Package: gcc-3.0
Version: 1:3.0-0pre010427
Severity: wishlist
Here's another segment that needs to have an assembler optimiser run over it:
int foo(char c) {
if (c && !(c & 0x80)) {
a();
} else {
b();
}
}
produces with -O2:
0: 55 push %ebp
1: 89 e5 mov %esp,%ebp
3: 83 ec 08 sub $0x8,%esp
6: 8a 45 08 mov 0x8(%ebp),%al
9: 84 c0 test %al,%al
b: 74 04 je 11 <foo+0x11>
d: 84 c0 test %al,%al
f: 79 07 jns 18 <foo+0x18>
9-f can be rewritten as:
test %al, %al
jg 18
11: e8 fc ff ff ff call 12 <foo+0x12>
12: R_386_PC32 b
16: c9 leave
17: c3 ret
18: e8 fc ff ff ff call 19 <foo+0x19>
19: R_386_PC32 a
1d: eb f7 jmp 16 <foo+0x16>
And what purpose does this jmp serve? Surely it can be replaced with
leave
ret
1f: 90 nop
-- System Information
Debian Release: testing/unstable
Kernel Version: Linux gondolin 2.4.6-686-smp #1 SMP Thu Jul 5 22:06:27 EST 2001
i686 unknown
Versions of the packages gcc-3.0 depends on:
ii binutils 2.11.90.0.7-2 The GNU assembler, linker and binary utiliti
ii cpp-3.0 3.0-0pre010403 The GNU C preprocessor.
ii gcc-3.0-base 3.0-0pre010403 The GNU compiler collection (base package).
ii libc6 2.2.3-5 GNU C Library: Shared libraries and Timezone
ii libgcc0 3.0-0pre010427 Shared libgcc.
