cmd/compile: use opregreg for x86.AXOR* ops

Change-Id: Id087d86261744559685c687aa7bad6c55466f1b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/369020
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Trust: Alex Rakoczy <alex@golang.org>

diff --git a/src/cmd/compile/internal/amd64/ssa.go b/src/cmd/compile/internal/amd64/ssa.go
index 8ec54a8b03762a99c68f9f4a6672c5935807489f..0a3f80191bf812f373d5e5d04bebeb50c61ef93e 100644 (file)
--- a/src/cmd/compile/internal/amd64/ssa.go
+++ b/src/cmd/compile/internal/amd64/ssa.go
@@ -288,11 +288,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
                r := v.Args[1].Reg()
 
                // Zero extend dividend.
-               c := s.Prog(x86.AXORL)
-               c.From.Type = obj.TYPE_REG
-               c.From.Reg = x86.REG_DX
-               c.To.Type = obj.TYPE_REG
-               c.To.Reg = x86.REG_DX
+               opregreg(s, x86.AXORL, x86.REG_DX, x86.REG_DX)
 
                // Issue divide.
                p := s.Prog(v.Op.Asm())
@@ -362,11 +358,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
                        n1.To.Reg = x86.REG_AX
 
                        // n % -1 == 0
-                       n2 := s.Prog(x86.AXORL)
-                       n2.From.Type = obj.TYPE_REG
-                       n2.From.Reg = x86.REG_DX
-                       n2.To.Type = obj.TYPE_REG
-                       n2.To.Reg = x86.REG_DX
+                       opregreg(s, x86.AXORL, x86.REG_DX, x86.REG_DX)
 
                        // TODO(khr): issue only the -1 fixup code we need.
                        // For instance, if only the quotient is used, no point in zeroing the remainder.
@@ -744,11 +736,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
                // If flags aren't live (indicated by v.Aux == nil),
                // then we can rewrite MOV $0, AX into XOR AX, AX.
                if v.AuxInt == 0 && v.Aux == nil {
-                       p := s.Prog(x86.AXORL)
-                       p.From.Type = obj.TYPE_REG
-                       p.From.Reg = x
-                       p.To.Type = obj.TYPE_REG
-                       p.To.Reg = x
+                       opregreg(s, x86.AXORL, x, x)
                        break
                }
 
@@ -1142,11 +1130,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
                        // POPCNT/TZCNT/LZCNT have a false dependency on the destination register on Intel cpus.
                        // TZCNT/LZCNT problem affects pre-Skylake models. See discussion at https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62011#c7.
                        // Xor register with itself to break the dependency.
-                       p := s.Prog(x86.AXORL)
-                       p.From.Type = obj.TYPE_REG
-                       p.From.Reg = v.Reg()
-                       p.To.Type = obj.TYPE_REG
-                       p.To.Reg = v.Reg()
+                       opregreg(s, x86.AXORL, v.Reg(), v.Reg())
                }
                p := s.Prog(v.Op.Asm())
                p.From.Type = obj.TYPE_REG