FWIW, I see the same failures on Gentoo amd64, at 4e5f15c6851c69c4cc5da18209218eb918dbee77 (also tested against 2eb844f8b5ea0ae159eb3fcec78aa50bd8c03f11, but the problem is there as well).
address@hidden ~/src/tinycc $ make test
make -C tests test 'PROGS_CROSS=i386-linux-gnu-tcc i386-w64-mingw32-tcc x86_64-w64-mingw32-tcc arm-linux-fpa-tcc arm-linux-fpa-ld-tcc arm-linux-gnu-tcc arm-linux-gnueabi-tcc c67-tcc'
make[1]: Entering directory '/home/austin/src/tinycc/tests'
------------ hello-exe ------------
../tcc -B.. -I.. -I.. -I../include ../examples/ex1.c -o hello || (../tcc -vv; exit 1) && ./hello
Hello World
------------ hello-run ------------
../tcc -B.. -I.. -I.. -I../include -run ../examples/ex1.c
Hello World
------------ libtest ------------
./libtcc_test lib_path=..
Hello World!
fib(32) = 2178309
add(32, 64) = 96
gcc -o tcctest.gcc tcctest.c -I.. -I.. -w -Wall -g -O2 -fno-strict-aliasing -Wno-pointer-sign -Wno-sign-compare -Wno-unused-result -DCONFIG_LDDIR="\"lib64\"" -DTCC_TARGET_X86_64 -std=gnu99 -O0 -fno-omit-frame-pointer
./tcctest.gcc > test.ref
------------ test3 ------------
../tcc -B.. -I.. -I.. -I../include -DCONFIG_LDDIR="\"lib64\"" -DTCC_TARGET_X86_64 -DONE_SOURCE -run ../tcc.c -B.. -I.. -I.. -I../include -DCONFIG_LDDIR="\"lib64\"" -DTCC_TARGET_X86_64 -DONE_SOURCE -run ../tcc.c -B.. -I.. -I.. -I../include -DCONFIG_LDDIR="\"lib64\"" -DTCC_TARGET_X86_64 -DONE_SOURCE -run ../tcc.c -B.. -I.. -I.. -I../include -run tcctest.c > test.out3
--- test.ref 2014-02-03 16:08:40.010395893 -0800
+++ test.out3 2014-02-03 16:08:40.371390533 -0800
@@ -346,7 +346,7 @@
itof: -1234.000000
lltof: -2334.000000
utof: 2166572288.000000
-ulltof: 18446744073709551616.000000
+ulltof: 2334.000000
float: 42.123455
double: 42.123455
long double: 42.123455
@@ -385,7 +385,7 @@
itof: -1234.000000
lltof: -2334.000000
utof: 2166572288.000000
-ulltof: 18446744073709549568.000000
+ulltof: 2334.000000
float: 42.123455
double: 42.123457
long double: 42.123457
@@ -424,7 +424,7 @@
itof: -1234.000000
lltof: -2334.000000
utof: 2166572288.000000
-ulltof: 18446744073709549282.000000
+ulltof: 2334.000000
float: 42.123455
double: 42.123457
long double: 42.123457
Makefile:125: recipe for target 'test3' failed
make[1]: *** [test3] Error 1
make[1]: Leaving directory '/home/austin/src/tinycc/tests'
Makefile:350: recipe for target 'test' failed
make: *** [test] Error 2
address@hidden ~/src/tinycc $ git describe
release_0_9_26-142-g4e5f15c
address@hidden ~/src/tinycc $ uname -a
Linux aw25 3.12.0-gentoo-devlight-1 #1 SMP Mon Nov 4 19:37:36 Local time zone must be set--see zic m x86_64 Intel(R) Core(TM) i7 CPU 960 @ 3.20GHz GenuineIntel GNU/Linux
address@hidden ~/src/tinycc $ gcc -v
Using built-in specs.
COLLECT_GCC=/usr/x86_64-pc-linux-gnu/gcc-bin/4.8.2/gcc
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-pc-linux-gnu/4.8.2/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /var/tmp/portage/sys-devel/gcc-4.8.2/work/gcc-4.8.2/configure --host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --prefix=/usr --bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/4.8.2 --includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include --datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2 --mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/man --infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/info --with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/4.8.2/include/g++-v4 --with-python-dir=/share/gcc-data/x86_64-pc-linux-gnu/4.8.2/python --enable-languages=c,c++,java,go --enable-obsolete --enable-secureplt --disable-werror --with-system-zlib --disable-nls --enable-checking=release --with-bugurl=
https://bugs.gentoo.org/ --with-pkgversion='Gentoo 4.8.2 p1.3r1, pie-0.5.8r1' --enable-libstdcxx-time --enable-shared --enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu --enable-multilib --with-multilib-list=m32,m64 --disable-altivec --disable-fixed-point --enable-targets=all --enable-libgomp --enable-libmudflap --disable-libssp --disable-libquadmath --enable-lto --without-cloog
Thread model: posix
gcc version 4.8.2 (Gentoo 4.8.2 p1.3r1, pie-0.5.8r1)