From 310e3b428cfd181b51723276e6563b90d670da06 Mon Sep 17 00:00:00 2001
From: Kyryl Melekhin <k.melekhin@gmail.com>
Date: Tue, 8 Sep 2020 22:12:01 +0000
Subject: [PATCH] (bug caused by tcc intristics) reproduce bug: $ ./configure
 --cc=gcc $ make $ make install (OK) run a test:

extern int printf(const char *str, ...);
int main()
{
        int t2 = (int)(-1.847759065f * 4096);
        printf("%d\n", t2);
}

$ tcc test.c
$ ./a.out
$ -7568
(OK)

(self compiled now)
$ ./configure --cc=tcc
$ make
$ make install
(OK)

$ tcc test.c
$ ./a.out
$ 7568
(WRONG!!!)

why:
gcc does not have intristics for
uint to long double conversion
therefore it does cast implicitly, so
the sign bit is preserved, but this does
not happen when __fixunsxfdi is called
because tcc was bootstrapped.

solution:
force cast to int64 and preserve the
sign bit.

side effects:
not found.
---
 tccgen.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tccgen.c b/tccgen.c
index dd6a497a..305a082b 100644
--- a/tccgen.c
+++ b/tccgen.c
@@ -3478,7 +3478,7 @@ again:
                 vtop->c.i = (vtop->c.ld != 0);
             } else {
                 if(sf)
-                    vtop->c.i = vtop->c.ld;
+                    vtop->c.i = (int64_t)vtop->c.ld;
                 else if (sbt_bt == VT_LLONG || (PTR_SIZE == 8 && sbt == VT_PTR))
                     ;
                 else if (sbt & VT_UNSIGNED)
-- 
2.11.4.GIT