i32 -1>
@@ -272,10 +260,7 @@ define <3 x i1> @positive_vec_undef4(<3 x i32> %arg) {
 
 define <3 x i1> @positive_vec_undef5(<3 x i32> %arg) {
 ; CHECK-LABEL: @positive_vec_undef5(
-; CHECK-NEXT:    [[T1:%.*]] = icmp sgt <3 x i32> [[ARG:%.*]], <i32 -1, i32 -1, i32 -1>
-; CHECK-NEXT:    [[T2:%.*]] = add <3 x i32> [[ARG]], <i32 128, i32 undef, i32 128>
-; CHECK-NEXT:    [[T3:%.*]] = icmp ult <3 x i32> [[T2]], <i32 256, i32 undef, i32 256>
-; CHECK-NEXT:    [[T4:%.*]] = and <3 x i1> [[T1]], [[T3]]
+; CHECK-NEXT:    [[T4:%.*]] = icmp ult <3 x i32> [[ARG:%.*]], <i32 128, i32 128, i32 128>
 ; CHECK-NEXT:    ret <3 x i1> [[T4]]
 ;
   %t1 = icmp sgt <3 x i32> %arg, <i32 -1, i32 -1, i32 -1>
@@ -287,10 +272,7 @@ define <3 x i1> @positive_vec_undef5(<3 x i32> %arg) {
 
 define <3 x i1> @positive_vec_undef6(<3 x i32> %arg) {
 ; CHECK-LABEL: @positive_vec_undef6(
-; CHECK-NEXT:    [[T1:%.*]] = icmp sgt <3 x i32> [[ARG:%.*]], <i32 -1, i32 undef, i32 -1>
-; CHECK-NEXT:    [[T2:%.*]] = add <3 x i32> [[ARG]], <i32 128, i32 undef, i32 128>
-; CHECK-NEXT:    [[T3:%.*]] = icmp ult <3 x i32> [[T2]], <i32 256, i32 undef, i32 256>
-; CHECK-NEXT:    [[T4:%.*]] = and <3 x i1> [[T1]], [[T3]]
+; CHECK-NEXT:    [[T4:%.*]] = icmp ult <3 x i32> [[ARG:%.*]], <i32 128, i32 128, i32 128>
 ; CHECK-NEXT:    ret <3 x i1> [[T4]]
 ;
   %t1 = icmp sgt <3 x i32> %arg, <i32 -1, i32 undef, i32 -1>