Optimization failure

[Kai Henningsen <kai at khms dot westfalen dot de>]

The following example code demonstrates a problem with the optimizer:
Only the first range of constants is recognized.

I hope this is enough information, but if you need more, just ask :-)

Source (generated by a script, otherwise I would already have hand-optimized
it):

int is_control(int c)
{
	return c == 0x0000 || c == 0x0001 || c == 0x0002 || c == 0x0003
	    || c == 0x0004 || c == 0x0005 || c == 0x0006 || c == 0x0007
	    || c == 0x0008 || c == 0x0009 || c == 0x000A || c == 0x000B
	    || c == 0x000C || c == 0x000D || c == 0x000E || c == 0x000F
	    || c == 0x0010 || c == 0x0011 || c == 0x0012 || c == 0x0013
	    || c == 0x0014 || c == 0x0015 || c == 0x0016 || c == 0x0017
	    || c == 0x0018 || c == 0x0019 || c == 0x001A || c == 0x001B
	    || c == 0x001C || c == 0x001D || c == 0x001E || c == 0x001F
	    || c == 0x007F || c == 0x0080 || c == 0x0081 || c == 0x0082
	    || c == 0x0083 || c == 0x0084 || c == 0x0085 || c == 0x0086
	    || c == 0x0087 || c == 0x0088 || c == 0x0089 || c == 0x008A
	    || c == 0x008B || c == 0x008C || c == 0x008D || c == 0x008E
	    || c == 0x008F || c == 0x0090 || c == 0x0091 || c == 0x0092
	    || c == 0x0093 || c == 0x0094 || c == 0x0095 || c == 0x0096
	    || c == 0x0097 || c == 0x0098 || c == 0x0099 || c == 0x009A
	    || c == 0x009B || c == 0x009C || c == 0x009D || c == 0x009E
	    || c == 0x009F || c == 0x200C || c == 0x200D || c == 0x200E
	    || c == 0x200F || c == 0x202A || c == 0x202B || c == 0x202C
	    || c == 0x202D || c == 0x202E || c == 0x206A || c == 0x206B
	    || c == 0x206C || c == 0x206D || c == 0x206E || c == 0x206F
	    || c == 0xFEFF;
}

Compiler invocation:

Script started on Sun Feb 28 11:10:49 1999
kai@khms tty5 ~/mimetext $ egcc -v -O9 -S bug.c
Reading specs from /usr/lib/gcc-lib/i486-linux/egcs-2.91.60/specs
gcc version egcs-2.91.60 Debian 2.1 (egcs-1.1.1 release)
 /usr/lib/gcc-lib/i486-linux/egcs-2.91.60/cpp -lang-c -v -undef -D__GNUC__=2 -D__GNUC_MINOR__=91 -D__ELF__ -Dunix -Di386 -D__i386__ -Dlinux -D__ELF__ -D__unix__ -D__i386__ -D__i386__ -D__linux__ -D__unix -D__i386 -D__linux -Asystem(posix) -D__OPTIMIZE__ -Asystem(unix) -Acpu(i386) -Amachine(i386) -Di386 -D__i386 -D__i386__ -Di486 -D__i486 -D__i486__ bug.c /tmp/cch8cSfx.i
GNU CPP version egcs-2.91.60 Debian 2.1 (egcs-1.1.1 release) (i386 Linux/ELF)
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include
 /usr/lib/gcc-lib/i486-linux/egcs-2.91.60/include
 /usr/include
End of search list.
 /usr/lib/gcc-lib/i486-linux/egcs-2.91.60/cc1 /tmp/cch8cSfx.i -quiet -dumpbase bug.c -O9 -version -o bug.s
GNU C version egcs-2.91.60 Debian 2.1 (egcs-1.1.1 release) (i486-linux) compiled by GNU C version egcs-2.91.60 Debian 2.1 (egcs-1.1.1 release).
kai@khms tty5 ~/mimetext $ exit

Script done on Sun Feb 28 11:11:10 1999

Assembler output:

	.file	"bug.c"
	.version	"01.01"
gcc2_compiled.:
.text
	.align 16
.globl is_control
	.type	 is_control,@function
is_control:
	pushl %ebp
	movl %esp,%ebp
	xorl %eax,%eax
	movl 8(%ebp),%edx
	cmpl $31,%edx
	jbe .L3
	cmpl $127,%edx
	je .L3
	cmpl $128,%edx
	je .L3
	cmpl $129,%edx
	je .L3
	cmpl $130,%edx
	je .L3
	cmpl $131,%edx
	je .L3
	cmpl $132,%edx
	je .L3
	cmpl $133,%edx
	je .L3
	cmpl $134,%edx
	je .L3
	cmpl $135,%edx
	je .L3
	cmpl $136,%edx
	je .L3
	cmpl $137,%edx
	je .L3
	cmpl $138,%edx
	je .L3
	cmpl $139,%edx
	je .L3
	cmpl $140,%edx
	je .L3
	cmpl $141,%edx
	je .L3
	cmpl $142,%edx
	je .L3
	cmpl $143,%edx
	je .L3
	cmpl $144,%edx
	je .L3
	cmpl $145,%edx
	je .L3
	cmpl $146,%edx
	je .L3
	cmpl $147,%edx
	je .L3
	cmpl $148,%edx
	je .L3
	cmpl $149,%edx
	je .L3
	cmpl $150,%edx
	je .L3
	cmpl $151,%edx
	je .L3
	cmpl $152,%edx
	je .L3
	cmpl $153,%edx
	je .L3
	cmpl $154,%edx
	je .L3
	cmpl $155,%edx
	je .L3
	cmpl $156,%edx
	je .L3
	cmpl $157,%edx
	je .L3
	cmpl $158,%edx
	je .L3
	cmpl $159,%edx
	je .L3
	cmpl $8204,%edx
	je .L3
	cmpl $8205,%edx
	je .L3
	cmpl $8206,%edx
	je .L3
	cmpl $8207,%edx
	je .L3
	cmpl $8234,%edx
	je .L3
	cmpl $8235,%edx
	je .L3
	cmpl $8236,%edx
	je .L3
	cmpl $8237,%edx
	je .L3
	cmpl $8238,%edx
	je .L3
	cmpl $8298,%edx
	je .L3
	cmpl $8299,%edx
	je .L3
	cmpl $8300,%edx
	je .L3
	cmpl $8301,%edx
	je .L3
	cmpl $8302,%edx
	je .L3
	cmpl $8303,%edx
	je .L3
	cmpl $65279,%edx
	jne .L2
.L3:
	movl $1,%eax
.L2:
	movl %ebp,%esp
	popl %ebp
	ret
.Lfe1:
	.size	 is_control,.Lfe1-is_control
	.ident	"GCC: (GNU) egcs-2.91.60 Debian 2.1 (egcs-1.1.1 release)"