This change precisely identifies the live range of the

exception operand in a handler block. This avoids confusing
unrelated ranges, which may happen if escape analysis elides
the exception operand.

BUG=chromium:576195
LOG=N

Review URL: https://codereview.chromium.org/1579603005

Cr-Commit-Position: refs/heads/master@{#33271}

src/compiler/register-allocator.cc

@@ -1919,7 +1919,10 @@ void LiveRangeBuilder::ProcessInstructions(const InstructionBlock* block,
         int out_vreg = ConstantOperand::cast(output)->virtual_register();
         live->Remove(out_vreg);
       }
-      if (block->IsHandler() && index == block_start) {
+      if (block->IsHandler() && index == block_start && output->IsAllocated() &&
+          output->IsRegister() &&
+          AllocatedOperand::cast(output)->GetRegister().is(
+              v8::internal::kReturnRegister0)) {
         // The register defined here is blocked from gap start - it is the
         // exception value.
         // TODO(mtrofin): should we explore an explicit opcode for