[llvm] [X86] Try Folding icmp of v8i32 -> fcmp of v8f32 on AVX (PR #82290)

[Simon Pilgrim via llvm-commits]

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@@ -10,10 +10,11 @@
 define <8 x i16> @pr25080(<8 x i32> %a) {
 ; AVX1-LABEL: pr25080:
 ; AVX1:       # %bb.0: # %entry
+; AVX1-NEXT:    vandps {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm0, %ymm0
+; AVX1-NEXT:    vcvtdq2ps %ymm0, %ymm0
 ; AVX1-NEXT:    vextractf128 $1, %ymm0, %xmm0
-; AVX1-NEXT:    vpand {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0, %xmm0
-; AVX1-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX1-NEXT:    vpcmpeqd %xmm1, %xmm0, %xmm0
+; AVX1-NEXT:    vxorps %xmm1, %xmm1, %xmm1
+; AVX1-NEXT:    vcmpeqps %xmm1, %xmm0, %xmm0
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RKSimon wrote:

Still not perfect, but I'm not sure how much more we should try to do.

Maybe worth folding `extract_subvector(sint_to_fp())` -> `sint_to_fp(extract_subvector())`, but not sure if we should bother folding the vcmpeqps back to vpcmpeq again....

https://github.com/llvm/llvm-project/pull/82290