diff --git a/src/cmd/compile/internal/base/debug.go b/src/cmd/compile/internal/base/debug.go
index 083fdf8fb1..7e4adef706 100644
--- a/src/cmd/compile/internal/base/debug.go
+++ b/src/cmd/compile/internal/base/debug.go
@@ -17,11 +17,11 @@ var Debug DebugFlags
 // Each setting is name=value; for ints, name is short for name=1.
 type DebugFlags struct {
 	Append                        int    `help:"print information about append compilation"`
-	Checkptr                      int    `help:"instrument unsafe pointer conversions\n0: instrumentation disabled\n1: conversions involving unsafe.Pointer are instrumented\n2: conversions to unsafe.Pointer force heap allocation"`
+	Checkptr                      int    `help:"instrument unsafe pointer conversions\n0: instrumentation disabled\n1: conversions involving unsafe.Pointer are instrumented\n2: conversions to unsafe.Pointer force heap allocation" concurrent:"ok"`
 	Closure                       int    `help:"print information about closure compilation"`
 	DclStack                      int    `help:"run internal dclstack check"`
 	Defer                         int    `help:"print information about defer compilation"`
-	DisableNil                    int    `help:"disable nil checks"`
+	DisableNil                    int    `help:"disable nil checks" concurrent:"ok"`
 	DumpPtrs                      int    `help:"show Node pointers values in dump output"`
 	DwarfInl                      int    `help:"print information about DWARF inlined function creation"`
 	Export                        int    `help:"print export data"`
@@ -29,27 +29,27 @@ type DebugFlags struct {
 	GCAdjust                      int    `help:"log adjustments to GOGC" concurrent:"ok"`
 	GCProg                        int    `help:"print dump of GC programs"`
 	Gossahash                     string `help:"hash value for use in debugging the compiler"`
-	InlFuncsWithClosures          int    `help:"allow functions with closures to be inlined"`
+	InlFuncsWithClosures          int    `help:"allow functions with closures to be inlined" concurrent:"ok"`
 	Libfuzzer                     int    `help:"enable coverage instrumentation for libfuzzer"`
 	LocationLists                 int    `help:"print information about DWARF location list creation"`
 	Nil                           int    `help:"print information about nil checks"`
-	NoOpenDefer                   int    `help:"disable open-coded defers"`
-	NoRefName                     int    `help:"do not include referenced symbol names in object file"`
+	NoOpenDefer                   int    `help:"disable open-coded defers" concurrent:"ok"`
+	NoRefName                     int    `help:"do not include referenced symbol names in object file" concurrent:"ok"`
 	PCTab                         string `help:"print named pc-value table\nOne of: pctospadj, pctofile, pctoline, pctoinline, pctopcdata"`
 	Panic                         int    `help:"show all compiler panics"`
 	Reshape                       int    `help:"print information about expression reshaping"`
 	Shapify                       int    `help:"print information about shaping recursive types"`
 	Slice                         int    `help:"print information about slice compilation"`
-	SoftFloat                     int    `help:"force compiler to emit soft-float code"`
+	SoftFloat                     int    `help:"force compiler to emit soft-float code" concurrent:"ok"`
 	SyncFrames                    int    `help:"how many writer stack frames to include at sync points in unified export data"`
 	TypeAssert                    int    `help:"print information about type assertion inlining"`
-	TypecheckInl                  int    `help:"eager typechecking of inline function bodies"`
+	TypecheckInl                  int    `help:"eager typechecking of inline function bodies" concurrent:"ok"`
 	Unified                       int    `help:"enable unified IR construction"`
 	WB                            int    `help:"print information about write barriers"`
 	ABIWrap                       int    `help:"print information about ABI wrapper generation"`
-	MayMoreStack                  string `help:"call named function before all stack growth checks"`
-	InlineHotCallSiteCDFThreshold string `help:"cummulative threshold percentage for determining call sites as hot candidates for inlining"`
-	InlineHotBudget               int    `help:"inline budget for hot functions"`
+	MayMoreStack                  string `help:"call named function before all stack growth checks" concurrent:"ok"`
+	InlineHotCallSiteCDFThreshold string `help:"cummulative threshold percentage for determining call sites as hot candidates for inlining" concurrent:"ok"`
+	InlineHotBudget               int    `help:"inline budget for hot functions" concurrent:"ok"`
 	PGOInline                     int    `help:"debug profile-guided inlining"`
 
 	ConcurrentOk bool // true if only concurrentOk flags seen
diff --git a/src/cmd/go/internal/work/gc.go b/src/cmd/go/internal/work/gc.go
index de32ad9158..cff4773315 100644
--- a/src/cmd/go/internal/work/gc.go
+++ b/src/cmd/go/internal/work/gc.go
@@ -235,20 +235,6 @@ func gcBackendConcurrency(gcflags []string) int {
 		log.Fatalf("GO19CONCURRENTCOMPILATION must be 0, 1, or unset, got %q", e)
 	}
 
-CheckFlags:
-	for _, flag := range gcflags {
-		// Concurrent compilation is presumed incompatible with any gcflags,
-		// except for known commonly used flags.
-		// If the user knows better, they can manually add their own -c to the gcflags.
-		switch flag {
-		case "-N", "-l", "-S", "-B", "-C", "-I", "-shared":
-			// OK
-		default:
-			canDashC = false
-			break CheckFlags
-		}
-	}
-
 	// TODO: Test and delete these conditions.
 	if cfg.ExperimentErr != nil || cfg.Experiment.FieldTrack || cfg.Experiment.PreemptibleLoops {
 		canDashC = false