[PATCH] D76611: [SCCP] Use ranges for predicate info conditions.

Mon Mar 23 07:36:31 PDT 2020

fhahn created this revision.
fhahn added reviewers: efriedma, davide.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.

This patch updates the code that deals with conditions from predicate
info to make use of constant ranges.

For ssa_copy instructions inserted by PredicateInfo, we have 2 ranges:

1. The range of the original value.
2. The range imposed by the linked condition.

1. is known, 2. can be determined using makeAllowedICmpRegion. The

intersection of those ranges is the range for the copy.

With this patch, we get a nice increase in the number of instructions
eliminated by both SCCP and IPSCCP for some benchmarks:

For MultiSource, SPEC2000 & SPEC2006:

Tests: 237
Same hash: 170 (filtered out)
Remaining: 67
Metric: sccp.NumInstRemoved
Program                                        base    patch   diff
 test-suite...Source/Benchmarks/sim/sim.test    10.00   71.00  610.0%
 test-suite...CFP2000/177.mesa/177.mesa.test   361.00  1626.00 350.4%
 test-suite...encode/alacconvert-encode.test   141.00  602.00  327.0%
 test-suite...decode/alacconvert-decode.test   141.00  602.00  327.0%
 test-suite...CI_Purple/SMG2000/smg2000.test   1639.00 4093.00 149.7%
 test-suite...peg2/mpeg2dec/mpeg2decode.test    75.00  163.00  117.3%
 test-suite...T2006/401.bzip2/401.bzip2.test   358.00  513.00  43.3%
 test-suite...rks/FreeBench/pifft/pifft.test    11.00   15.00  36.4%
 test-suite...langs-C/unix-tbl/unix-tbl.test     4.00    5.00  25.0%
 test-suite...lications/sqlite3/sqlite3.test   541.00  667.00  23.3%
 test-suite.../CINT2000/254.gap/254.gap.test   243.00  299.00  23.0%
 test-suite...ks/Prolangs-C/agrep/agrep.test    25.00   29.00  16.0%
 test-suite...marks/7zip/7zip-benchmark.test   1135.00 1304.00 14.9%
 test-suite...lications/ClamAV/clamscan.test   1105.00 1268.00 14.8%
 test-suite...urce/Applications/lua/lua.test   398.00  436.00   9.5%

Metric: sccp.IPNumInstRemoved
Program                                        base   patch   diff
 test-suite...C/CFP2000/179.art/179.art.test     1.00   3.00  200.0%
 test-suite...006/447.dealII/447.dealII.test   429.00 1056.00 146.2%
 test-suite...nch/fourinarow/fourinarow.test     3.00   7.00  133.3%
 test-suite...CI_Purple/SMG2000/smg2000.test   818.00 1748.00 113.7%
 test-suite...ks/McCat/04-bisect/bisect.test     3.00   5.00  66.7%
 test-suite...CFP2000/177.mesa/177.mesa.test   165.00 255.00  54.5%
 test-suite...ediabench/gsm/toast/toast.test    18.00  27.00  50.0%
 test-suite...telecomm-gsm/telecomm-gsm.test    18.00  27.00  50.0%
 test-suite...ks/Prolangs-C/agrep/agrep.test    24.00  35.00  45.8%
 test-suite...TimberWolfMC/timberwolfmc.test    43.00  62.00  44.2%
 test-suite...encode/alacconvert-encode.test    46.00  66.00  43.5%
 test-suite...decode/alacconvert-decode.test    46.00  66.00  43.5%
 test-suite...langs-C/unix-tbl/unix-tbl.test    12.00  17.00  41.7%
 test-suite...peg2/mpeg2dec/mpeg2decode.test    31.00  41.00  32.3%
 test-suite.../CINT2000/254.gap/254.gap.test   117.00 154.00  31.6%

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D76611

Files:
  llvm/lib/Transforms/Scalar/SCCP.cpp
  llvm/test/Transforms/SCCP/conditions-ranges.ll
  llvm/test/Transforms/SCCP/ip-constant-ranges.ll

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