From cc75a9b12be08b3c2ff848af7754230da15cc940 Mon Sep 17 00:00:00 2001
From: Stephen Heumann <stephenheumann@gmail.com>
Date: Mon, 10 Oct 2016 20:02:21 -0500
Subject: [PATCH] Fix a problem where a conversion to a smaller type could be
 improperly omitted when followed by a conversion to a larger type.

This also fixes a logic error that may have permitted other conversions to be improperly omitted in some cases.

The following program demonstrates the problem (should print 211):

#pragma optimize 1
#include <stdio.h>
int main(void)
{
        unsigned int i = 1234;
        long l = (unsigned char)(i+1);
        printf("%li\n", l);
}
---
 DAG.pas | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/DAG.pas b/DAG.pas
index 5039884..3b505d2 100644
--- a/DAG.pas
+++ b/DAG.pas
@@ -1135,7 +1135,7 @@ case op^.opcode of			{check for optimizations of this node}
          end {if}
       else if op^.left^.opcode = pc_cnv then begin
          doit := false;
-         firsttype.i := (op^.q & $00F0) >> 4;
+         firsttype.i := (op^.left^.q & $00F0) >> 4;
          if fromType.optype in [cgReal,cgDouble,cgComp,cgExtended] then begin
             if toType.optype in [cgReal,cgDouble,cgComp,cgExtended] then
                doit := true;
@@ -1152,6 +1152,9 @@ case op^.opcode of			{check for optimizations of this node}
             if TypeSize(firstType.optype) = TypeSize(fromType.optype) then
                if TypeSize(firstType.optype) = TypeSize(toType.optype) then
                   doit := true;
+            if TypeSize(fromType.optype) < TypeSize(firstType.optype) then
+               if TypeSize(fromType.optype) < TypeSize(toType.optype) then
+                  doit := false;        {disable optimization in invalid cases}
             end; {else}
          if doit then begin
             op^.q := (op^.left^.q & $00F0) | (op^.q & $000F);