Two C file (p.c and q.c) attached bellows. With an inline assembly
line (even just a comment), the code sequence is different. As a
result, the function foo() in q.c is working OK but not the foo()
in p.c.
*** Command line ***
$ /utils/gcc/3.4.3/mipsel-linux-uclibc/i386/bin/mipsel-linux-gcc -v
Reading specs from
/utils/gcc/3.4.3/mipsel-linux-uclibc/i386/lib/gcc/mipsel-linux-uclibc/3.4.3/specs
Configured with:
/home/YH/MIPS/BR/buildroot/toolchain_build_mipsel/gcc-3.4.3/configure
--prefix=/utils/gcc/3.4.3/mipsel-linux-uclibc/i386 --build=i386-pc-linux-gnu
--host=i386-pc-linux-gnu --target=mipsel-linux-uclibc --enable-languages=c,c++
--enable-shared --disable-__cxa_atexit --enable-target-optspace --with-gnu-ld
--disable-nls --enable-multilib --enable-sjlj-exceptions
Thread model: posix
gcc version 3.4.3
$ /utils/gcc/3.4.3/mipsel-linux-uclibc/i386/bin/mipsel-linux-gcc -mno-abicalls
-O2 -c -o p.o p.c
$ /utils/gcc/3.4.3/mipsel-linux-uclibc/i386/bin/mipsel-linux-objdump -S p.o >
p.dasm
$ /utils/gcc/3.4.3/mipsel-linux-uclibc/i386/bin/mipsel-linux-gcc -mno-abicalls
-O2 -c -o q.o q.c
$ /utils/gcc/3.4.3/mipsel-linux-uclibc/i386/bin/mipsel-linux-objdump -S q.o >
q.dasm
==== p.c ====
int foo(int x, int y, int z)
{
__asm__ __volatile__ ("/* TEST */\n");
return((x + y) / z);
}
==== end of p.c ====
==== q.c ====
int foo(int x, int y, int z)
{
// __asm__ __volatile__ ("/* TEST */\n");
return((x + y) / z);
}
==== end of q.c ====
====> with the inline assembly (p.dasm)
p.o: file format elf32-tradlittlemips
Disassembly of section .text:
00000000 <foo>:
0: 00851021 addu v0,a0,a1
4: 14c00002 bnez a2,10 <foo+0x10>
8: 0046001a div zero,v0,a2
c: 0007000d break 0x7
10: 00001012 mflo v0
14: 03e00008 jr ra
18: 00000000 nop
1c: 00000000 nop
====> without the inline assembly (q.dasm)
q.o: file format elf32-tradlittlemips
Disassembly of section .text:
00000000 <foo>:
0: 00851021 addu v0,a0,a1
4: 0046001a div zero,v0,a2
8: 14c00002 bnez a2,14 <foo+0x14>
c: 00000000 nop
10: 0007000d break 0x7
14: 00001012 mflo v0
18: 03e00008 jr ra
1c: 00000000 nop
----> assembly file (p.s)
.file 1 "p.c"
.section .mdebug.abi32
.previous
.text
.align 2
.globl foo
.ent foo
.type foo, @function
foo:
.frame $sp,0,$31 # vars= 0, regs= 0/0, args= 0, gp= 0
.mask 0x00000000,0
.fmask 0x00000000,0
#APP
/* TEST */
#NO_APP
addu $2,$4,$5
div $0,$2,$6
bne $6,$0,1f
break 7
1:
mflo $2
j $31
.end foo
.ident "GCC: (GNU) 3.4.3"
----> assembly file (q.s)
.file 1 "q.c"
.section .mdebug.abi32
.previous
.text
.align 2
.globl foo
.ent foo
.type foo, @function
foo:
.frame $sp,0,$31 # vars= 0, regs= 0/0, args= 0, gp= 0
.mask 0x00000000,0
.fmask 0x00000000,0
.set noreorder
.set nomacro
addu $2,$4,$5
div $0,$2,$6
bne $6,$0,1f
nop
break 7
1:
mflo $2
j $31
nop
.set macro
.set reorder
.end foo
.ident "GCC: (GNU) 3.4.3"
--
Summary: Empty inline assembly cause the generated code to be
wrong?
Product: gcc
Version: 3.4.3
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: yhlin at sdesigns dot com
CC: gcc-bugs at gcc dot gnu dot org,yhlin at sdesigns dot
com
GCC build triplet: i686-pc-linux
GCC host triplet: i686-pc-linux
GCC target triplet: mipsel-linux-gcc
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21535
