2 files changed, 30 insertions, 23 deletions

diff --git a/compiler/dex/quick/mir_to_lir.h b/compiler/dex/quick/mir_to_lir.h
index a07274f17e..4fdc7289bf 100644
--- a/compiler/dex/quick/mir_to_lir.h
+++ b/compiler/dex/quick/mir_to_lir.h
@@ -1467,26 +1467,6 @@ class Mir2Lir {
       return InexpensiveConstantInt(value);
     }
 
-    /**
-     * @brief Whether division by the given divisor can be converted to multiply by its reciprocal.
-     * @param divisor A constant divisor bits of float type.
-     * @return Returns true iff, x/divisor == x*(1.0f/divisor), for every float x.
-     */
-    bool CanDivideByReciprocalMultiplyFloat(int32_t divisor) {
-      // True, if float value significand bits are 0.
-      return ((divisor & 0x7fffff) == 0);
-    }
-
-    /**
-     * @brief Whether division by the given divisor can be converted to multiply by its reciprocal.
-     * @param divisor A constant divisor bits of double type.
-     * @return Returns true iff, x/divisor == x*(1.0/divisor), for every double x.
-     */
-    bool CanDivideByReciprocalMultiplyDouble(int64_t divisor) {
-      // True, if double value significand bits are 0.
-      return ((divisor & ((UINT64_C(1) << 52) - 1)) == 0);
-    }
-
     // May be optimized by targets.
     virtual void GenMonitorEnter(int opt_flags, RegLocation rl_src);
     virtual void GenMonitorExit(int opt_flags, RegLocation rl_src);
diff --git a/compiler/optimizing/instruction_simplifier.cc b/compiler/optimizing/instruction_simplifier.cc
index 2df7c166d8..e79d4f4bdc 100644
--- a/compiler/optimizing/instruction_simplifier.cc
+++ b/compiler/optimizing/instruction_simplifier.cc
@@ -377,15 +377,42 @@ void InstructionSimplifierVisitor::VisitDiv(HDiv* instruction) {
     return;
   }
 
-  if ((input_cst != nullptr) && input_cst->IsMinusOne() &&
-      (Primitive::IsFloatingPointType(type) || Primitive::IsIntOrLongType(type))) {
+  if ((input_cst != nullptr) && input_cst->IsMinusOne()) {
     // Replace code looking like
     //    DIV dst, src, -1
     // with
     //    NEG dst, src
     instruction->GetBlock()->ReplaceAndRemoveInstructionWith(
-        instruction, (new (GetGraph()->GetArena()) HNeg(type, input_other)));
+        instruction, new (GetGraph()->GetArena()) HNeg(type, input_other));
     RecordSimplification();
+    return;
+  }
+
+  if ((input_cst != nullptr) && Primitive::IsFloatingPointType(type)) {
+    // Try replacing code looking like
+    //    DIV dst, src, constant
+    // with
+    //    MUL dst, src, 1 / constant
+    HConstant* reciprocal = nullptr;
+    if (type == Primitive::Primitive::kPrimDouble) {
+      double value = input_cst->AsDoubleConstant()->GetValue();
+      if (CanDivideByReciprocalMultiplyDouble(bit_cast<int64_t, double>(value))) {
+        reciprocal = GetGraph()->GetDoubleConstant(1.0 / value);
+      }
+    } else {
+      DCHECK_EQ(type, Primitive::kPrimFloat);
+      float value = input_cst->AsFloatConstant()->GetValue();
+      if (CanDivideByReciprocalMultiplyFloat(bit_cast<int32_t, float>(value))) {
+        reciprocal = GetGraph()->GetFloatConstant(1.0f / value);
+      }
+    }
+
+    if (reciprocal != nullptr) {
+      instruction->GetBlock()->ReplaceAndRemoveInstructionWith(
+          instruction, new (GetGraph()->GetArena()) HMul(type, input_other, reciprocal));
+      RecordSimplification();
+      return;
+    }
   }
 }