[InstCombine] use m_APInt to allow icmp (add X, Y), C folds for splat constant vectors

This is a sibling of:
https://reviews.llvm.org/rL278859

llvm-svn: 278935

1 files changed, 29 insertions, 34 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 0a9f2787efb..b41662f1c11 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2198,53 +2198,48 @@ Instruction *InstCombiner::foldICmpSubConstant(ICmpInst &Cmp, Instruction *Sub,
 /// Fold icmp (add X, Y), C.
 Instruction *InstCombiner::foldICmpAddConstant(ICmpInst &Cmp, Instruction *Add,
                                                const APInt *C) {
-  // FIXME: This check restricts all folds under here to scalar types.
-  ConstantInt *RHS = dyn_cast<ConstantInt>(Cmp.getOperand(1));
-  if (!RHS)
-    return nullptr;
-
-  if (Cmp.isEquality())
+  Value *Y = Add->getOperand(1);
+  const APInt *C2;
+  if (Cmp.isEquality() || !match(Y, m_APInt(C2)))
     return nullptr;
 
-  // Fold: icmp pred (add X, C2), C
+  // Fold icmp pred (add X, C2), C.
   Value *X = Add->getOperand(0);
-  ConstantInt *AddC = dyn_cast<ConstantInt>(Add->getOperand(1));
-  if (!AddC)
-    return nullptr;
-
-  const APInt &C2 = AddC->getValue();
-  ConstantRange CR = Cmp.makeConstantRange(Cmp.getPredicate(), *C).subtract(C2);
+  Type *Ty = Add->getType();
+  auto CR = Cmp.makeConstantRange(Cmp.getPredicate(), *C).subtract(*C2);
   const APInt &Upper = CR.getUpper();
   const APInt &Lower = CR.getLower();
   if (Cmp.isSigned()) {
     if (Lower.isSignBit())
-      return new ICmpInst(ICmpInst::ICMP_SLT, X, Builder->getInt(Upper));
+      return new ICmpInst(ICmpInst::ICMP_SLT, X, ConstantInt::get(Ty, Upper));
     if (Upper.isSignBit())
-      return new ICmpInst(ICmpInst::ICMP_SGE, X, Builder->getInt(Lower));
+      return new ICmpInst(ICmpInst::ICMP_SGE, X, ConstantInt::get(Ty, Lower));
   } else {
     if (Lower.isMinValue())
-      return new ICmpInst(ICmpInst::ICMP_ULT, X, Builder->getInt(Upper));
+      return new ICmpInst(ICmpInst::ICMP_ULT, X, ConstantInt::get(Ty, Upper));
     if (Upper.isMinValue())
-      return new ICmpInst(ICmpInst::ICMP_UGE, X, Builder->getInt(Lower));
+      return new ICmpInst(ICmpInst::ICMP_UGE, X, ConstantInt::get(Ty, Lower));
   }
 
-  if (Add->hasOneUse()) {
-    // X+C <u C2 -> (X & -C2) == C
-    //   iff C & (C2-1) == 0
-    //       C2 is a power of 2
-    if (Cmp.getPredicate() == ICmpInst::ICMP_ULT && C->isPowerOf2() &&
-        (C2 & (*C - 1)) == 0)
-      return new ICmpInst(ICmpInst::ICMP_EQ, Builder->CreateAnd(X, -(*C)),
-                          ConstantExpr::getNeg(AddC));
-
-    // X+C >u C2 -> (X & ~C2) != C
-    //   iff C & C2 == 0
-    //       C2+1 is a power of 2
-    if (Cmp.getPredicate() == ICmpInst::ICMP_UGT && (*C + 1).isPowerOf2() &&
-        (C2 & *C) == 0)
-      return new ICmpInst(ICmpInst::ICMP_NE, Builder->CreateAnd(X, ~(*C)),
-                          ConstantExpr::getNeg(AddC));
-  }
+  if (!Add->hasOneUse())
+    return nullptr;
+
+  // X+C <u C2 -> (X & -C2) == C
+  //   iff C & (C2-1) == 0
+  //       C2 is a power of 2
+  if (Cmp.getPredicate() == ICmpInst::ICMP_ULT && C->isPowerOf2() &&
+      (*C2 & (*C - 1)) == 0)
+    return new ICmpInst(ICmpInst::ICMP_EQ, Builder->CreateAnd(X, -(*C)),
+                        ConstantExpr::getNeg(cast<Constant>(Y)));
+
+  // X+C >u C2 -> (X & ~C2) != C
+  //   iff C & C2 == 0
+  //       C2+1 is a power of 2
+  if (Cmp.getPredicate() == ICmpInst::ICMP_UGT && (*C + 1).isPowerOf2() &&
+      (*C2 & *C) == 0)
+    return new ICmpInst(ICmpInst::ICMP_NE, Builder->CreateAnd(X, ~(*C)),
+                        ConstantExpr::getNeg(cast<Constant>(Y)));
+
   return nullptr;
 }