src/cmd/compile/internal/gc/subr.go      | 12 ++++++++++--
 src/cmd/compile/internal/gc/typecheck.go |  2 +-
 test/fixedbugs/issue38117.go             | 17 +++++++++++++++++

diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index 3b085a0d6423040f26bd8d4888e9436fcb5db539..73ed34f86a51a3646ee2d224394f70d7ebd6ef23 100644
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -542,7 +542,7 @@
 // Is type src assignment compatible to type dst?
 // If so, return op code to use in conversion.
 // If not, return 0.
-func assignop(src *types.Type, dst *types.Type, why *string) Op {
+func assignop(src, dst *types.Type, why *string) Op {
 	if why != nil {
 		*why = ""
 	}
@@ -665,7 +665,8 @@
 // Can we convert a value of type src to a value of type dst?
 // If so, return op code to use in conversion (maybe OCONVNOP).
 // If not, return 0.
-func convertop(src *types.Type, dst *types.Type, why *string) Op {
+// srcConstant indicates whether the value of type src is a constant.
+func convertop(srcConstant bool, src, dst *types.Type, why *string) Op {
 	if why != nil {
 		*why = ""
 	}
@@ -738,6 +739,13 @@ 	if src.IsComplex() && dst.IsComplex() {
 		if simtype[src.Etype] == simtype[dst.Etype] {
 			return OCONVNOP
 		}
+		return OCONV
+	}
+
+	// Special case for constant conversions: any numeric
+	// conversion is potentially okay. We'll validate further
+	// within evconst. See #38117.
+	if srcConstant && (src.IsInteger() || src.IsFloat() || src.IsComplex()) && (dst.IsInteger() || dst.IsFloat() || dst.IsComplex()) {
 		return OCONV
 	}
 
diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index ae2e16760d197743b10b22b7bc32de5602cb8c71..2ed736367f97cfb0be1bc0c44b1b3e96925596f1 100644
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -1634,7 +1634,7 @@ 			n.Type = nil
 			return n
 		}
 		var why string
-		n.Op = convertop(t, n.Type, &why)
+		n.Op = convertop(n.Left.Op == OLITERAL, t, n.Type, &why)
 		if n.Op == 0 {
 			if !n.Diag() && !n.Type.Broke() && !n.Left.Diag() {
 				yyerror("cannot convert %L to type %v%s", n.Left, n.Type, why)
diff --git a/test/fixedbugs/issue38117.go b/test/fixedbugs/issue38117.go
new file mode 100644
index 0000000000000000000000000000000000000000..11edef7f2532d5078a2864f69e065c6e3b27c9d8
--- /dev/null
+++ b/test/fixedbugs/issue38117.go
@@ -0,0 +1,17 @@
+// errorcheck
+
+// Copyright 2020 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.
+
+// cmd/compile erroneously rejected conversions of constant values
+// between int/float and complex types.
+
+package p
+
+const (
+	_ = int(complex64(int(0)))
+	_ = float64(complex128(float64(0)))
+
+	_ = int8(complex128(1000)) // ERROR "overflow"
+)