[PATCH] D97360: [TTI] Consider select form of and/or i1 as having arithmetic cost

[Juneyoung Lee via Phabricator via llvm-commits]

aqjune added a comment.

In D97360#2594315 <https://reviews.llvm.org/D97360#2594315>, @spatel wrote:

> Thanks - IIUC, we're also going to need to some codegen changes to avoid regressions. For example (the icmps are to avoid diffs due to lack of signext/zeroext specifiers on parameters with vector type):
>
>   define <4 x i1> @b(<4 x i32> %x, <4 x i32> %y) {
>     %c1 = icmp eq <4 x i32> %x, <i32 42, i32 42, i32 42, i32 42>
>     %c2 = icmp sgt <4 x i32> %y, <i32 42, i32 42, i32 42, i32 42>
>     %s = select <4 x i1> %c1, <4 x i1> <i1 true, i1 true, i1 true, i1 true>, <4 x i1> %c2
>     ret <4 x i1> %s
>   }
>   define <4 x i1> @b2(<4 x i32> %x, <4 x i32> %y) {
>     %c1 = icmp eq <4 x i32> %x, <i32 42, i32 42, i32 42, i32 42>
>     %c2 = icmp sgt <4 x i32> %y, <i32 42, i32 42, i32 42, i32 42>
>     %s = or <4 x i1> %c1, %c2
>     ret <4 x i1> %s
>   }
>
>
>
>   $ llc -o - logical.ll -mattr=avx -mtriple=x86_64--
>   _b:                                     ## @b
>   	vmovdqa	LCPI2_0(%rip), %xmm2            ## xmm2 = [42,42,42,42]
>   	vpcmpeqd	%xmm2, %xmm0, %xmm0
>   	vpcmpgtd	%xmm2, %xmm1, %xmm1
>   	vblendvps	%xmm0, LCPI2_1(%rip), %xmm1, %xmm0
>   	retq
>   _b2:                                    ## @b2
>   	vmovdqa	LCPI3_0(%rip), %xmm2            ## xmm2 = [42,42,42,42]
>   	vpcmpeqd	%xmm2, %xmm0, %xmm0
>   	vpcmpgtd	%xmm2, %xmm1, %xmm1
>   	vpor	%xmm1, %xmm0, %xmm0
>   	retq

Thank you for the info..!
I'll check whether regression happens with different targets as well and make patches if any.

select form of and/or operations are eagerly folded by InstCombine currently, so they'll look good hopefully.


Repository:
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