-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
We have another VRP related test case for GCC-10.2.0.
We expect A1.c and A2.c should compile to the same codes, but they did
not
-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
We compiled two programs (A1.c, A2.c) by gcc-10.2.0 with -O3 option.
The two programs are equivalent, but resulted in different assembly codes.
Although
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
GCC 8.0.0 for x86_64 miscompiles the following code.
% cat test.c
int a[2] = {0,1};
int x = 129;
int main (void)
{
volatile int v = 0;
int t = x;
for (int i = 0; i
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
GCC 8.0 for x86_64 miscompiles the following code.
% cat test.c
int a[2] = {0,1};
int x = 129;
int main (void)
{
volatile int v = 0;
int t = x;
for (int i = 0; i
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
We compiled two programs (A1.c, A2.c) by GCC-8.0.0 with -O3 option.
We expect the resulting assembly codes would be the same, or at least
A1.c
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
GCC 8.0.0 for x86_64 miscompiles the following code.
Reproduces on gcc-5.1.0 to gcc-6.3.0 and gcc-8.0.0 with -O1, and on gcc-4.4.7
or later with -O2.
% cat test.c
int main
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
We compiled two programs (A1.c, A2.c) by GCC-8.0.0 with -O3 option.
Though the two programs are equivalent, GCC outputs different assembly
tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
We compiled the following program by GCC-8.0.0 and GCC-7.0.1 with -O3 option.
GCC-7.0.1 performed better optimization than GCC-8.0.0.
$ cat test.c
void
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
GCC 7.0.1 for x86_64 miscompiles the following code.
Reproduces on gcc-4.6.4 or later with -O2, -O3 and -Os.
% cat test.c
int main (void)
{
volatile int a = 0;
int
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
GCC 7.0.1 for x86_64 miscompiles the following code.
% cat test.c
#define INT_MAX 0x7fff
#define INT_MIN (-INT_MAX-1)
int x;
int main (void)
{
volatile int a = 0
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
GCC 7.0.1 for x86_64 miscompiles the following code.
% cat test.c
int main (void)
{
volatile int a = 0;
long b = 2147483648L;
int c = a % 2
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
GCC 7.0.0 for x86_64 miscompiles the following code.
% cat test.c
int main (void)
{
int a = 2;
int b = 1;
int t = -1 * ( -0x4000 * a
tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
We compiled a program (A.c) by GCC-7.0.0 and clang-3.8.0 with -O3 option.
clang-3.8.0 performed better optimization than GCC-7.0.0.
(A.c)
#include
i
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
GCC 7.0.0 for x86_64 miscompiles the following code.
% cat test.c
volatile char buff = 0;
void PRINTF(const char* s)
{
while(*s++) buff = *s;
}
int a = 1;
int b
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
GCC 7.0.0 for x86_64 miscompiles the following code.
% cat test.c
int x = 0x4000;
int main (void)
{
int t = - 0x7FFF - ( -2 * x ) ;
if (t != 1
tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
We compiled a program (A.c) by GCC-7.0.0 and GCC-5.2.1 with -O3 option.
GCC-5.2.1 performed better optimization than GCC-7.0.0.
(A.c)
int main ()
{
vol
tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
We compiled a program (A.c) by GCC-7.0.0 and GCC-5.2.1 with -O3 option.
GCC-5.2.1 performed better optimization than GCC-7.0.0.
(A.c)
int x = 1;
int
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
GCC-6.0 for x86_64 miscompiles the following code.
$ cat test.c
#define INT_MIN ( -2147483647 - 1 )
int main (void)
{
int x0 = INT_MIN;
long x1 = 0L;
int x2
nt: c
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
We compiled a program (A.c) by GCC-5.2.1 and GCC-6.0.0 with -O3 option.
GCC-5.2.1 performed better optimization than GCC-6.0.0.
Note that "unsigned int" is 3
: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
GCC-6.0.0 miscompiles the following code.
$ cat error.c
int main(void){
volatile int a = -1;
long long b = -9223372036854775807LL-1; // LLONG_MIN
long long x = (a & b);
: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
GCC-6.0.0 miscompiles the following code.
GCC-4.3.6 or later versions miscompile too.
$cat error.c
int main(void) {
int a = -1;
static int b = -2147483647 - 1;
static int c
nt: c
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
We compiled a program (A.c) by GCC-5.1.0 and GCC-6.0.0 with -O3 option.
GCC-5.1.0 performed better optimization than GCC-6.0.0.
(A.c)
int main (void)
{
volatil
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67949
--- Comment #3 from Ishiura Lab Compiler Team ---
We are very sorry that somehow we failed to do final check with the latest
trunk before submitting the report.
tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
We compiled a program (A.c) by GCC-5.1.0 and GCC-6.0.0 with -O3 option.
GCC-5.1.0 performed better optimization than GCC-6.0.0.
(A.c)
#include
int x11
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target Milestone: ---
We compiled a program (A.c) by GCC-6.0.0 and LLVM/Clang-3.7.0 with -O3 option.
LLVM/Clang worked better on this test case, where the shift operation is
optimized out
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64992
--- Comment #4 from Ishiura Lab Compiler Team ---
FYI, clang-3.6 -O3 seems to do the same optimization on "org.c" as well as on
"opt.c."
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64992
--- Comment #3 from Ishiura Lab Compiler Team ---
Looking only from outside, the two programs are virtually equal, so we
just wondered what hinders the optimization on one of the programs.
The Optimization on "opt.c" seems very strong, so we th
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
The two programs (A.c) and (B.c) only differ by one line (marked by "//
<---HERE"),
where (B.c) simply replace local variable b by its initial value 2U.
The code (A.s) for
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61931
--- Comment #2 from Ishiura Lab Compiler Team ---
We are sorry for having reported an error program with undefined behavior.
We have redone minimization. The resulting program is as follows.
$ cat test.c
int a = 1;
int b = 0;
int c = 1;
int d =
: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
The two programs (A.c) and (B.c) only differ by one line
(marked by "// <---HERE"), where (B.c) change 0x1L to 0L.
Resulting codes by "x86_64-unk
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 4.9.2 for x86_64 miscompiles the following code with optimize option -Os.
$ cat error.c
unsigned int a = 0U;
int t = 0;
int main (void)
{
int b = 0;
volatile int c = 0;
long
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 5.0.0 for x86_64 miscompiles the following code.
$ cat test.c
int a = 0, b = 0, c = 0, d, e;
int
main (void)
{
d = ((20 % (1 != b)) && c) + 2147483647;
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 5.0.0 for x86_64 miscompiles the following code.
$ cat test.c
int a = 0, b = 1, c = 0, d = 1, e, f, g, h;
int
main ()
{
e = 1 >> d;
f = ((31 / (1 >
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 4.8.4 for arm miscompiles the following code.
$ cat test.c
int a, b, c, d, e, f, g, h;
long long i;
int
main (void)
{
int j;
i = a - b | ((1LL * c) >> 1)) / 3
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
We have two equvalent programs (A) and (B), which only differ by one line
(marked by "// <---HERE"), where (B) simply folds a+972195718 to 972195717,
for local variable a=-1.
R
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 4.10.0 ICEs on the following code. (x86_64)
$ cat test.c
int a, b, d;
int main (void)
{
int c = a && 1;
d = 1 << (((c | (b - 842)) << 1) + 1);
return 0;
}
$
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 4.4.7 - 4.10.0 for x86_64 miscompiles the following code.
$ cat test.c
int main (void)
{
long a = 0;
long b = 0x7FFFL;
int t = (a - 2) > (b
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 4.8 - 4.10 for i686 and x86_64 ICE the following code.
/*
$ x86_64-unknown-linux-gnu-gcc-4.10.0 test.c
x86_64-unknown-linux-gnu-gcc-4.10.0: internal compiler error:
Segmentation fault
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 4.7 - 4.10 for i686 and x86_64 miscompiles the following code.
$ cat error.c
#include
int x = 1;
main ()
{
unsigned long long t = 0xLLU
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 4.9.0 for x86_64 miscompiles the following code.
$ cat error.c
struct S0 { short m0; short m1; };
struct S1 { unsigned m0 : 1; char m1[2][2]; struct S0 m2[2]; };
struct S1 x = {1
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
Target: x86_64-pc-linux-gnu
GCC 4.9.0 ICEs on the following code. (x86_64)
$ cat test.c
int g0 = 1;
long g1 = 0;
int main (void)
{
int x0 = 1;
int x1 = 1
: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 4.9.0 ICEs on the following code. (i686 and x86_64)
$ cat error.c
int main (void)
{
int x = 0;
int y = 127 | ( 128 & ( 2 * x ));
return 0;
}
$ i686-pc-linux-gnu-gcc-4
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 4.7.2 - 4.9.0 for i686 and x86_64 miscompiles the following code.
$ cat error.c
int main (void)
{
volatile int k = 1;
int t = 2 | ( ( k - 1) >> 31 );
if (
Assignee: unassigned at gcc dot gnu.org
Reporter: ishiura-compiler at ml dot kwansei.ac.jp
GCC 4.8.2 for i686 miscompiles the following code.
$ cat error.c
int main (void)
{
int a = -1;
int b = 2147483647;
int c = 2;
int t = 1 - ((a - b) / c
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57209
Bug #: 57209
Summary: Wrong code of print statement
Classification: Unclassified
Product: gcc
Version: 4.8.1
Status: UNCONFIRMED
Severity: normal
Priority:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57131
Bug #: 57131
Summary: Wong register assignment?
Classification: Unclassified
Product: gcc
Version: 4.8.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57083
Bug #: 57083
Summary: Wrong constant folding
Classification: Unclassified
Product: gcc
Version: 4.8.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56984
Bug #: 56984
Summary: GCC-4.8.0 ICE in tree_vrp.c
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56899
Bug #: 56899
Summary: Wrong constant folding
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56250
--- Comment #3 from Ishiura Lab Compiler Team 2013-02-08 01:59:18 UTC ---
(In reply to comment #1)
> When I do this:
> unsigned x = 2;
> unsigned t = (x/2);
> unsigned t1 = -t;
> unsigned t2 = t2/2;
>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56250
Bug #: 56250
Summary: Wrong constant folding on unsigned int
Classification: Unclassified
Product: gcc
Version: 4.7.2
Status: UNCONFIRMED
Severity: normal
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