From 7f94876fa87274c29ef10b38c783c95408054e97 Mon Sep 17 00:00:00 2001
From: Stephen Heumann <stephenheumann@gmail.com>
Date: Mon, 26 Mar 2018 18:30:45 -0500
Subject: [PATCH] Fix mis-optimization of "expression && non-zero constant"
 operations with 32-bit type.

The previous code may have been intended to convert this to a "!=0" test, which would have been valid if correctly implemented, but with the current code generator that actually yields worse code than the original version, so for now I just removed the optimization for this case.

This problem could lead to crashes in code like the following (derived from a csmith-generated test case):

#pragma optimize 1
int main(int argc, char *argv[]){
    long l_57 = argc;

    return (4 ^ l_57) && 6;
}
---
 DAG.pas | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/DAG.pas b/DAG.pas
index c5e2121..39a6984 100644
--- a/DAG.pas
+++ b/DAG.pas
@@ -1569,9 +1569,7 @@ case op^.opcode of			{check for optimizations of this node}
                      end; {with}
                   opv := op^.right;
                   end; {if}
-               end {if}
-            else
-               op^.opcode := pc_neq;
+               end; {if}
             end; {if}
          end {if}
       else if op^.left^.opcode = pc_ldc then