[turbofan] Inline last remaining WhichPowerOf2Abs use.

R=clemensh@chromium.org

Change-Id: Iecd5fc789b74ae8bcb4bdcb98fcf248c8bc6f6e7
Reviewed-on: https://chromium-review.googlesource.com/568478
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46668}

src/compiler/machine-operator-reducer.cc

@@ -800,8 +800,8 @@ Reduction MachineOperatorReducer::ReduceInt32Div(Node* node) {
     int32_t const divisor = m.right().Value();
     Node* const dividend = m.left().node();
     Node* quotient = dividend;
-    if (divisor == kMinInt || base::bits::IsPowerOfTwo(Abs(divisor))) {
-      uint32_t const shift = WhichPowerOf2Abs(divisor);
+    if (base::bits::IsPowerOfTwo(Abs(divisor))) {
+      uint32_t const shift = WhichPowerOf2(Abs(divisor));
       DCHECK_NE(0u, shift);
       if (shift > 1) {
         quotient = Word32Sar(quotient, 31);

src/utils.h

@@ -227,11 +227,6 @@ inline double Pow(double x, double y) {
   return std::pow(x, y);
 }
 
-// TODO(svenpanne) Clean up the whole power-of-2 mess.
-inline int32_t WhichPowerOf2Abs(int32_t x) {
-  return (x == kMinInt) ? 31 : WhichPowerOf2(Abs(x));
-}
-
 
 // ----------------------------------------------------------------------------
 // BitField is a help template for encoding and decode bitfield with