[X86][TTI] Costmodel for AVX512DQ's VPMOVM2[DQ] / VPMOV[DQ]2M instructions

[lebedev.ri]

Summary

Much like the VPMOVM2[BW] / VPMOV[BW]2M from AVX512BW,
these either sign-extent the mask register into a vector,
or pack the mask from vector register.

Apparently, we didn't even have MCA tests for these,
added in rG2f364f6f0d3a2420ca78cbd80abb186657180e05,
so i'm just guessing that their perf characteristics
are optimal.

[tschuett]

I remember that there was a discussion using tablegen and the scheduling models to create these cost models. The discussion stoped. Having one diff per instruction does not scale.

[lebedev.ri]

In D114314#3144546, @tschuett wrote:

I remember that there was a discussion using tablegen and the scheduling models to create these cost models. The discussion stoped. Having one diff per instruction does not scale.

Yep.

[RKSimon]

In D114314#3144547, @lebedev.ri wrote:

In D114314#3144546, @tschuett wrote:

I remember that there was a discussion using tablegen and the scheduling models to create these cost models. The discussion stoped. Having one diff per instruction does not scale.

Yep.

Its even worse than that - the cost tables ignore many hw specific facts such that some ops can be run on multiple pipes (so a throughput cost of 1 might actually be 1/4 of that.....), and that usually we want accumulative costs of an entire code sequence, which the InstructionCost class can't do as it'd have to internally track some kind of llvm-mca like state. I've tried to work on stop gap solutions such as D46276 and D103695, but they rely on high quality scheduler models, which we just don't have yet (although D103695 has proved to be useful to iteratively fix the models as well as the cost tables).

So, first step would be to ensure we have decent scheduler models for all relevant x86 cpus, but there's many steps after that :(

[tschuett]

As an outsider, maybe have a document and discussion of the long-term goal, the necessary steps to get there, and document the problems of the current approach.

[tschuett]

You say instruction sequence. I would see it as a window. What is the cost of this instruction with a window of size k, i.e., k/2 instructions before and k/2 instructions after? If you increase accuracy, then costs would rise.

[lebedev.ri]

NFC, precommitted some more tests - i've completely neglected VL/+prefer-256-bit side of things apparently,
but that is for a followup commit.

[lebedev.ri]

Now with actual +VL support :(

[lebedev.ri]

Fix really dumb think-o - trunc cost is obviously 2, not 1 - https://godbolt.org/z/1TeYMjWE7 - trunc keeps lowest bit, while VPMOV.2M keeps the highest bit.

[RKSimon]

LGTM

[lebedev.ri]

In D114314#3145836, @RKSimon wrote:

LGTM

Thank you for the review!

llvm/lib/Target/X86/X86TargetTransformInfo.cpp

static const TypeConversionCostTblEntry AVX512BWConversionTbl[] {
     { ISD::TRUNCATE,    MVT::v16i1,  MVT::v16i16, 2 }, // widen to zmm
     { ISD::TRUNCATE,    MVT::v32i1,  MVT::v32i8,  2 }, // widen to zmm
     { ISD::TRUNCATE,    MVT::v32i1,  MVT::v32i16, 2 },
     { ISD::TRUNCATE,    MVT::v64i1,  MVT::v32i16, 2 },
     { ISD::TRUNCATE,    MVT::v64i1,  MVT::v64i8,  2 },
   };
 
   static const TypeConversionCostTblEntry AVX512DQConversionTbl[] = {
+    // Mask sign extend has an instruction.
+    { ISD::SIGN_EXTEND, MVT::v2i64,  MVT::v2i1,   1 },
+    { ISD::SIGN_EXTEND, MVT::v4i32,  MVT::v2i1,   1 },
+    { ISD::SIGN_EXTEND, MVT::v4i32,  MVT::v4i1,   1 },
+    { ISD::SIGN_EXTEND, MVT::v4i64,  MVT::v4i1,   1 },
+    { ISD::SIGN_EXTEND, MVT::v8i32,  MVT::v8i1,   1 },
+    { ISD::SIGN_EXTEND, MVT::v8i64,  MVT::v8i1,   1 },
+    { ISD::SIGN_EXTEND, MVT::v8i64,  MVT::v16i1,  1 },
+    { ISD::SIGN_EXTEND, MVT::v16i32, MVT::v16i1,  1 },
+
+    // Mask zero extend is a sext + shift.
+    { ISD::ZERO_EXTEND, MVT::v2i64,  MVT::v2i1,   2 },
+    { ISD::ZERO_EXTEND, MVT::v4i32,  MVT::v2i1,   2 },
+    { ISD::ZERO_EXTEND, MVT::v4i32,  MVT::v4i1,   2 },
+    { ISD::ZERO_EXTEND, MVT::v4i64,  MVT::v4i1,   2 },
+    { ISD::ZERO_EXTEND, MVT::v8i32,  MVT::v8i1,   2 },
+    { ISD::ZERO_EXTEND, MVT::v8i64,  MVT::v8i1,   2 },
+    { ISD::ZERO_EXTEND, MVT::v8i64,  MVT::v16i1,  2 },
+    { ISD::ZERO_EXTEND, MVT::v16i32, MVT::v16i1,  2 },
+
+    { ISD::TRUNCATE,    MVT::v2i1,   MVT::v2i64,  1 },
+    { ISD::TRUNCATE,    MVT::v2i1,   MVT::v4i32,  1 },
+    { ISD::TRUNCATE,    MVT::v4i1,   MVT::v4i32,  1 },
+    { ISD::TRUNCATE,    MVT::v4i1,   MVT::v4i64,  1 },
+    { ISD::TRUNCATE,    MVT::v8i1,   MVT::v8i32,  1 },
+    { ISD::TRUNCATE,    MVT::v8i1,   MVT::v8i64,  1 },
+    { ISD::TRUNCATE,    MVT::v16i1,  MVT::v16i32, 1 },
+    { ISD::TRUNCATE,    MVT::v16i1,  MVT::v8i64,  1 },
+
     { ISD::SINT_TO_FP,  MVT::v8f32,  MVT::v8i64,  1 },
     { ISD::SINT_TO_FP,  MVT::v8f64,  MVT::v8i64,  1 },
 
     { ISD::UINT_TO_FP,  MVT::v8f32,  MVT::v8i64,  1 },
     { ISD::UINT_TO_FP,  MVT::v8f64,  MVT::v8i64,  1 },
 
     { ISD::FP_TO_SINT,  MVT::v8i64,  MVT::v8f32,  1 },
     { ISD::FP_TO_SINT,  MVT::v8i64,  MVT::v8f64,  1 },

llvm/test/Analysis/CostModel/X86/cast.ll

 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %C = trunc <4 x i32> undef to <4 x i1>
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %D = zext <8 x i1> undef to <8 x i32>
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %E = sext <8 x i1> undef to <8 x i32>
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %F = trunc <8 x i32> undef to <8 x i1>
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %G = zext i1 undef to i32
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %H = trunc i32 undef to i1
 ; AVX2-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
 ;
-; AVX512-LABEL: 'add'
-; AVX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %A = zext <4 x i1> undef to <4 x i32>
-; AVX512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %B = sext <4 x i1> undef to <4 x i32>
-; AVX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %C = trunc <4 x i32> undef to <4 x i1>
-; AVX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %D = zext <8 x i1> undef to <8 x i32>
-; AVX512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %E = sext <8 x i1> undef to <8 x i32>
-; AVX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %F = trunc <8 x i32> undef to <8 x i1>
-; AVX512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %G = zext i1 undef to i32
-; AVX512-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %H = trunc i32 undef to i1
-; AVX512-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
+; AVX512F-LABEL: 'add'
+; AVX512F-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %A = zext <4 x i1> undef to <4 x i32>
+; AVX512F-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %B = sext <4 x i1> undef to <4 x i32>
+; AVX512F-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %C = trunc <4 x i32> undef to <4 x i1>
+; AVX512F-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %D = zext <8 x i1> undef to <8 x i32>
+; AVX512F-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %E = sext <8 x i1> undef to <8 x i32>
+; AVX512F-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %F = trunc <8 x i32> undef to <8 x i1>
+; AVX512F-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %G = zext i1 undef to i32
+; AVX512F-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %H = trunc i32 undef to i1
+; AVX512F-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
+;
+; AVX512BW-LABEL: 'add'
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %A = zext <4 x i1> undef to <4 x i32>
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %B = sext <4 x i1> undef to <4 x i32>
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %C = trunc <4 x i32> undef to <4 x i1>
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %D = zext <8 x i1> undef to <8 x i32>
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %E = sext <8 x i1> undef to <8 x i32>
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %F = trunc <8 x i32> undef to <8 x i1>
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %G = zext i1 undef to i32
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %H = trunc i32 undef to i1
+; AVX512BW-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
+;
+; AVX512DQ-LABEL: 'add'
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %A = zext <4 x i1> undef to <4 x i32>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %B = sext <4 x i1> undef to <4 x i32>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %C = trunc <4 x i32> undef to <4 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %D = zext <8 x i1> undef to <8 x i32>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %E = sext <8 x i1> undef to <8 x i32>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %F = trunc <8 x i32> undef to <8 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %G = zext i1 undef to i32
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %H = trunc i32 undef to i1
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
 ;
   ; -- Same size registeres --
   %A = zext <4 x i1> undef to <4 x i32>
   %B = sext <4 x i1> undef to <4 x i32>
   %C = trunc <4 x i32> undef to <4 x i1>
 
   ; -- Different size registers --
   %D = zext <8 x i1> undef to <8 x i32>

llvm/test/Analysis/CostModel/X86/extend.ll

 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 38 for instruction: %V128i8 = zext <128 x i1> undef to <128 x i8>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
 ;
 ; AVX512DQ-LABEL: 'zext_vXi1'
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %I64 = zext i1 undef to i64
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i64 = zext <2 x i1> undef to <2 x i64>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i64 = zext <4 x i1> undef to <4 x i64>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8i64 = zext <8 x i1> undef to <8 x i64>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 5 for instruction: %V16i64 = zext <16 x i1> undef to <16 x i64>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 10 for instruction: %V32i64 = zext <32 x i1> undef to <32 x i64>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 20 for instruction: %V64i64 = zext <64 x i1> undef to <64 x i64>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 40 for instruction: %V128i64 = zext <128 x i1> undef to <128 x i64>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V16i64 = zext <16 x i1> undef to <16 x i64>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V32i64 = zext <32 x i1> undef to <32 x i64>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %V64i64 = zext <64 x i1> undef to <64 x i64>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %V128i64 = zext <128 x i1> undef to <128 x i64>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %I32 = zext i1 undef to i32
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i32 = zext <2 x i1> undef to <2 x i32>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i32 = zext <4 x i1> undef to <4 x i32>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8i32 = zext <8 x i1> undef to <8 x i32>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V16i32 = zext <16 x i1> undef to <16 x i32>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V32i32 = zext <32 x i1> undef to <32 x i32>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V64i32 = zext <64 x i1> undef to <64 x i32>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %V128i32 = zext <128 x i1> undef to <128 x i32>

 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 30 for instruction: %V128i8 = sext <128 x i1> undef to <128 x i8>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
 ;
 ; AVX512DQ-LABEL: 'sext_vXi1'
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %I64 = sext i1 undef to i64
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2i64 = sext <2 x i1> undef to <2 x i64>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4i64 = sext <4 x i1> undef to <4 x i64>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8i64 = sext <8 x i1> undef to <8 x i64>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %V16i64 = sext <16 x i1> undef to <16 x i64>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %V32i64 = sext <32 x i1> undef to <32 x i64>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: %V64i64 = sext <64 x i1> undef to <64 x i64>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 24 for instruction: %V128i64 = sext <128 x i1> undef to <128 x i64>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V16i64 = sext <16 x i1> undef to <16 x i64>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V32i64 = sext <32 x i1> undef to <32 x i64>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V64i64 = sext <64 x i1> undef to <64 x i64>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %V128i64 = sext <128 x i1> undef to <128 x i64>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %I32 = sext i1 undef to i32
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2i32 = sext <2 x i1> undef to <2 x i32>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4i32 = sext <4 x i1> undef to <4 x i32>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8i32 = sext <8 x i1> undef to <8 x i32>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V16i32 = sext <16 x i1> undef to <16 x i32>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V32i32 = sext <32 x i1> undef to <32 x i32>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V64i32 = sext <64 x i1> undef to <64 x i32>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V128i32 = sext <128 x i1> undef to <128 x i32>

llvm/test/Analysis/CostModel/X86/min-legal-vector-width.ll

 ; SKX256-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i8 = trunc <4 x i8> undef to <4 x i1>
 ; SKX256-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8i8 = trunc <8 x i8> undef to <8 x i1>
 ; SKX256-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V16i8 = trunc <16 x i8> undef to <16 x i1>
 ; SKX256-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V32i8 = trunc <32 x i8> undef to <32 x i1>
 ; SKX256-NEXT:  Cost Model: Found an estimated cost of 5 for instruction: %V64i8 = trunc <64 x i8> undef to <64 x i1>
 ; SKX256-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
 ;
 ; SKX512-LABEL: 'trunc_vXi1'
-; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i64 = trunc <2 x i64> undef to <2 x i1>
-; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i64 = trunc <4 x i64> undef to <4 x i1>
-; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8i64 = trunc <8 x i64> undef to <8 x i1>
+; SKX512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2i64 = trunc <2 x i64> undef to <2 x i1>
+; SKX512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4i64 = trunc <4 x i64> undef to <4 x i1>
+; SKX512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8i64 = trunc <8 x i64> undef to <8 x i1>
 ; SKX512-NEXT:  Cost Model: Found an estimated cost of 11 for instruction: %V16i64 = trunc <16 x i64> undef to <16 x i1>
 ; SKX512-NEXT:  Cost Model: Found an estimated cost of 23 for instruction: %V32i64 = trunc <32 x i64> undef to <32 x i1>
 ; SKX512-NEXT:  Cost Model: Found an estimated cost of 47 for instruction: %V64i64 = trunc <64 x i64> undef to <64 x i1>
 ; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i32 = trunc <2 x i32> undef to <2 x i1>
-; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i32 = trunc <4 x i32> undef to <4 x i1>
-; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8i32 = trunc <8 x i32> undef to <8 x i1>
-; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V16i32 = trunc <16 x i32> undef to <16 x i1>
-; SKX512-NEXT:  Cost Model: Found an estimated cost of 5 for instruction: %V32i32 = trunc <32 x i32> undef to <32 x i1>
-; SKX512-NEXT:  Cost Model: Found an estimated cost of 11 for instruction: %V64i32 = trunc <64 x i32> undef to <64 x i1>
+; SKX512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4i32 = trunc <4 x i32> undef to <4 x i1>
+; SKX512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8i32 = trunc <8 x i32> undef to <8 x i1>
+; SKX512-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V16i32 = trunc <16 x i32> undef to <16 x i1>
+; SKX512-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %V32i32 = trunc <32 x i32> undef to <32 x i1>
+; SKX512-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %V64i32 = trunc <64 x i32> undef to <64 x i1>
 ; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i1>
 ; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i1>
 ; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8i16 = trunc <8 x i16> undef to <8 x i1>
 ; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V16i16 = trunc <16 x i16> undef to <16 x i1>
 ; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V32i16 = trunc <32 x i16> undef to <32 x i1>
 ; SKX512-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V64i16 = trunc <64 x i16> undef to <64 x i1>
 ; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i8 = trunc <2 x i8> undef to <2 x i1>
 ; SKX512-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i8 = trunc <4 x i8> undef to <4 x i1>

llvm/test/Analysis/CostModel/X86/trunc.ll

 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 1280 for instruction: %V640i8 = trunc <640 x i8> undef to <640 x i1>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 1536 for instruction: %V768i8 = trunc <768 x i8> undef to <768 x i1>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 1792 for instruction: %V896i8 = trunc <896 x i8> undef to <896 x i1>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 240 for instruction: %V1024i8 = trunc <1024 x i8> undef to <1024 x i1>
 ; AVX512F-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret i32 undef
 ;
 ; AVX512DQ-LABEL: 'trunc_vXi1'
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %i64 = trunc i64 undef to i1
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i64 = trunc <2 x i64> undef to <2 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V3i64 = trunc <3 x i64> undef to <3 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i64 = trunc <4 x i64> undef to <4 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V5i64 = trunc <5 x i64> undef to <5 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V6i64 = trunc <6 x i64> undef to <6 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V7i64 = trunc <7 x i64> undef to <7 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8i64 = trunc <8 x i64> undef to <8 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 20 for instruction: %V10i64 = trunc <10 x i64> undef to <10 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 24 for instruction: %V12i64 = trunc <12 x i64> undef to <12 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 28 for instruction: %V14i64 = trunc <14 x i64> undef to <14 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V2i64 = trunc <2 x i64> undef to <2 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V3i64 = trunc <3 x i64> undef to <3 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4i64 = trunc <4 x i64> undef to <4 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V5i64 = trunc <5 x i64> undef to <5 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V6i64 = trunc <6 x i64> undef to <6 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V7i64 = trunc <7 x i64> undef to <7 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8i64 = trunc <8 x i64> undef to <8 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V10i64 = trunc <10 x i64> undef to <10 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V12i64 = trunc <12 x i64> undef to <12 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V14i64 = trunc <14 x i64> undef to <14 x i1>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 11 for instruction: %V16i64 = trunc <16 x i64> undef to <16 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 40 for instruction: %V20i64 = trunc <20 x i64> undef to <20 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 48 for instruction: %V24i64 = trunc <24 x i64> undef to <24 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 56 for instruction: %V28i64 = trunc <28 x i64> undef to <28 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 22 for instruction: %V32i64 = trunc <32 x i64> undef to <32 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 80 for instruction: %V40i64 = trunc <40 x i64> undef to <40 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 96 for instruction: %V48i64 = trunc <48 x i64> undef to <48 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 112 for instruction: %V56i64 = trunc <56 x i64> undef to <56 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 44 for instruction: %V64i64 = trunc <64 x i64> undef to <64 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 160 for instruction: %V80i64 = trunc <80 x i64> undef to <80 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 224 for instruction: %V112i64 = trunc <112 x i64> undef to <112 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 88 for instruction: %V128i64 = trunc <128 x i64> undef to <128 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 320 for instruction: %V160i64 = trunc <160 x i64> undef to <160 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 384 for instruction: %V192i64 = trunc <192 x i64> undef to <192 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 448 for instruction: %V224i64 = trunc <224 x i64> undef to <224 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 176 for instruction: %V256i64 = trunc <256 x i64> undef to <256 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 640 for instruction: %V320i64 = trunc <320 x i64> undef to <320 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 768 for instruction: %V384i64 = trunc <384 x i64> undef to <384 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 896 for instruction: %V448i64 = trunc <448 x i64> undef to <448 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 352 for instruction: %V512i64 = trunc <512 x i64> undef to <512 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1280 for instruction: %V640i64 = trunc <640 x i64> undef to <640 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1536 for instruction: %V768i64 = trunc <768 x i64> undef to <768 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1792 for instruction: %V896i64 = trunc <896 x i64> undef to <896 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 704 for instruction: %V1024i64 = trunc <1024 x i64> undef to <1024 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V20i64 = trunc <20 x i64> undef to <20 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V24i64 = trunc <24 x i64> undef to <24 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V28i64 = trunc <28 x i64> undef to <28 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V32i64 = trunc <32 x i64> undef to <32 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V40i64 = trunc <40 x i64> undef to <40 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V48i64 = trunc <48 x i64> undef to <48 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V56i64 = trunc <56 x i64> undef to <56 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V64i64 = trunc <64 x i64> undef to <64 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %V80i64 = trunc <80 x i64> undef to <80 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %V112i64 = trunc <112 x i64> undef to <112 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %V128i64 = trunc <128 x i64> undef to <128 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %V160i64 = trunc <160 x i64> undef to <160 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %V192i64 = trunc <192 x i64> undef to <192 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %V224i64 = trunc <224 x i64> undef to <224 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %V256i64 = trunc <256 x i64> undef to <256 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %V320i64 = trunc <320 x i64> undef to <320 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %V384i64 = trunc <384 x i64> undef to <384 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %V448i64 = trunc <448 x i64> undef to <448 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %V512i64 = trunc <512 x i64> undef to <512 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 128 for instruction: %V640i64 = trunc <640 x i64> undef to <640 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 128 for instruction: %V768i64 = trunc <768 x i64> undef to <768 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 128 for instruction: %V896i64 = trunc <896 x i64> undef to <896 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 128 for instruction: %V1024i64 = trunc <1024 x i64> undef to <1024 x i1>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %i32 = trunc i32 undef to i1
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V2i32 = trunc <2 x i32> undef to <2 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V3i32 = trunc <3 x i32> undef to <3 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V4i32 = trunc <4 x i32> undef to <4 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V5i32 = trunc <5 x i32> undef to <5 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V6i32 = trunc <6 x i32> undef to <6 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V7i32 = trunc <7 x i32> undef to <7 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V8i32 = trunc <8 x i32> undef to <8 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V10i32 = trunc <10 x i32> undef to <10 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V12i32 = trunc <12 x i32> undef to <12 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V14i32 = trunc <14 x i32> undef to <14 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V16i32 = trunc <16 x i32> undef to <16 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V20i32 = trunc <20 x i32> undef to <20 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V24i32 = trunc <24 x i32> undef to <24 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V28i32 = trunc <28 x i32> undef to <28 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V32i32 = trunc <32 x i32> undef to <32 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V40i32 = trunc <40 x i32> undef to <40 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V48i32 = trunc <48 x i32> undef to <48 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V56i32 = trunc <56 x i32> undef to <56 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V64i32 = trunc <64 x i32> undef to <64 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %V80i32 = trunc <80 x i32> undef to <80 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %V112i32 = trunc <112 x i32> undef to <112 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %V128i32 = trunc <128 x i32> undef to <128 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %V160i32 = trunc <160 x i32> undef to <160 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %V192i32 = trunc <192 x i32> undef to <192 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %V224i32 = trunc <224 x i32> undef to <224 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %V256i32 = trunc <256 x i32> undef to <256 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %V320i32 = trunc <320 x i32> undef to <320 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %V384i32 = trunc <384 x i32> undef to <384 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %V448i32 = trunc <448 x i32> undef to <448 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %V512i32 = trunc <512 x i32> undef to <512 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 128 for instruction: %V640i32 = trunc <640 x i32> undef to <640 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 128 for instruction: %V768i32 = trunc <768 x i32> undef to <768 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 128 for instruction: %V896i32 = trunc <896 x i32> undef to <896 x i1>
-; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 128 for instruction: %V1024i32 = trunc <1024 x i32> undef to <1024 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V3i32 = trunc <3 x i32> undef to <3 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V4i32 = trunc <4 x i32> undef to <4 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V5i32 = trunc <5 x i32> undef to <5 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V6i32 = trunc <6 x i32> undef to <6 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V7i32 = trunc <7 x i32> undef to <7 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V8i32 = trunc <8 x i32> undef to <8 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V10i32 = trunc <10 x i32> undef to <10 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V12i32 = trunc <12 x i32> undef to <12 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V14i32 = trunc <14 x i32> undef to <14 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %V16i32 = trunc <16 x i32> undef to <16 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V20i32 = trunc <20 x i32> undef to <20 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V24i32 = trunc <24 x i32> undef to <24 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V28i32 = trunc <28 x i32> undef to <28 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %V32i32 = trunc <32 x i32> undef to <32 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V40i32 = trunc <40 x i32> undef to <40 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V48i32 = trunc <48 x i32> undef to <48 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V56i32 = trunc <56 x i32> undef to <56 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %V64i32 = trunc <64 x i32> undef to <64 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V80i32 = trunc <80 x i32> undef to <80 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V112i32 = trunc <112 x i32> undef to <112 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %V128i32 = trunc <128 x i32> undef to <128 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %V160i32 = trunc <160 x i32> undef to <160 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %V192i32 = trunc <192 x i32> undef to <192 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %V224i32 = trunc <224 x i32> undef to <224 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %V256i32 = trunc <256 x i32> undef to <256 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %V320i32 = trunc <320 x i32> undef to <320 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %V384i32 = trunc <384 x i32> undef to <384 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %V448i32 = trunc <448 x i32> undef to <448 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %V512i32 = trunc <512 x i32> undef to <512 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %V640i32 = trunc <640 x i32> undef to <640 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %V768i32 = trunc <768 x i32> undef to <768 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %V896i32 = trunc <896 x i32> undef to <896 x i1>
+; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %V1024i32 = trunc <1024 x i32> undef to <1024 x i1>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %i16 = trunc i16 undef to i1
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %V2i16 = trunc <2 x i16> undef to <2 x i1>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %V3i16 = trunc <3 x i16> undef to <3 x i1>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %V4i16 = trunc <4 x i16> undef to <4 x i1>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %V5i16 = trunc <5 x i16> undef to <5 x i1>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %V6i16 = trunc <6 x i16> undef to <6 x i1>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %V7i16 = trunc <7 x i16> undef to <7 x i1>
 ; AVX512DQ-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %V8i16 = trunc <8 x i16> undef to <8 x i1>