diff --git a/src/cmd/vet/testdata/asm.go b/src/cmd/vet/testdata/asm.go
index 3f9275c008..e6d6d03106 100644
--- a/src/cmd/vet/testdata/asm.go
+++ b/src/cmd/vet/testdata/asm.go
@@ -42,3 +42,4 @@ func noptr(x int)
 func wrapper(x int)
 
 func f15271() (x uint32)
+func f17584(x float32, y complex64)
diff --git a/src/cmd/vet/testdata/asm1.s b/src/cmd/vet/testdata/asm1.s
index bc8cbc2e79..cac6ed22cd 100644
--- a/src/cmd/vet/testdata/asm1.s
+++ b/src/cmd/vet/testdata/asm1.s
@@ -306,3 +306,10 @@ TEXT ·f15271(SB), NOSPLIT, $0-4
     // Return them.
     PEXTRD $0, X0, x+0(FP)
     RET
+
+// issue 17584
+TEXT ·f17584(SB), NOSPLIT, $12
+	MOVSS	x+0(FP), X0
+	MOVSS	y_real+4(FP), X0
+	MOVSS	y_imag+8(FP), X0
+	RET
diff --git a/src/go/types/sizes.go b/src/go/types/sizes.go
index 6efd0b1394..3bbe5aee40 100644
--- a/src/go/types/sizes.go
+++ b/src/go/types/sizes.go
@@ -79,6 +79,10 @@ func (s *StdSizes) Alignof(T Type) int64 {
 	if a < 1 {
 		return 1
 	}
+	// complex{64,128} are aligned like [2]float{32,64}.
+	if isComplex(T) {
+		a /= 2
+	}
 	if a > s.MaxAlign {
 		return s.MaxAlign
 	}