cmd/compile: remove nil check if followed by storezero on ARM64, MIPS64

Change-Id: Ib90c92056fa70b27feb734837794ef53e842c41a
Reviewed-on: https://go-review.googlesource.com/28513
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

src/cmd/compile/internal/arm64/ssa.go

@@ -637,7 +637,8 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 				ssa.OpARM64MOVWload, ssa.OpARM64MOVWUload, ssa.OpARM64MOVDload,
 				ssa.OpARM64FMOVSload, ssa.OpARM64FMOVDload,
 				ssa.OpARM64MOVBstore, ssa.OpARM64MOVHstore, ssa.OpARM64MOVWstore, ssa.OpARM64MOVDstore,
-				ssa.OpARM64FMOVSstore, ssa.OpARM64FMOVDstore:
+				ssa.OpARM64FMOVSstore, ssa.OpARM64FMOVDstore,
+				ssa.OpARM64MOVBstorezero, ssa.OpARM64MOVHstorezero, ssa.OpARM64MOVWstorezero, ssa.OpARM64MOVDstorezero:
 				// arg0 is ptr, auxint is offset
 				if w.Args[0] == v.Args[0] && w.Aux == nil && w.AuxInt >= 0 && w.AuxInt < minZeroPage {
 					if gc.Debug_checknil != 0 && int(v.Line) > 1 {

src/cmd/compile/internal/mips64/ssa.go

@@ -660,7 +660,8 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 				ssa.OpMIPS64MOVWload, ssa.OpMIPS64MOVWUload, ssa.OpMIPS64MOVVload,
 				ssa.OpMIPS64MOVFload, ssa.OpMIPS64MOVDload,
 				ssa.OpMIPS64MOVBstore, ssa.OpMIPS64MOVHstore, ssa.OpMIPS64MOVWstore, ssa.OpMIPS64MOVVstore,
-				ssa.OpMIPS64MOVFstore, ssa.OpMIPS64MOVDstore:
+				ssa.OpMIPS64MOVFstore, ssa.OpMIPS64MOVDstore,
+				ssa.OpMIPS64MOVBstorezero, ssa.OpMIPS64MOVHstorezero, ssa.OpMIPS64MOVWstorezero, ssa.OpMIPS64MOVVstorezero:
 				// arg0 is ptr, auxint is offset
 				if w.Args[0] == v.Args[0] && w.Aux == nil && w.AuxInt >= 0 && w.AuxInt < minZeroPage {
 					if gc.Debug_checknil != 0 && int(v.Line) > 1 {