From ec6624dfc767e9a65abe143a04c3fe6f58d0f4fe Mon Sep 17 00:00:00 2001
From: Randy Heit <rheit@zdoom.fake>
Date: Fri, 1 Nov 2013 22:05:49 -0500
Subject: [PATCH] Prioritize single->double conversions for FindBestProto()

- The binary form of ZCC_OpInfoType::FindBestProto() needs special
  handling for conversion from single to double precision floating point
  so that it doesn't choose an integer form over a floating point form
  when picking the best prototype.
---
 src/zscript/zcc_expr.cpp | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/zscript/zcc_expr.cpp b/src/zscript/zcc_expr.cpp
index dc7a08d1cc..32d0c9374c 100644
--- a/src/zscript/zcc_expr.cpp
+++ b/src/zscript/zcc_expr.cpp
@@ -10,6 +10,8 @@
 
 #define luai_nummod(a,b)        ((a) - floor((a)/(b))*(b))
 
+static void FtoD(ZCC_ExprConstant *expr, FSharedStringArena &str_arena);
+
 ZCC_OpInfoType ZCC_OpInfo[PEX_COUNT_OF] =
 {
 #define xx(a,z)	{ #a, NULL },
@@ -134,7 +136,19 @@ ZCC_OpProto *ZCC_OpInfoType::FindBestProto(
 		{ // one or both operator types are unreachable
 			continue;
 		}
-		int dist = MIN(dist1, dist2);
+		// Do not count F32->F64 conversions in the distance comparisons. If we do, then
+		// [[float32 (op) int]] will choose the integer version instead of the floating point
+		// version, which we do not want.
+		int test_dist1 = dist1, test_dist2 = dist2;
+		if (routes[0][cur_route1][0]->ConvertConstant == FtoD)
+		{
+			test_dist1--;
+		}
+		if (routes[1][cur_route2][0]->ConvertConstant == FtoD)
+		{
+			test_dist2--;
+		}
+		int dist = MIN(test_dist1, test_dist2);
 		if (dist < best_low_dist)
 		{
 			best_low_dist = dist;