Merge branch 'users/chapuni/cov/single/nextcount-base' into users/chapuni/cov/single/nextcountusers/chapuni/cov/single/nextcount

1 files changed, 14 insertions, 14 deletions

diff --git a/llvm/lib/CodeGen/ExpandMemCmp.cpp b/llvm/lib/CodeGen/ExpandMemCmp.cpp
index f8ca7e3..74f93e1 100644
--- a/llvm/lib/CodeGen/ExpandMemCmp.cpp
+++ b/llvm/lib/CodeGen/ExpandMemCmp.cpp
@@ -669,17 +669,25 @@ Value *MemCmpExpansion::getMemCmpOneBlock() {
   if (CI->hasOneUser()) {
     auto *UI = cast<Instruction>(*CI->user_begin());
     CmpPredicate Pred = ICmpInst::Predicate::BAD_ICMP_PREDICATE;
-    uint64_t Shift;
     bool NeedsZExt = false;
     // This is a special case because instead of checking if the result is less
     // than zero:
     //    bool result = memcmp(a, b, NBYTES) < 0;
     // Compiler is clever enough to generate the following code:
     //    bool result = memcmp(a, b, NBYTES) >> 31;
-    if (match(UI, m_LShr(m_Value(), m_ConstantInt(Shift))) &&
-        Shift == (CI->getType()->getIntegerBitWidth() - 1)) {
+    if (match(UI,
+              m_LShr(m_Value(),
+                     m_SpecificInt(CI->getType()->getIntegerBitWidth() - 1)))) {
       Pred = ICmpInst::ICMP_SLT;
       NeedsZExt = true;
+    } else if (match(UI, m_SpecificICmp(ICmpInst::ICMP_SGT, m_Specific(CI),
+                                        m_AllOnes()))) {
+      // Adjust predicate as if it compared with 0.
+      Pred = ICmpInst::ICMP_SGE;
+    } else if (match(UI, m_SpecificICmp(ICmpInst::ICMP_SLT, m_Specific(CI),
+                                        m_One()))) {
+      // Adjust predicate as if it compared with 0.
+      Pred = ICmpInst::ICMP_SLE;
     } else {
       // In case of a successful match this call will set `Pred` variable
       match(UI, m_ICmp(Pred, m_Specific(CI), m_Zero()));
@@ -696,17 +704,9 @@ Value *MemCmpExpansion::getMemCmpOneBlock() {
     }
   }
 
-  // The result of memcmp is negative, zero, or positive, so produce that by
-  // subtracting 2 extended compare bits: sub (ugt, ult).
-  // If a target prefers to use selects to get -1/0/1, they should be able
-  // to transform this later. The inverse transform (going from selects to math)
-  // may not be possible in the DAG because the selects got converted into
-  // branches before we got there.
-  Value *CmpUGT = Builder.CreateICmpUGT(Loads.Lhs, Loads.Rhs);
-  Value *CmpULT = Builder.CreateICmpULT(Loads.Lhs, Loads.Rhs);
-  Value *ZextUGT = Builder.CreateZExt(CmpUGT, Builder.getInt32Ty());
-  Value *ZextULT = Builder.CreateZExt(CmpULT, Builder.getInt32Ty());
-  return Builder.CreateSub(ZextUGT, ZextULT);
+  // The result of memcmp is negative, zero, or positive.
+  return Builder.CreateIntrinsic(Builder.getInt32Ty(), Intrinsic::ucmp,
+                                 {Loads.Lhs, Loads.Rhs});
 }
 
 // This function expands the memcmp call into an inline expansion and returns