diff --git a/gotooltest/setup.go b/gotooltest/setup.go
index 84705cfa..b1092c92 100644
--- a/gotooltest/setup.go
+++ b/gotooltest/setup.go
@@ -10,7 +10,6 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"go/build"
 	"os/exec"
 	"path/filepath"
 	"regexp"
@@ -22,7 +21,7 @@ import (
 )
 
 var (
-	goVersionRegex = regexp.MustCompile(`^go([1-9][0-9]*)\.(0|[1-9][0-9]*)$`)
+	goVersionRegex = regexp.MustCompile(`^go([1-9][0-9]*)\.([1-9][0-9]*)$`)
 
 	goEnv struct {
 		GOROOT      string
@@ -104,27 +103,6 @@ func Setup(p *testscript.Params) error {
 		p.Cmds = make(map[string]func(ts *testscript.TestScript, neg bool, args []string))
 	}
 	p.Cmds["go"] = cmdGo
-	origCondition := p.Condition
-	p.Condition = func(cond string) (bool, error) {
-		if cond == "gc" || cond == "gccgo" {
-			// TODO this reflects the compiler that the current
-			// binary was built with but not necessarily the compiler
-			// that will be used.
-			return cond == runtime.Compiler, nil
-		}
-		if goVersionRegex.MatchString(cond) {
-			for _, v := range build.Default.ReleaseTags {
-				if cond == v {
-					return true, nil
-				}
-			}
-			return false, nil
-		}
-		if origCondition == nil {
-			return false, fmt.Errorf("unknown condition %q", cond)
-		}
-		return origCondition(cond)
-	}
 	return nil
 }
 
diff --git a/testscript/doc.go b/testscript/doc.go
index d4fe1869..ba91db36 100644
--- a/testscript/doc.go
+++ b/testscript/doc.go
@@ -105,6 +105,9 @@ should only run when the condition is satisfied. The predefined conditions are:
  - [link] for whether the OS has hard link support
  - [symlink] for whether the OS has symbolic link support
  - [exec:prog] for whether prog is available for execution (found by exec.LookPath)
+ - [gc] for whether Go was built with gc
+ - [gccgo] for whether Go was built with gccgo
+ - [go1.x] for whether the Go version is 1.x or later
 
 A condition can be negated: [!short] means to run the rest of the line
 when testing.Short() is false.
diff --git a/testscript/testdata/cond.txt b/testscript/testdata/cond.txt
new file mode 100644
index 00000000..60b62c2a
--- /dev/null
+++ b/testscript/testdata/cond.txt
@@ -0,0 +1,11 @@
+[!exec:sh] skip 'sh not found in $PATH'
+
+# test that exactly one of gc and gccgo is set
+[gc] exec sh -c 'echo gc >> go-compiler'
+[gccgo] exec sh -c 'echo gccgo >> go-compiler'
+grep '\A(gc|gccgo)\n\z' go-compiler
+
+# test that go version build tags are set
+[go1.1] exec sh -c 'echo go1.1 >> go-version'
+[go2.1] exec sh -c 'echo go2.1 >> go-version'
+grep '\Ago1\.1\n\z' go-version
\ No newline at end of file
diff --git a/testscript/testscript.go b/testscript/testscript.go
index ea5f51e2..af752e3f 100644
--- a/testscript/testscript.go
+++ b/testscript/testscript.go
@@ -12,6 +12,7 @@ import (
 	"context"
 	"flag"
 	"fmt"
+	"go/build"
 	"io/ioutil"
 	"os"
 	"os/exec"
@@ -30,6 +31,8 @@ import (
 	"github.com/rogpeppe/go-internal/txtar"
 )
 
+var goVersionRegex = regexp.MustCompile(`^go([1-9][0-9]*)\.([1-9][0-9]*)$`)
+
 var execCache par.Cache
 
 // If -testwork is specified, the test prints the name of the temp directory
@@ -572,32 +575,41 @@ func (ts *TestScript) applyScriptUpdates() {
 
 // condition reports whether the given condition is satisfied.
 func (ts *TestScript) condition(cond string) (bool, error) {
-	switch cond {
-	case "short":
+	switch {
+	case cond == "short":
 		return testing.Short(), nil
-	case "net":
+	case cond == "net":
 		return testenv.HasExternalNetwork(), nil
-	case "link":
+	case cond == "link":
 		return testenv.HasLink(), nil
-	case "symlink":
+	case cond == "symlink":
 		return testenv.HasSymlink(), nil
-	case runtime.GOOS, runtime.GOARCH:
-		return true, nil
-	default:
-		if imports.KnownArch[cond] || imports.KnownOS[cond] {
-			return false, nil
-		}
-		if strings.HasPrefix(cond, "exec:") {
-			prog := cond[len("exec:"):]
-			ok := execCache.Do(prog, func() interface{} {
-				_, err := execpath.Look(prog, ts.Getenv)
-				return err == nil
-			}).(bool)
-			return ok, nil
-		}
-		if ts.params.Condition != nil {
-			return ts.params.Condition(cond)
+	case imports.KnownOS[cond]:
+		return cond == runtime.GOOS, nil
+	case imports.KnownArch[cond]:
+		return cond == runtime.GOARCH, nil
+	case strings.HasPrefix(cond, "exec:"):
+		prog := cond[len("exec:"):]
+		ok := execCache.Do(prog, func() interface{} {
+			_, err := execpath.Look(prog, ts.Getenv)
+			return err == nil
+		}).(bool)
+		return ok, nil
+	case cond == "gc" || cond == "gccgo":
+		// TODO this reflects the compiler that the current
+		// binary was built with but not necessarily the compiler
+		// that will be used.
+		return cond == runtime.Compiler, nil
+	case goVersionRegex.MatchString(cond):
+		for _, v := range build.Default.ReleaseTags {
+			if cond == v {
+				return true, nil
+			}
 		}
+		return false, nil
+	case ts.params.Condition != nil:
+		return ts.params.Condition(cond)
+	default:
 		ts.Fatalf("unknown condition %q", cond)
 		panic("unreachable")
 	}