Hi Segher,
Yes, the old committed patch caused it matches two insns.
So I submitted the new patch which fixes the problem. Here is
the new patch.
https://gcc.gnu.org/pipermail/gcc-patches/2022-February/590958.html
The new pattern is:
/* { dg-final { scan-rtl-dump-times {\(compare:CC \(and:SI \(subreg:SI
\(reg:DI} 1 "combine" } } */
I tested it and it is fine on all sub-targets.
Thanks.
On 20/4/2022 上午 5:06, Segher Boessenkool wrote:
> On Tue, Apr 19, 2022 at 04:05:06PM +0800, HAO CHEN GUI wrote:
>> I tested the test case on Linux and AIX with both big and little endian.
>> The test case requires lp64 target, so it won't be tested on 32-bit targets.
>>
>> On big endian (both AIX and Linux), it should match
>> (compare:CC (and:SI (subreg:SI (reg:DI 207) 4)
>>
>> On little endian (both AIX and Linux), it should match
>> (compare:CC (and:SI (subreg:SI (reg:DI 207) 0)
>>
>> So, the pattern in my patch should work fine.
>>
>> /* { dg-final { scan-rtl-dump-times {\(compare:CC \(and:SI \(subreg:SI
>> \(reg:DI} 1 "combine" } } */
>
> On powerpc64-linux:
>
> FAIL: gcc.target/powerpc/pr56605.c scan-rtl-dump-times combine "\\(compare:CC
> \\((?:and|zero_extend):(?:[SD]I) \\((?:sub)?reg:[SD]I" 1
>
> It matches twice instead of once, namely:
>
> (insn 19 18 20 2 (parallel [
> (set (reg:CC 208)
> (compare:CC (and:SI (subreg:SI (reg:DI 207) 4)
> (const_int 3 [0x3]))
> (const_int 0 [0])))
> (set (reg:SI 129 [ prolog_loop_niters.5 ])
> (and:SI (subreg:SI (reg:DI 207) 4)
> (const_int 3 [0x3])))
> ]) 208 {*andsi3_imm_mask_dot2}
> (nil))
>
> (insn 81 80 82 11 (parallel [
> (set (reg:CC 232)
> (compare:CC (and:DI (subreg:DI (reg:SI 136 [ niters.6 ]) 0)
> (const_int 7 [0x7]))
> (const_int 0 [0])))
> (clobber (scratch:DI))
> ]) 207 {*anddi3_imm_mask_dot}
> (expr_list:REG_DEAD (reg:SI 136 [ niters.6 ])
> (nil)))
>
> The paradoxical subreg in the latter wasn't expected :-)
>
>
> Segher
