On 03/17/2011 11:20 AM, McCall, Ronald SIK wrote:
If you let us in on what exactly the secret differences were, it would
be easier to opine on this topic.
Sure thing! Here is an instruction sequence from the original Solaris
toolchain:
Resending to gcc@. I didn't really want a private message about it.
fe000230: 54 6a 87 be rlwinm r10,r3,16,30,31
fe000234: 65 49 ff ff oris r9,r10,65535
fe000238: 61 28 ff fc ori r8,r9,65532
fe00023c: 6d 07 80 00 xoris r7,r8,32768
fe000240: 3c 00 43 30 lis r0,17200
fe000244: 90 e1 00 0c stw r7,12(r1)
fe000248: 90 01 00 08 stw r0,8(r1)
fe00024c: 3c 80 fe 14 lis r4,-492
fe000250: c8 01 00 08 lfd f0,8(r1)
fe000254: 39 24 82 38 addi r9,r4,-32200<<< Instruction sequence #1
fe000258: c8 89 00 00 lfd f4,0(r9)<<< (continued)
fe00025c: 74 60 00 08 andis. r0,r3,8
fe000260: 3c c0 00 01 lis r6,1
fe000264: fc 60 20 28 fsub f3,f0,f4<<< Instruction sequence #2
fe000268: fc 40 18 18 frsp f2,f3
fe00026c: fc 20 10 90 fmr f1,f2
fe000270: fc 00 08 1e fctiwz f0,f1
fe000274: d8 01 00 10 stfd f0,16(r1)
fe000278: 80 81 00 14 lwz r4,20(r1)
fe00027c: 98 86 8f 0d stb r4,-28915(r6)
fe000280: 41 82 00 cc beq- fe00034c
Here is the same instruction sequence from the newly built Linux toolchain:
fe000230: 54 6a 87 be rlwinm r10,r3,16,30,31
fe000234: 65 49 ff ff oris r9,r10,65535
fe000238: 61 28 ff fc ori r8,r9,65532
fe00023c: 6d 07 80 00 xoris r7,r8,32768
fe000240: 3c 00 43 30 lis r0,17200
fe000244: 90 e1 00 0c stw r7,12(r1)
fe000248: 90 01 00 08 stw r0,8(r1)
fe00024c: 3c 80 fe 14 lis r4,-492
fe000250: c8 01 00 08 lfd f0,8(r1)
fe000254: c9 a4 87 b0 lfd f13,-30800(r4)<<< Instruction sequence #1
fe000258: fc 60 68 28 fsub f3,f0,f13<<< Instruction sequence #2
fe00025c: 74 60 00 08 andis. r0,r3,8
fe000260: 3c 80 00 01 lis r4,1
fe000264: fc 40 18 18 frsp f2,f3
fe000268: fc 20 10 90 fmr f1,f2
fe00026c: fc 00 08 1e fctiwz f0,f1
fe000270: d8 01 00 10 stfd f0,16(r1)
fe000274: 80 e1 00 14 lwz r7,20(r1)
fe000278: 98 e4 8f 0d stb r7,-28915(r4)
fe00027c: 41 82 00 c8 beq- fe000344
Instruction sequence #1 has been combined into a single equivalent instruction.
Instruction sequence #2 moved. Register usage is also different but
equivalent.
Ron McCall
