[PATCH][AVX512] Broken icmp for <16 x i64>.

Bader, Aleksey A aleksey.a.bader at intel.com
Sun Dec 15 03:34:57 PST 2013

Nice catch. Thanks.
Patch updated.

From: Demikhovsky, Elena
Sent: Sunday, December 15, 2013 1:32 PM
To: Bader, Aleksey A; llvm-commits at cs.uiuc.edu
Subject: RE: [PATCH][AVX512] Broken icmp for <16 x i64>.

+def : Pat<(v16i1 (concat_vectors (v8i1 VK8:$src1), (v8i1 VK8:$src2))),
+          (v16i1 (KUNPCKBWrr (COPY_TO_REGCLASS VK8:$src1, VK16), (COPY_TO_REGCLASS VK8:$src2, VK16)))>;
I think you should switch src1 and src2 because according to the spec
DEST[7:0] <-- SRC2[7:0]
DEST[15:8] <-- SRC1[7:0]

-           Elena

From: Bader, Aleksey A
Sent: Friday, December 13, 2013 17:45
To: llvm-commits at cs.uiuc.edu<mailto:llvm-commits at cs.uiuc.edu>
Cc: Demikhovsky, Elena
Subject: [PATCH][AVX512] Broken icmp for <16 x i64>.


This patch fixes the following test on AVX512:
define <16 x i1> @test1(<16 x i64> %a, <16 x i64> %b) nounwind {
  %res = icmp eq <16 x i64> %a, %b
  ret <16 x i1> %res

Currently llc produces

        vpcmpeqq        %zmm3, %zmm1, %k0
        kmovw   %k0, (%rsp)
        vpcmpeqq        %zmm2, %zmm0, %k0
        kmovw   %k0, (%rsp)
       kmovw   (%rsp), %k0
        kmovw   %k0, (%rdi)


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