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[X86] Remove TuningPOPCNTFalseDeps from AlderLake #154004

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Merged
merged 1 commit into from
Aug 18, 2025
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[X86] Remove TuningPOPCNTFalseDeps from AlderLake #154004

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4 changes: 3 additions & 1 deletion llvm/lib/Target/X86/X86.td
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Original file line number Diff line number Diff line change
Expand Up @@ -1291,7 +1291,9 @@ def ProcessorFeatures {
list<SubtargetFeature> ADLAdditionalTuning = [TuningPERMFalseDeps,
TuningPreferMovmskOverVTest,
TuningFastImmVectorShift];
list<SubtargetFeature> ADLTuning = !listconcat(SKLTuning, ADLAdditionalTuning);
list<SubtargetFeature> ADLRemoveTuning = [TuningPOPCNTFalseDeps];
list<SubtargetFeature> ADLTuning =
!listremove(!listconcat(SKLTuning, ADLAdditionalTuning), ADLRemoveTuning);
list<SubtargetFeature> ADLFeatures =
!listconcat(TRMFeatures, ADLAdditionalFeatures);

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9 changes: 9 additions & 0 deletions llvm/test/CodeGen/X86/bitcnt-false-dep.ll
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=haswell | FileCheck %s --check-prefix=HSW
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=skylake | FileCheck %s --check-prefix=SKL
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=skx | FileCheck %s --check-prefix=SKL
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=alderlake | FileCheck %s --check-prefix=ADL
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@RKSimon RKSimon Aug 18, 2025

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Can this file be generated with the update script and we share more prefixes?

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@boomanaiden154 boomanaiden154 Aug 18, 2025

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Not sure if there are specific features that you have in mind for update_llc_test_checks.py that I'm unfamiliar with, but I don't think it makes a ton of sense here.

We end up having to assert the codegen for the entire function rather than just the bit counting instructions/xors that we're interested in. The new ADL lines will also still be unique as well.

Happy to follow up postcommit if there is a simpler way to do this.

; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=silvermont -mattr=+lzcnt,+bmi | FileCheck %s --check-prefix=SKL
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -mcpu=goldmont -mattr=+lzcnt,+bmi | FileCheck %s --check-prefix=SKL

Expand Down Expand Up @@ -37,6 +38,10 @@ ret:
;SKL-LABEL:@loopdep_popcnt32
;SKL: xorl [[GPR0:%e[a-d]x]], [[GPR0]]
;SKL-NEXT: popcntl {{.*}}, [[GPR0]]

;ADL-LABEL:@loopdep_popcnt32
;ADL-NOT: xor
;ADL: popcntl
}

define i64 @loopdep_popcnt64(ptr nocapture %x, ptr nocapture %y) nounwind {
Expand All @@ -63,6 +68,10 @@ ret:
;SKL-LABEL:@loopdep_popcnt64
;SKL: xorl %e[[GPR0:[a-d]x]], %e[[GPR0]]
;SKL-NEXT: popcntq {{.*}}, %r[[GPR0]]

;ADL-LABEL:@loopdep_popcnt64
;ADL-NOT: xor
;ADL: popcntq
}

define i32 @loopdep_tzct32(ptr nocapture %x, ptr nocapture %y) nounwind {
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