[Bug libgcc/67792] GCC 5.2 - make clean fails in libgcc
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67792 Alex Kruppa changed: What|Removed |Added CC||akruppa at gmail dot com --- Comment #4 from Alex Kruppa --- Problem still exists in 10.2.0: true "AR_FLAGS=" "CC_FOR_BUILD=" "CC_FOR_TARGET=" "CFLAGS=" "CXXFLAGS=" "CFLAGS_FOR_BUILD=" "CFLAGS_FOR_TARGET=" "INSTALL=/usr/bin/install -c" "INSTALL_DATA=/usr/bin/install -c -m 644" "INSTALL_PROGRAM=/usr/bin/install -c" "INSTALL_SCRIPT=/usr/bin/install -c" "LDFLAGS=" "LIBCFLAGS=" "LIBCFLAGS_FOR_TARGET=" "MAKE=make" "MAKEINFO=makeinfo --split-size=500 --split-size=500 " "SHELL=/bin/sh" "RUNTESTFLAGS=" "exec_prefix=/opt/gcc-10.2.0" "infodir=/opt/gcc-10.2.0/share/info" "libdir=/opt/gcc-10.2.0/lib64" "includedir=/opt/gcc-10.2.0/include" "prefix=/opt/gcc-10.2.0" "tooldir=" "gxx_include_dir=/opt/gcc-10.2.0/include/c++/10.2.0" "AR=" "AS=/./gcc/as" "LD=/./gcc/collect-ld" "RANLIB=" "NM=/./gcc/nm" "NM_FOR_BUILD=" "NM_FOR_TARGET=" "DESTDIR=" "WERROR=" DO=mostlyclean multi-clean # make make[5]: Leaving directory '/home/alex/build/gcc-10.2.0/x86_64-pc-linux-gnu/32/libstdc++-v3' make[4]: Leaving directory '/home/alex/build/gcc-10.2.0/x86_64-pc-linux-gnu/32/libstdc++-v3' make[3]: Leaving directory '/home/alex/build/gcc-10.2.0/x86_64-pc-linux-gnu/libstdc++-v3' make[2]: Leaving directory '/home/alex/build/gcc-10.2.0/x86_64-pc-linux-gnu/libstdc++-v3' make[1]: Leaving directory '/home/alex/build/gcc-10.2.0/x86_64-pc-linux-gnu/libstdc++-v3' make[1]: Entering directory '/home/alex/build/gcc-10.2.0/x86_64-pc-linux-gnu/libgcc' make[1]: -B/opt/gcc-10.2.0/x86_64-pc-linux-gnu/bin/: Command not found make[1]: -B/opt/gcc-10.2.0/x86_64-pc-linux-gnu/bin/: Command not found /bin/sh: line 0: test: !=: unary operator expected rm -f libgcc_tm.h libgcc.map Makefile:187: *** Recursive variable 'AR_FOR_TARGET' references itself (eventually). Stop. make[1]: Leaving directory '/home/alex/build/gcc-10.2.0/x86_64-pc-linux-gnu/libgcc' make: *** [Makefile:19194: clean-stage1-target-libgcc] Error 2
[Bug tree-optimization/60641] New: Converting ushort to offset on x86_64 generates double movzwl
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60641
Bug ID: 60641
Summary: Converting ushort to offset on x86_64 generates double
movzwl
Product: gcc
Version: 4.7.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: akruppa at gmail dot com
The following test cases produce sub-optimal assembly output.
This was verified with these three versions of gcc:
gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3
gcc (SUSE Linux) 4.7.3
gcc (Debian 4.8.2-16) 4.8.2
#include
unsigned short
foo (const unsigned short *start, const unsigned char *mask)
{
unsigned short r = 0;
unsigned short ux = *start;
if (mask[ux])
r = ux;
return r;
}
void bar(unsigned int *s, unsigned short a)
{
s[a] = a;
}
Compile with, e.g.,
gcc -std=c99 -g -W -Wall -O3 -c movzwl.c
The effect also occurs when using -O2 instead.
The foo() function contains:
0x <+0>: movzwl (%rdi),%edx
0x0003 <+3>: xor%eax,%eax
0x0005 <+5>: movzwl %dx,%ecx
0x0008 <+8>: cmpb $0x0,(%rsi,%rcx,1)
The foo() function is:
0x0010 <+0>: movzwl %si,%eax
0x0013 <+3>: movzwl %si,%esi
0x0016 <+6>: mov%esi,(%rdi,%rax,4)
0x0019 <+9>: retq
In both cases, an unnecessary movzwl instruction is generated. This may be the
same issue as #36873, which was rejected because the test cases used volatile
accesses. These test cases here show that the duplicate movzwl occurs without
volatile as well.
[Bug tree-optimization/61277] New: Incorrect -Warray-bounds warning with 4.9.0
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61277
Bug ID: 61277
Summary: Incorrect -Warray-bounds warning with 4.9.0
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: akruppa at gmail dot com
The following code, when compiled with the gcc 4.9.0 release or with SVN branch
gcc-4_9-branch r210719, via
gcc -O2 -Wall -c bug.c
produces the warning
bug.c: In function ‘foo’:
bug.c:13:8: warning: array subscript is below array bounds [-Warray-bounds]
if (s[n-1] != 2)
^
If foo() returns 2, the array accesses are not out of bounds.
Gcc 4.8.1 does not produce the warning.
The gcc 4.9.0 and SVN builds were configured with
configure --prefix=install/dir/ --enable-languages=c,c++
int foo();
int s[2];
int bar()
{
int n = foo();
int i;
for(i = 0 ; i < n ; i++)
if ((i == 0) != (s[i] == 0))
return 0;
if (s[n-1] != 2)
return 0;
for(i = 0 ; i < n ; i++)
if (s[0])
return 0;
return 1;
}
[Bug target/60641] Converting ushort to offset on x86_64 generates double movzwl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60641 --- Comment #2 from Alex Kruppa --- With gcc-4.9.0, compiled from the official tarball, the foo() function does NOT produce the double movzwl instruction any more, but the bar() function still does. Dump of assembler code for function foo: 0x <+0>:movzwl (%rdi),%edx 0x0003 <+3>:cmpb $0x0,(%rsi,%rdx,1) 0x0007 <+7>:mov%rdx,%rax 0x000a <+10>:mov$0x0,%edx 0x000f <+15>:cmove %edx,%eax 0x0012 <+18>:retq Dump of assembler code for function bar: 0x0020 <+0>:movzwl %si,%eax 0x0023 <+3>:movzwl %si,%esi 0x0026 <+6>:mov%esi,(%rdi,%rax,4) 0x0029 <+9>:retq
