diff --git a/src/cmd/compile/internal/ssa/debug.go b/src/cmd/compile/internal/ssa/debug.go
index ee522f41ef..2f379c9e2c 100644
--- a/src/cmd/compile/internal/ssa/debug.go
+++ b/src/cmd/compile/internal/ssa/debug.go
@@ -1362,9 +1362,6 @@ func BuildFuncDebugNoOptimized(ctxt *obj.Link, f *Func, loggingEnabled bool, sta
 	// Locate the value corresponding to the last spill of
 	// an input register.
 	afterPrologVal := locatePrologEnd(f)
-	if afterPrologVal == ID(-1) {
-		panic(fmt.Sprintf("internal error: f=%s: can't locate after prolog value", f.Name))
-	}
 
 	// Walk the input params again and process the register-resident elements.
 	pidx := 0
@@ -1381,6 +1378,15 @@ func BuildFuncDebugNoOptimized(ctxt *obj.Link, f *Func, loggingEnabled bool, sta
 		slid := len(fd.VarSlots)
 		fd.VarSlots = append(fd.VarSlots, []SlotID{SlotID(slid)})
 
+		if afterPrologVal == ID(-1) {
+			// This can happen for degenerate functions with infinite
+			// loops such as that in issue 45948. In such cases, leave
+			// the var/slot set up for the param, but don't try to
+			// emit a location list.
+			pidx++
+			continue
+		}
+
 		// Param is arriving in one or more registers. We need a 2-element
 		// location expression for it. First entry in location list
 		// will correspond to lifetime in input registers.
diff --git a/test/fixedbugs/issue45948.go b/test/fixedbugs/issue45948.go
new file mode 100644
index 0000000000..37f8e70e2b
--- /dev/null
+++ b/test/fixedbugs/issue45948.go
@@ -0,0 +1,16 @@
+// compile -N
+
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Issue 45948: assert in debug generation for degenerate
+// function with infinite loop.
+
+package p
+
+func f(p int) {
+L:
+	goto L
+
+}