tree 56d9e460b719d9e944ee80f22b548c525c7dd914
parent 3d4f91d8d07a589fd89ce28669c1c8f67420c8aa
author Amara Emerson <aemerson@apple.com> 1555304660 +0000
committer Amara Emerson <aemerson@apple.com> 1555304660 +0000

[GlobalISel] Enable CSE in the IRTranslator & legalizer for -O0 with constants only.

Other opcodes shouldn't be CSE'd until we can be sure debug info quality won't
be degraded.

This change also improves the IRTranslator so that in most places, but not all,
it creates constants using the MIRBuilder directly instead of first creating a
new destination vreg and then creating a constant. By doing this, the
buildConstant() method can just return the vreg of an existing G_CONSTANT
instead of having to create a COPY from it.

I measured a 0.2% improvement in compile time and a 0.9% improvement in code
size at -O0 ARM64.

Compile time:
Program                                        base   cse    diff
test-suite...ark/tramp3d-v4/tramp3d-v4.test     9.04   9.12  0.8%
test-suite...Mark/mafft/pairlocalalign.test     2.68   2.66 -0.7%
test-suite...-typeset/consumer-typeset.test     5.53   5.51 -0.4%
test-suite :: CTMark/lencod/lencod.test         5.30   5.28 -0.3%
test-suite :: CTMark/Bullet/bullet.test        25.82  25.76 -0.2%
test-suite...:: CTMark/ClamAV/clamscan.test     6.92   6.90 -0.2%
test-suite...TMark/7zip/7zip-benchmark.test    34.24  34.17 -0.2%
test-suite :: CTMark/SPASS/SPASS.test           6.25   6.24 -0.1%
test-suite...:: CTMark/sqlite3/sqlite3.test     1.66   1.66 -0.1%
test-suite :: CTMark/kimwitu++/kc.test         13.61  13.60 -0.0%
Geomean difference                                          -0.2%

Code size:
Program                                        base     cse      diff
test-suite...-typeset/consumer-typeset.test    1315632  1266480 -3.7%
test-suite...:: CTMark/ClamAV/clamscan.test    1313892  1297508 -1.2%
test-suite :: CTMark/lencod/lencod.test        1439504  1423112 -1.1%
test-suite...TMark/7zip/7zip-benchmark.test    2936980  2904172 -1.1%
test-suite :: CTMark/Bullet/bullet.test        3478276  3445460 -0.9%
test-suite...ark/tramp3d-v4/tramp3d-v4.test    8082868  8033492 -0.6%
test-suite :: CTMark/kimwitu++/kc.test         3870380  3853972 -0.4%
test-suite :: CTMark/SPASS/SPASS.test          1434904  1434896 -0.0%
test-suite...Mark/mafft/pairlocalalign.test    764528   764528   0.0%
test-suite...:: CTMark/sqlite3/sqlite3.test    782092   782092   0.0%
Geomean difference                                              -0.9%

Differential Revision: https://reviews.llvm.org/D60580

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358369 91177308-0d34-0410-b5e6-96231b3b80d8