cmd/9g: use REGZERO instead of REG_R0 if we want the zero register

This will make the intention clearer.
This is migrated from pre-c2go CL 4930.

Change-Id: I9103126a05323daedd729a43b94b2be8cd7408c9
Signed-off-by: Shenghou Ma <minux@golang.org>
Reviewed-on: https://go-review.googlesource.com/7410
Reviewed-by: Austin Clements <austin@google.com>

diff --git a/src/cmd/9g/ggen.go b/src/cmd/9g/ggen.go
index 6bf1d5637364fbcf63f61b8010c6b0cb1ef7edd4..77b1840559f43b313acc6a2d80b2ce4c03aff390 100644 (file)
--- a/src/cmd/9g/ggen.go
+++ b/src/cmd/9g/ggen.go
@@ -223,7 +223,7 @@ func ginscall(f *gc.Node, proc int) {
                        gc.Nodreg(&reg, gc.Types[gc.TINT64], ppc64.REG_R3)
                        p := gins(ppc64.ACMP, &reg, nil)
                        p.To.Type = obj.TYPE_REG
-                       p.To.Reg = ppc64.REG_R0
+                       p.To.Reg = ppc64.REGZERO
                        p = gc.Gbranch(ppc64.ABEQ, nil, +1)
                        cgen_ret(nil)
                        gc.Patch(p, gc.Pc)
@@ -745,7 +745,7 @@ func clearfat(nl *gc.Node) {
        }
 
        var r0 gc.Node
-       gc.Nodreg(&r0, gc.Types[gc.TUINT64], ppc64.REG_R0) // r0 is always zero
+       gc.Nodreg(&r0, gc.Types[gc.TUINT64], ppc64.REGZERO)
        var dst gc.Node
        gc.Nodreg(&dst, gc.Types[gc.Tptr], ppc64.REGRT1)
        reg[ppc64.REGRT1-ppc64.REG_R0]++
@@ -841,7 +841,7 @@ func expandchecks(firstp *obj.Prog) {
                        p->from.type = TYPE_CONST;
                        p->from.offset = 4;
                        p->from.reg = 0;
-                       p->reg = REG_R0;
+                       p->reg = REGZERO;
                        p->to.type = TYPE_REG;
                        p->to.reg = reg;
                */
@@ -876,9 +876,9 @@ func expandchecks(firstp *obj.Prog) {
                p2.As = ppc64.AMOVD
 
                p2.From.Type = obj.TYPE_REG
-               p2.From.Reg = ppc64.REG_R0
+               p2.From.Reg = ppc64.REGZERO
                p2.To.Type = obj.TYPE_MEM
-               p2.To.Reg = ppc64.REG_R0
+               p2.To.Reg = ppc64.REGZERO
                p2.To.Offset = 0
        }
 }