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Differential D95051

[AMDGPU] pin lit test divergent-unswitch.ll to the old pass manager
ClosedPublic

Authored by sameerds on Jan 20 2021, 8:09 AM.

Details

Reviewers
foad
arsenm
rampitec
Commits
rGc540ce9900ff: [AMDGPU] pin lit test divergent-unswitch.ll to the old pass manager
Summary

The loop-unswitch transform should not be performed on a loop whose
condition is divergent. For this to happen correctly, divergence
analysis must be available. The existing divergence analysis has not
been ported to the new pass manager yet. As a result, loop unswitching
on the new pass manager is currently unsafe on targets that care about
divergence.

This test is temporarily disabled to unblock work on the new pass
manager. The issue is now tracked in bug 48819.

Change-Id: I05da823b1377c9a1d61ce8bc8ea11eb0bb09f0f1

Diff Detail

Event Timeline

sameerds created this revision.Jan 20 2021, 8:09 AM
Herald added subscribers: kerbowa, t-tye, tpr and 5 others. · View Herald TranscriptJan 20 2021, 8:09 AM
sameerds requested review of this revision.Jan 20 2021, 8:09 AM
Herald added a project: Restricted Project. · View Herald TranscriptJan 20 2021, 8:09 AM
Herald added subscribers: llvm-commits, wdng. · View Herald Transcript
sameerds added reviewers: foad, arsenm, rampitec.Jan 20 2021, 8:10 AM
sameerds added a subscriber: aeubanks.
foad accepted this revision.Jan 20 2021, 8:16 AM

LGTM.

This revision is now accepted and ready to land.Jan 20 2021, 8:16 AM
This revision was landed with ongoing or failed builds.Jan 20 2021, 8:33 AM
Closed by commit rGc540ce9900ff: [AMDGPU] pin lit test divergent-unswitch.ll to the old pass manager (authored by sameerds). · Explain Why
This revision was automatically updated to reflect the committed changes.
sameerds added a commit: rGc540ce9900ff: [AMDGPU] pin lit test divergent-unswitch.ll to the old pass manager.
Harbormaster completed remote builds in B85894: Diff 317885.Jan 20 2021, 9:40 AM

Revision Contents

PathSize
llvm/
test/
Transforms/
LoopUnswitch/
AMDGPU/
5 lines

Diff 317890

llvm/test/Transforms/LoopUnswitch/AMDGPU/divergent-unswitch.ll

; RUN: opt -mtriple=amdgcn-- -O3 -S %s | FileCheck %s ; RUN: opt -mtriple=amdgcn-- -O3 -S -enable-new-pm=0 %s | FileCheck %s
; This fails with the new pass manager:
; https://bugs.llvm.org/show_bug.cgi?id=48819
; Check that loop unswitch happened and condition hoisted out of the loop. ; Check that loop unswitch happened and condition hoisted out of the loop.
; Condition is uniform so all targets should perform unswitching. ; Condition is uniform so all targets should perform unswitching.
; CHECK-LABEL: {{^}}define amdgpu_kernel void @uniform_unswitch ; CHECK-LABEL: {{^}}define amdgpu_kernel void @uniform_unswitch
; CHECK: entry: ; CHECK: entry:
; CHECK-NEXT: [[LOOP_COND:%[a-z0-9]+]] = icmp ; CHECK-NEXT: [[LOOP_COND:%[a-z0-9]+]] = icmp
; CHECK-NEXT: [[IF_COND:%[a-z0-9]+]] = icmp eq i32 %x, 123456 ; CHECK-NEXT: [[IF_COND:%[a-z0-9]+]] = icmp eq i32 %x, 123456
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