Make constant propagation to fold x == x and re-run type propagation for better range analysis.

runtime/vm/intermediate_language_x64.cc

Index: runtime/vm/intermediate_language_x64.cc
===================================================================
--- runtime/vm/intermediate_language_x64.cc	(revision 23800)
+++ runtime/vm/intermediate_language_x64.cc	(working copy)
@@ -435,8 +435,6 @@
 
 LocationSummary* EqualityCompareInstr::MakeLocationSummary() const {
   const intptr_t kNumInputs = 2;
-  const bool is_checked_strict_equal =
-      HasICData() && ic_data()->AllTargetsHaveSameOwner(kInstanceCid);
   if (receiver_class_id() == kDoubleCid) {
     const intptr_t kNumTemps =  0;
     LocationSummary* locs =
@@ -460,7 +458,7 @@
     locs->set_out(Location::RequiresRegister());
     return locs;
   }
-  if (is_checked_strict_equal) {
+  if (is_checked_strict_equal()) {
     const intptr_t kNumTemps = 1;
     LocationSummary* locs =
         new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
@@ -888,9 +886,7 @@
     EmitDoubleComparisonOp(compiler, *locs(), kind(), kNoBranch);
     return;
   }
-  const bool is_checked_strict_equal =
-      HasICData() && ic_data()->AllTargetsHaveSameOwner(kInstanceCid);
-  if (is_checked_strict_equal) {
+  if (is_checked_strict_equal()) {
     EmitCheckedStrictEqual(compiler, *ic_data(), *locs(), kind(), kNoBranch,
                            deopt_id());
     return;
@@ -927,9 +923,7 @@
     EmitDoubleComparisonOp(compiler, *locs(), kind(), branch);
     return;
   }
-  const bool is_checked_strict_equal =
-      HasICData() && ic_data()->AllTargetsHaveSameOwner(kInstanceCid);
-  if (is_checked_strict_equal) {
+  if (is_checked_strict_equal()) {
     EmitCheckedStrictEqual(compiler, *ic_data(), *locs(), kind(), branch,
                            deopt_id());
     return;