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Differential D61283

[SLP] Lit test that cannot get vectorized due to lack of look-ahead operand reordering heuristic.
ClosedPublic

Authored by vporpo on Apr 29 2019, 3:40 PM.

Details

Reviewers
ABataev
RKSimon
Commits
rG83098d28a1e6: [SLP] Lit test that cannot get vectorized due to lack of look-ahead operand…
rL359553: [SLP] Lit test that cannot get vectorized due to lack of look-ahead operand…
Summary

The code in this test is not vectorized by SLP because its operand reordering cannot look beyond the immediate predecessors.
This will get fixed in a follow-up patch that introduces the look-ahead operand reordering heuristic.

Diff Detail

Repository
rL LLVM

Event Timeline

vporpo created this revision.Apr 29 2019, 3:40 PM
Herald added a subscriber: llvm-commits. · View Herald TranscriptApr 29 2019, 3:40 PM
vporpo added a comment.Apr 29 2019, 3:52 PM

@ABataev requested this to be checked in before the look-ahead patch. Please commit this if it looks good, I don't have commit access.

RKSimon accepted this revision.Apr 30 2019, 3:53 AM
This revision is now accepted and ready to land.Apr 30 2019, 3:53 AM
Closed by commit rL359553: [SLP] Lit test that cannot get vectorized due to lack of look-ahead operand… (authored by RKSimon). · Explain WhyApr 30 2019, 4:03 AM
This revision was automatically updated to reflect the committed changes.

Revision Contents

PathSize
llvm/
trunk/
test/
Transforms/
SLPVectorizer/
X86/
74 lines

Diff 197293

llvm/trunk/test/Transforms/SLPVectorizer/X86/lookahead.ll

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -slp-vectorizer -S < %s -mtriple=x86_64-unknown-linux -mcpu=corei7-avx | FileCheck %s
;
; This checks the look-ahead operand reordering heuristic
;
; A[0] B[0] C[0] D[0] C[1] D[1] A[1] B[1]
; \ / \ / \ / \ /
; - - - -
; \ / \ /
; + +
; | |
; S[0] S[1]
;
define void @test(double* %array) {
; CHECK-LABEL: @test(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[IDX0:%.*]] = getelementptr inbounds double, double* [[ARRAY:%.*]], i64 0
; CHECK-NEXT: [[IDX1:%.*]] = getelementptr inbounds double, double* [[ARRAY]], i64 1
; CHECK-NEXT: [[IDX2:%.*]] = getelementptr inbounds double, double* [[ARRAY]], i64 2
; CHECK-NEXT: [[IDX3:%.*]] = getelementptr inbounds double, double* [[ARRAY]], i64 3
; CHECK-NEXT: [[IDX4:%.*]] = getelementptr inbounds double, double* [[ARRAY]], i64 4
; CHECK-NEXT: [[IDX5:%.*]] = getelementptr inbounds double, double* [[ARRAY]], i64 5
; CHECK-NEXT: [[IDX6:%.*]] = getelementptr inbounds double, double* [[ARRAY]], i64 6
; CHECK-NEXT: [[IDX7:%.*]] = getelementptr inbounds double, double* [[ARRAY]], i64 7
; CHECK-NEXT: [[A_0:%.*]] = load double, double* [[IDX0]], align 8
; CHECK-NEXT: [[A_1:%.*]] = load double, double* [[IDX1]], align 8
; CHECK-NEXT: [[B_0:%.*]] = load double, double* [[IDX2]], align 8
; CHECK-NEXT: [[B_1:%.*]] = load double, double* [[IDX3]], align 8
; CHECK-NEXT: [[C_0:%.*]] = load double, double* [[IDX4]], align 8
; CHECK-NEXT: [[C_1:%.*]] = load double, double* [[IDX5]], align 8
; CHECK-NEXT: [[D_0:%.*]] = load double, double* [[IDX6]], align 8
; CHECK-NEXT: [[D_1:%.*]] = load double, double* [[IDX7]], align 8
; CHECK-NEXT: [[SUBAB_0:%.*]] = fsub fast double [[A_0]], [[B_0]]
; CHECK-NEXT: [[SUBCD_0:%.*]] = fsub fast double [[C_0]], [[D_0]]
; CHECK-NEXT: [[SUBAB_1:%.*]] = fsub fast double [[A_1]], [[B_1]]
; CHECK-NEXT: [[SUBCD_1:%.*]] = fsub fast double [[C_1]], [[D_1]]
; CHECK-NEXT: [[ADDABCD_0:%.*]] = fadd fast double [[SUBAB_0]], [[SUBCD_0]]
; CHECK-NEXT: [[ADDCDAB_1:%.*]] = fadd fast double [[SUBCD_1]], [[SUBAB_1]]
; CHECK-NEXT: store double [[ADDABCD_0]], double* [[IDX0]], align 8
; CHECK-NEXT: store double [[ADDCDAB_1]], double* [[IDX1]], align 8
; CHECK-NEXT: ret void
;
entry:
%idx0 = getelementptr inbounds double, double* %array, i64 0
%idx1 = getelementptr inbounds double, double* %array, i64 1
%idx2 = getelementptr inbounds double, double* %array, i64 2
%idx3 = getelementptr inbounds double, double* %array, i64 3
%idx4 = getelementptr inbounds double, double* %array, i64 4
%idx5 = getelementptr inbounds double, double* %array, i64 5
%idx6 = getelementptr inbounds double, double* %array, i64 6
%idx7 = getelementptr inbounds double, double* %array, i64 7
%A_0 = load double, double *%idx0, align 8
%A_1 = load double, double *%idx1, align 8
%B_0 = load double, double *%idx2, align 8
%B_1 = load double, double *%idx3, align 8
%C_0 = load double, double *%idx4, align 8
%C_1 = load double, double *%idx5, align 8
%D_0 = load double, double *%idx6, align 8
%D_1 = load double, double *%idx7, align 8
%subAB_0 = fsub fast double %A_0, %B_0
%subCD_0 = fsub fast double %C_0, %D_0
%subAB_1 = fsub fast double %A_1, %B_1
%subCD_1 = fsub fast double %C_1, %D_1
%addABCD_0 = fadd fast double %subAB_0, %subCD_0
%addCDAB_1 = fadd fast double %subCD_1, %subAB_1
store double %addABCD_0, double *%idx0, align 8
store double %addCDAB_1, double *%idx1, align 8
ret void
}