diff --git a/src/cmd/compile/internal/amd64/ggen.go b/src/cmd/compile/internal/amd64/ggen.go
index f065bb4dd4..b5847d48b9 100644
--- a/src/cmd/compile/internal/amd64/ggen.go
+++ b/src/cmd/compile/internal/amd64/ggen.go
@@ -58,7 +58,6 @@ func zerorange(pp *objw.Progs, p *obj.Prog, off, cnt int64, state *uint32) *obj.
 	const (
 		r13 = 1 << iota // if R13 is already zeroed.
 		x15             // if X15 is already zeroed. Note: in new ABI, X15 is always zero.
-		rax             // if RAX is already zeroed.
 	)
 
 	if cnt == 0 {
@@ -117,18 +116,33 @@ func zerorange(pp *objw.Progs, p *obj.Prog, off, cnt int64, state *uint32) *obj.
 		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_R12, 0, obj.TYPE_REG, x86.REG_DI, 0)
 
 	} else {
-		// Note: here we have to use RAX since it is an implicit input
-		// for the REPSTOSQ below. This is going to be problematic when
-		// regabi is in effect; this will be fixed in a forthcoming CL.
-		if *state&rax == 0 {
-			p = pp.Append(p, x86.AMOVQ, obj.TYPE_CONST, 0, 0, obj.TYPE_REG, x86.REG_AX, 0)
-			*state |= rax
-		}
+		// When the register ABI is in effect, at this point in the
+		// prolog we may have live values in all of RAX,RDI,RCX. Save
+		// them off to registers before the REPSTOSQ below, then
+		// restore. Note that R12 and R13 are always available as
+		// scratch regs; here we also use R15 (this is safe to do
+		// since there won't be any globals accessed in the prolog).
+		// See rewriteToUseGot() in obj6.go for more on r15 use.
 
+		// Save rax/rdi/rcx
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_DI, 0, obj.TYPE_REG, x86.REG_R12, 0)
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_AX, 0, obj.TYPE_REG, x86.REG_R13, 0)
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_CX, 0, obj.TYPE_REG, x86.REG_R15, 0)
+
+		// Set up the REPSTOSQ and kick it off.
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_CONST, 0, 0, obj.TYPE_REG, x86.REG_AX, 0)
 		p = pp.Append(p, x86.AMOVQ, obj.TYPE_CONST, 0, cnt/int64(types.RegSize), obj.TYPE_REG, x86.REG_CX, 0)
 		p = pp.Append(p, leaptr, obj.TYPE_MEM, x86.REG_SP, off, obj.TYPE_REG, x86.REG_DI, 0)
 		p = pp.Append(p, x86.AREP, obj.TYPE_NONE, 0, 0, obj.TYPE_NONE, 0, 0)
 		p = pp.Append(p, x86.ASTOSQ, obj.TYPE_NONE, 0, 0, obj.TYPE_NONE, 0, 0)
+
+		// Restore rax/rdi/rcx
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_R12, 0, obj.TYPE_REG, x86.REG_DI, 0)
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_R13, 0, obj.TYPE_REG, x86.REG_AX, 0)
+		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_R15, 0, obj.TYPE_REG, x86.REG_CX, 0)
+
+		// Record the fact that r13 is no longer zero.
+		*state &= ^uint32(r13)
 	}
 
 	return p
diff --git a/src/cmd/compile/internal/test/zerorange_test.go b/src/cmd/compile/internal/test/zerorange_test.go
index cb1a6e04e4..ec87136157 100644
--- a/src/cmd/compile/internal/test/zerorange_test.go
+++ b/src/cmd/compile/internal/test/zerorange_test.go
@@ -4,7 +4,9 @@
 
 package test
 
-import "testing"
+import (
+	"testing"
+)
 
 var glob = 3
 var globp *int64
@@ -94,3 +96,90 @@ func testZeroRange136(t *testing.T) (r, s, t2, u, v, w, x, y, r1, s1, t1, u1, v1
 	globp = &z1
 	return
 }
+
+type S struct {
+	x [2]uint64
+	p *uint64
+	y [2]uint64
+	q uint64
+}
+
+type M struct {
+	x [8]uint64
+	p *uint64
+	y [8]uint64
+	q uint64
+}
+
+type L struct {
+	x [4096]uint64
+	p *uint64
+	y [4096]uint64
+	q uint64
+}
+
+//go:noinline
+func triggerZerorangeLarge(f, g, h uint64) (rv0 uint64) {
+	ll := L{p: &f}
+	da := f
+	rv0 = f + g + h
+	defer func(dl L, i uint64) {
+		rv0 += dl.q + i
+	}(ll, da)
+	return rv0
+}
+
+//go:noinline
+func triggerZerorangeMedium(f, g, h uint64) (rv0 uint64) {
+	ll := M{p: &f}
+	rv0 = f + g + h
+	defer func(dm M, i uint64) {
+		rv0 += dm.q + i
+	}(ll, f)
+	return rv0
+}
+
+//go:noinline
+func triggerZerorangeSmall(f, g, h uint64) (rv0 uint64) {
+	ll := S{p: &f}
+	rv0 = f + g + h
+	defer func(ds S, i uint64) {
+		rv0 += ds.q + i
+	}(ll, f)
+	return rv0
+}
+
+// This test was created as a follow up to issue #45372, to help
+// improve coverage of the compiler's arch-specific "zerorange"
+// function, which is invoked to zero out ambiguously live portions of
+// the stack frame in certain specific circumstances.
+//
+// In the current compiler implementation, for zerorange to be
+// invoked, we need to have an ambiguously live variable that needs
+// zeroing. One way to trigger this is to have a function with an
+// open-coded defer, where the opendefer function has an argument that
+// contains a pointer (this is what's used below).
+//
+// At the moment this test doesn't do any specific checking for
+// code sequence, or verification that things were properly set to zero,
+// this seems as though it would be too tricky and would result
+// in a "brittle" test.
+//
+// The small/medium/large scenarios below are inspired by the amd64
+// implementation of zerorange, which generates different code
+// depending on the size of the thing that needs to be zeroed out
+// (I've verified at the time of the writing of this test that it
+// exercises the various cases).
+//
+func TestZerorange45372(t *testing.T) {
+	if r := triggerZerorangeLarge(101, 303, 505); r != 1010 {
+		t.Errorf("large: wanted %d got %d", 1010, r)
+	}
+	if r := triggerZerorangeMedium(101, 303, 505); r != 1010 {
+		t.Errorf("medium: wanted %d got %d", 1010, r)
+	}
+	if r := triggerZerorangeSmall(101, 303, 505); r != 1010 {
+		t.Errorf("small: wanted %d got %d", 1010, r)
+	}
+
+}