cmd/compile: remove Arch.REGCTXT

Update #16357.

Change-Id: I507676212d7137a62c76de7bfa0ba8dbd68e840f
Reviewed-on: https://go-review.googlesource.com/29358
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Dave Cheney <dave@cheney.net>
diff --git a/src/cmd/compile/internal/amd64/galign.go b/src/cmd/compile/internal/amd64/galign.go
index 9d67812..bb3830b 100644
--- a/src/cmd/compile/internal/amd64/galign.go
+++ b/src/cmd/compile/internal/amd64/galign.go
@@ -19,7 +19,6 @@
 		leaptr = x86.ALEAL
 	}
 	gc.Thearch.REGSP = x86.REGSP
-	gc.Thearch.REGCTXT = x86.REGCTXT
 	gc.Thearch.MAXWIDTH = 1 << 50
 
 	gc.Thearch.Defframe = defframe
diff --git a/src/cmd/compile/internal/arm/galign.go b/src/cmd/compile/internal/arm/galign.go
index 1533f6cf..308b016 100644
--- a/src/cmd/compile/internal/arm/galign.go
+++ b/src/cmd/compile/internal/arm/galign.go
@@ -13,7 +13,6 @@
 func Init() {
 	gc.Thearch.LinkArch = &arm.Linkarm
 	gc.Thearch.REGSP = arm.REGSP
-	gc.Thearch.REGCTXT = arm.REGCTXT
 	gc.Thearch.MAXWIDTH = (1 << 32) - 1
 
 	gc.Thearch.Defframe = defframe
diff --git a/src/cmd/compile/internal/arm64/galign.go b/src/cmd/compile/internal/arm64/galign.go
index 587186f..20a67e3 100644
--- a/src/cmd/compile/internal/arm64/galign.go
+++ b/src/cmd/compile/internal/arm64/galign.go
@@ -13,7 +13,6 @@
 func Init() {
 	gc.Thearch.LinkArch = &arm64.Linkarm64
 	gc.Thearch.REGSP = arm64.REGSP
-	gc.Thearch.REGCTXT = arm64.REGCTXT
 	gc.Thearch.MAXWIDTH = 1 << 50
 
 	gc.Thearch.Defframe = defframe
diff --git a/src/cmd/compile/internal/gc/go.go b/src/cmd/compile/internal/gc/go.go
index 15a179a..d090e5c 100644
--- a/src/cmd/compile/internal/gc/go.go
+++ b/src/cmd/compile/internal/gc/go.go
@@ -346,7 +346,6 @@
 	LinkArch *obj.LinkArch
 
 	REGSP    int
-	REGCTXT  int
 	MAXWIDTH int64
 
 	Defframe func(*obj.Prog)
diff --git a/src/cmd/compile/internal/mips64/galign.go b/src/cmd/compile/internal/mips64/galign.go
index 007938c..4a36a4c 100644
--- a/src/cmd/compile/internal/mips64/galign.go
+++ b/src/cmd/compile/internal/mips64/galign.go
@@ -17,7 +17,6 @@
 		gc.Thearch.LinkArch = &mips.Linkmips64le
 	}
 	gc.Thearch.REGSP = mips.REGSP
-	gc.Thearch.REGCTXT = mips.REGCTXT
 	gc.Thearch.MAXWIDTH = 1 << 50
 
 	gc.Thearch.Defframe = defframe
diff --git a/src/cmd/compile/internal/ppc64/galign.go b/src/cmd/compile/internal/ppc64/galign.go
index 94d338e..186aa29 100644
--- a/src/cmd/compile/internal/ppc64/galign.go
+++ b/src/cmd/compile/internal/ppc64/galign.go
@@ -16,7 +16,6 @@
 		gc.Thearch.LinkArch = &ppc64.Linkppc64le
 	}
 	gc.Thearch.REGSP = ppc64.REGSP
-	gc.Thearch.REGCTXT = ppc64.REGCTXT
 	gc.Thearch.MAXWIDTH = 1 << 50
 
 	gc.Thearch.Defframe = defframe
diff --git a/src/cmd/compile/internal/s390x/galign.go b/src/cmd/compile/internal/s390x/galign.go
index eb2a51a..91b9ed0 100644
--- a/src/cmd/compile/internal/s390x/galign.go
+++ b/src/cmd/compile/internal/s390x/galign.go
@@ -12,7 +12,6 @@
 func Init() {
 	gc.Thearch.LinkArch = &s390x.Links390x
 	gc.Thearch.REGSP = s390x.REGSP
-	gc.Thearch.REGCTXT = s390x.REGCTXT
 	gc.Thearch.MAXWIDTH = 1 << 50
 
 	gc.Thearch.Defframe = defframe
diff --git a/src/cmd/compile/internal/x86/galign.go b/src/cmd/compile/internal/x86/galign.go
index 4b021b6..edac6a0 100644
--- a/src/cmd/compile/internal/x86/galign.go
+++ b/src/cmd/compile/internal/x86/galign.go
@@ -15,7 +15,6 @@
 func Init() {
 	gc.Thearch.LinkArch = &x86.Link386
 	gc.Thearch.REGSP = x86.REGSP
-	gc.Thearch.REGCTXT = x86.REGCTXT
 	switch v := obj.GO386; v {
 	case "387":
 		gc.Thearch.Use387 = true