Merge 15827, 15842, and 15912 into 3.19

src/mips/lithium-mips.cc

Index: src/mips/lithium-mips.cc
diff --git a/src/mips/lithium-mips.cc b/src/mips/lithium-mips.cc
index 1b94332320c771471abdab247d88e06d21caabc5..293266764500e4926f8802ded10b15e25ece9b20 100644
--- a/src/mips/lithium-mips.cc
+++ b/src/mips/lithium-mips.cc
@@ -715,11 +715,6 @@ LInstruction* LChunkBuilder::DoEnvironmentMarker(HEnvironmentMarker* instr) {
 }
 
 
-LInstruction* LChunkBuilder::DoSoftDeoptimize(HSoftDeoptimize* instr) {
-  return AssignEnvironment(new(zone()) LDeoptimize);
-}
-
-
 LInstruction* LChunkBuilder::DoDeoptimize(HDeoptimize* instr) {
   return AssignEnvironment(new(zone()) LDeoptimize);
 }