[PATCH] D83667: [ARM] Fix IT block generation after Thumb2SizeReduce with -Oz

Mon Jul 13 03:36:11 PDT 2020

NickGuy created this revision.
NickGuy added reviewers: samparker, SjoerdMeijer, dmgreen, olista01.
NickGuy added a project: LLVM.
Herald added subscribers: danielkiss, hiraditya, kristof.beyls.

Fixes a regression caused by D82439 <https://reviews.llvm.org/D82439>, in which IT blocks were no longer being
generated when -Oz is present. This was due to the CPSR register being marked as
dead, while this case was not accounted for.

Tests: 310
Metric: size..text

| Program                                     | Pre-patch | Post-patch | diff  |
| ------------------------------------------- | --------- | ---------- | ----- |
| test-suite.../Prolangs-C++/ocean/ocean.test | 2168      | 2160       | -0.4% |
| test-suite...s/Misc/richards_benchmark.test | 1432      | 1428       | -0.3% |
| test-suite...out-C++/Shootout-C++-hash.test | 1696      | 1692       | -0.2% |
| test-suite...ut-C++/Shootout-C++-hash2.test | 1924      | 1920       | -0.2% |
| test-suite.../Applications/spiff/spiff.test | 12200     | 12176      | -0.2% |
| test-suite.../Benchmarks/Ptrdist/ks/ks.test | 2768      | 2764       | -0.1% |
| test-suite...Source/Benchmarks/sim/sim.test | 8712      | 8704       | -0.1% |
| test-suite...s/MallocBench/cfrac/cfrac.test | 12360     | 12352      | -0.1% |
| test-suite...lFlow-dbl/ControlFlow-dbl.test | 12896     | 12888      | -0.1% |
| test-suite...chmarks/MallocBench/gs/gs.test | 78160     | 78112      | -0.1% |
| test-suite...lications/sqlite3/sqlite3.test | 168436    | 168340     | -0.1% |
| test-suite...telecomm-gsm/telecomm-gsm.test | 15012     | 15004      | -0.1% |
| test-suite...ediabench/gsm/toast/toast.test | 15012     | 15004      | -0.1% |
| test-suite...urce/Applications/hbd/hbd.test | 18504     | 18496      | -0.0% |
| test-suite...encode/alacconvert-encode.test | 19924     | 19916      | -0.0% |
| test-suite...decode/alacconvert-decode.test | 19924     | 19916      | -0.0% |
| test-suite.../Benchmarks/Ptrdist/bc/bc.test | 20752     | 20744      | -0.0% |
| test-suite...BLambdaLoops/lcalsBLambda.test | 85764     | 85732      | -0.0% |
| test-suite...pplications/oggenc/oggenc.test | 90176     | 90144      | -0.0% |
| test-suite...SubsetCRawLoops/lcalsCRaw.test | 90532     | 90500      | -0.0% |
| test-suite...CLambdaLoops/lcalsCLambda.test | 90628     | 90596      | -0.0% |
| test-suite...ks/Prolangs-C/agrep/agrep.test | 23884     | 23876      | -0.0% |
| test-suite...lFlow-flt/ControlFlow-flt.test | 13384     | 13380      | -0.0% |
| test-suite...lications/ClamAV/clamscan.test | 245996    | 245924     | -0.0% |
| test-suite...terchange/LoopInterchange.test | 59128     | 59112      | -0.0% |
| test-suite...eProcessing/Dilate/Dilate.test | 60376     | 60360      | -0.0% |
| test-suite...Filtering/BilateralFilter.test | 60632     | 60616      | -0.0% |
| test-suite...sion/AnisotropicDiffusion.test | 60680     | 60664      | -0.0% |
| test-suite...ImageProcessing/Blur/blur.test | 61016     | 61000      | -0.0% |
| test-suite...eProcessing/Dither/Dither.test | 61304     | 61288      | -0.0% |
| test-suite...urce/Applications/lua/lua.test | 61520     | 61504      | -0.0% |
| test-suite...yApps-C++/PENNANT/PENNANT.test | 32276     | 32268      | -0.0% |
| test-suite...ProxyApps-C++/CLAMR/CLAMR.test | 217388    | 217340     | -0.0% |
| test-suite...-typeset/consumer-typeset.test | 279140    | 279084     | -0.0% |
| test-suite.../Applications/SPASS/SPASS.test | 201528    | 201488     | -0.0% |
| test-suite...ications/JM/ldecod/ldecod.test | 128356    | 128332     | -0.0% |
| test-suite...SubsetBRawLoops/lcalsBRaw.test | 85748     | 85732      | -0.0% |
| test-suite...plications/d/make_dparser.test | 43956     | 43964      | 0.0%  |
| test-suite...SubsetARawLoops/lcalsARaw.test | 88532     | 88516      | -0.0% |
| test-suite...ALambdaLoops/lcalsALambda.test | 89396     | 89380      | -0.0% |
| test-suite...arks/mafft/pairlocalalign.test | 168656    | 168632     | -0.0% |
| test-suite...nsumer-jpeg/consumer-jpeg.test | 60000     | 59992      | -0.0% |
| test-suite...abench/jpeg/jpeg-6a/cjpeg.test | 61920     | 61912      | -0.0% |
| test-suite...ce/Benchmarks/PAQ8p/paq8p.test | 40636     | 40632      | -0.0% |
| test-suite...CI_Purple/SMG2000/smg2000.test | 89536     | 89544      | 0.0%  |
| test-suite...rks/tramp3d-v4/tramp3d-v4.test | 198420    | 198404     | -0.0% |
| test-suite...ications/JM/lencod/lencod.test | 317976    | 317952     | -0.0% |
| test-suite...Applications/kimwitu++/kc.test | 241500    | 241492     | -0.0% |
| test-suite.../Benchmarks/Bullet/bullet.test | 296420    | 296412     | -0.0% |
| test-suite...marks/7zip/7zip-benchmark.test | 323580    | 323584     | 0.0%  |
| test-suite...peg2/mpeg2dec/mpeg2decode.test | 22968     | 22976      | 0.0%  |
| test-suite...cations/hexxagon/hexxagon.test | 7224      | 7228       | 0.1%  |
| test-suite...s/Ptrdist/anagram/anagram.test | 1940      | 1944       | 0.2%  |
| test-suite...Adobe-C++/stepanov_vector.test | 7888      | 7904       | 0.2%  |
| test-suite...-C++/stepanov_abstraction.test | 6340      | 6356       | 0.3%  |
| Geomean difference                          |           |            | -0.0% |
|



|       | Pre-Patch     | Post-Patch    | diff       |
| ----- | ------------- | ------------- | ---------- |
| count | 310.000000    | 310.000000    | 310.000000 |
| mean  | 19626.800000  | 19624.077419  | -0.000062  |
| std   | 48727.318461  | 48720.664877  | 0.000428   |
| min   | 292.000000    | 292.000000    | -0.003690  |
| 25%   | 1090.000000   | 1090.000000   | 0.000000   |
| 50%   | 2772.000000   | 2770.000000   | 0.000000   |
| 75%   | 10185.000000  | 10185.000000  | 0.000000   |
| max   | 323580.000000 | 323584.000000 | 0.002524   |


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D83667

Files:
  llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
  llvm/test/CodeGen/Thumb2/constant-hoisting.ll


Index: llvm/test/CodeGen/Thumb2/constant-hoisting.ll
===================================================================

--- llvm/test/CodeGen/Thumb2/constant-hoisting.ll
+++ llvm/test/CodeGen/Thumb2/constant-hoisting.ll
@@ -37,26 +37,25 @@
 ; CHECK-V7M:         mov r2, r0
 ; CHECK-V7M-NEXT:    ldr r0, .LCPI0_0
 ; CHECK-V7M-NEXT:    cmp r2, #50
-; CHECK-V7M-NEXT:    beq .LBB0_5
+; CHECK-V7M-NEXT:    beq .LBB0_3
 ; CHECK-V7M-NEXT:    cmp r2, #1
-; CHECK-V7M-NEXT:    beq .LBB0_7
+; CHECK-V7M-NEXT:    ittt eq
+; CHECK-V7M-NEXT:    addeq r0, r1
+; CHECK-V7M-NEXT:    addseq r0, #1
+; CHECK-V7M-NEXT:    bxeq lr
 ; CHECK-V7M-NEXT:    cmp r2, #30
-; CHECK-V7M-NEXT:    beq .LBB0_8
-; CHECK-V7M-NEXT:    cbnz r2, .LBB0_6
+; CHECK-V7M-NEXT:    ittt eq
+; CHECK-V7M-NEXT:    addeq r0, r1
+; CHECK-V7M-NEXT:    addseq r0, #2
+; CHECK-V7M-NEXT:    bxeq lr
+; CHECK-V7M-NEXT:    cbnz r2, .LBB0_4
+; CHECK-V7M-NEXT:  .LBB0_2:
 ; CHECK-V7M-NEXT:    add r0, r1
 ; CHECK-V7M-NEXT:    bx lr
-; CHECK-V7M-NEXT:  .LBB0_5:
+; CHECK-V7M-NEXT:  .LBB0_3:
 ; CHECK-V7M-NEXT:    add r0, r1
 ; CHECK-V7M-NEXT:    adds r0, #4
-; CHECK-V7M-NEXT:  .LBB0_6:
-; CHECK-V7M-NEXT:    bx lr
-; CHECK-V7M-NEXT:  .LBB0_7:
-; CHECK-V7M-NEXT:    add r0, r1
-; CHECK-V7M-NEXT:    adds r0, #1
-; CHECK-V7M-NEXT:    bx lr
-; CHECK-V7M-NEXT:  .LBB0_8:
-; CHECK-V7M-NEXT:    add r0, r1
-; CHECK-V7M-NEXT:    adds r0, #2
+; CHECK-V7M-NEXT:  .LBB0_4:
 ; CHECK-V7M-NEXT:    bx lr
 ; CHECK-V7M-NEXT:    .p2align 2
 ; CHECK-V7M-NEXT:  .LCPI0_0:
Index: llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
===================================================================
--- llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
+++ llvm/lib/Target/ARM/ARMBaseInstrInfo.cpp
@@ -574,7 +574,7 @@
   for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
     const MachineOperand &MO = MI.getOperand(i);
     if ((MO.isRegMask() && MO.clobbersPhysReg(ARM::CPSR)) ||
-        (MO.isReg() && MO.isDef() && MO.getReg() == ARM::CPSR)) {
+        (MO.isReg() && MO.isDef() && MO.getReg() == ARM::CPSR && !MO.isDead())) {
       Pred.push_back(MO);
       Found = true;
     }


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