[KnownBits] Move ValueTracking/SelectionDAG UREM KnownBits handling to KnownBits...

Both these have the same implementation - so move them to a single KnownBits copy.

GlobalISel will be able to use this as well with minimal effort.

diff --git a/llvm/include/llvm/Support/KnownBits.h b/llvm/include/llvm/Support/KnownBits.h
index 7ed20e1..2ef4a8f 100644 (file)
--- a/llvm/include/llvm/Support/KnownBits.h
+++ b/llvm/include/llvm/Support/KnownBits.h
@@ -261,6 +261,9 @@ public:
   /// Compute known bits for udiv(LHS, RHS).
   static KnownBits udiv(const KnownBits &LHS, const KnownBits &RHS);
 
+  /// Compute known bits for urem(LHS, RHS).
+  static KnownBits urem(const KnownBits &LHS, const KnownBits &RHS);
+
   /// Compute known bits for umax(LHS, RHS).
   static KnownBits umax(const KnownBits &LHS, const KnownBits &RHS);
 

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 07113e1..632a5ea 100644 (file)
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -1327,29 +1327,11 @@ static void computeKnownBitsFromOperator(const Operator *I,
       Known.makeNonNegative();
 
     break;
-  case Instruction::URem: {
-    if (ConstantInt *Rem = dyn_cast<ConstantInt>(I->getOperand(1))) {
-      const APInt &RA = Rem->getValue();
-      if (RA.isPowerOf2()) {
-        APInt LowBits = (RA - 1);
-        computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
-        Known.Zero |= ~LowBits;
-        Known.One &= LowBits;
-        break;
-      }
-    }
-
-    // Since the result is less than or equal to either operand, any leading
-    // zero bits in either operand must also exist in the result.
+  case Instruction::URem:
     computeKnownBits(I->getOperand(0), Known, Depth + 1, Q);
     computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
-
-    unsigned Leaders =
-        std::max(Known.countMinLeadingZeros(), Known2.countMinLeadingZeros());
-    Known.resetAll();
-    Known.Zero.setHighBits(Leaders);
+    Known = KnownBits::urem(Known, Known2);
     break;
-  }
   case Instruction::Alloca:
     Known.Zero.setLowBits(Log2(cast<AllocaInst>(I)->getAlign()));
     break;

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 6afddb5..782c38d 100644 (file)
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -3274,28 +3274,9 @@ KnownBits SelectionDAG::computeKnownBits(SDValue Op, const APInt &DemandedElts,
     }
     break;
   case ISD::UREM: {
-    if (ConstantSDNode *Rem = isConstOrConstSplat(Op.getOperand(1))) {
-      const APInt &RA = Rem->getAPIntValue();
-      if (RA.isPowerOf2()) {
-        APInt LowBits = (RA - 1);
-        Known2 = computeKnownBits(Op.getOperand(0), DemandedElts, Depth + 1);
-
-        // The upper bits are all zero, the lower ones are unchanged.
-        Known.Zero = Known2.Zero | ~LowBits;
-        Known.One = Known2.One & LowBits;
-        break;
-      }
-    }
-
-    // Since the result is less than or equal to either operand, any leading
-    // zero bits in either operand must also exist in the result.
     Known = computeKnownBits(Op.getOperand(0), DemandedElts, Depth + 1);
     Known2 = computeKnownBits(Op.getOperand(1), DemandedElts, Depth + 1);
-
-    uint32_t Leaders =
-        std::max(Known.countMinLeadingZeros(), Known2.countMinLeadingZeros());
-    Known.resetAll();
-    Known.Zero.setHighBits(Leaders);
+    Known = KnownBits::urem(Known, Known2);
     break;
   }
   case ISD::EXTRACT_ELEMENT: {

diff --git a/llvm/lib/Support/KnownBits.cpp b/llvm/lib/Support/KnownBits.cpp
index dff34eb..3a50938 100644 (file)
--- a/llvm/lib/Support/KnownBits.cpp
+++ b/llvm/lib/Support/KnownBits.cpp
@@ -324,6 +324,27 @@ KnownBits KnownBits::udiv(const KnownBits &LHS, const KnownBits &RHS) {
   return Known;
 }
 
+KnownBits KnownBits::urem(const KnownBits &LHS, const KnownBits &RHS) {
+  unsigned BitWidth = LHS.getBitWidth();
+  assert(!LHS.hasConflict() && !RHS.hasConflict());
+  KnownBits Known(BitWidth);
+
+  if (RHS.isConstant() && RHS.getConstant().isPowerOf2()) {
+    // The upper bits are all zero, the lower ones are unchanged.
+    APInt LowBits = RHS.getConstant() - 1;
+    Known.Zero = LHS.Zero | ~LowBits;
+    Known.One = LHS.One & LowBits;
+    return Known;
+  }
+
+  // Since the result is less than or equal to either operand, any leading
+  // zero bits in either operand must also exist in the result.
+  uint32_t Leaders =
+      std::max(LHS.countMinLeadingZeros(), RHS.countMinLeadingZeros());
+  Known.Zero.setHighBits(Leaders);
+  return Known;
+}
+
 KnownBits &KnownBits::operator&=(const KnownBits &RHS) {
   // Result bit is 0 if either operand bit is 0.
   Zero |= RHS.Zero;

diff --git a/llvm/unittests/Support/KnownBitsTest.cpp b/llvm/unittests/Support/KnownBitsTest.cpp
index 43e5981..60e61b5 100644 (file)
--- a/llvm/unittests/Support/KnownBitsTest.cpp
+++ b/llvm/unittests/Support/KnownBitsTest.cpp
@@ -114,6 +114,7 @@ TEST(KnownBitsTest, BinaryExhaustive) {
       KnownBits KnownSMin(KnownAnd);
       KnownBits KnownMul(KnownAnd);
       KnownBits KnownUDiv(KnownAnd);
+      KnownBits KnownURem(KnownAnd);
       KnownBits KnownShl(KnownAnd);
       KnownBits KnownLShr(KnownAnd);
       KnownBits KnownAShr(KnownAnd);
@@ -158,6 +159,10 @@ TEST(KnownBitsTest, BinaryExhaustive) {
             Res = N1.udiv(N2);
             KnownUDiv.One &= Res;
             KnownUDiv.Zero &= ~Res;
+
+            Res = N1.urem(N2);
+            KnownURem.One &= Res;
+            KnownURem.Zero &= ~Res;
           }
 
           if (N2.ult(1ULL << N1.getBitWidth())) {
@@ -218,6 +223,10 @@ TEST(KnownBitsTest, BinaryExhaustive) {
       EXPECT_TRUE(ComputedUDiv.Zero.isSubsetOf(KnownUDiv.Zero));
       EXPECT_TRUE(ComputedUDiv.One.isSubsetOf(KnownUDiv.One));
 
+      KnownBits ComputedURem = KnownBits::urem(Known1, Known2);
+      EXPECT_TRUE(ComputedURem.Zero.isSubsetOf(KnownURem.Zero));
+      EXPECT_TRUE(ComputedURem.One.isSubsetOf(KnownURem.One));
+
       KnownBits ComputedShl = KnownBits::shl(Known1, Known2);
       EXPECT_TRUE(ComputedShl.Zero.isSubsetOf(KnownShl.Zero));
       EXPECT_TRUE(ComputedShl.One.isSubsetOf(KnownShl.One));