22ce5eb051
Do not widen load for different variable in GVN.
...
Summary:
Widening load in GVN is too early because it will block other optimizations like PRE, LICM.
https://llvm.org/bugs/show_bug.cgi?id=29110
The SPECCPU2006 benchmark impact of this patch:
Reference: o2_nopatch
(1): o2_patched
Benchmark Base:Reference (1)
-------------------------------------------------------
spec/2006/fp/C++/444.namd 25.2 -0.08%
spec/2006/fp/C++/447.dealII 45.92 +1.05%
spec/2006/fp/C++/450.soplex 41.7 -0.26%
spec/2006/fp/C++/453.povray 35.65 +1.68%
spec/2006/fp/C/433.milc 23.79 +0.42%
spec/2006/fp/C/470.lbm 41.88 -1.12%
spec/2006/fp/C/482.sphinx3 47.94 +1.67%
spec/2006/int/C++/471.omnetpp 22.46 -0.36%
spec/2006/int/C++/473.astar 21.19 +0.24%
spec/2006/int/C++/483.xalancbmk 36.09 -0.11%
spec/2006/int/C/400.perlbench 33.28 +1.35%
spec/2006/int/C/401.bzip2 22.76 -0.04%
spec/2006/int/C/403.gcc 32.36 +0.12%
spec/2006/int/C/429.mcf 41.04 -0.41%
spec/2006/int/C/445.gobmk 26.94 +0.04%
spec/2006/int/C/456.hmmer 24.5 -0.20%
spec/2006/int/C/458.sjeng 28 -0.46%
spec/2006/int/C/462.libquantum 55.25 +0.27%
spec/2006/int/C/464.h264ref 45.87 +0.72%
geometric mean +0.23%
For most benchmarks, it's a wash, but we do see stable improvements on some benchmarks, e.g. 447,453,482,400.
Reviewers: davidxl, hfinkel, dberlin, sanjoy, reames
Subscribers: gberry, junbuml
Differential Revision: https://reviews.llvm.org/D24096
llvm-svn: 281074
2016-09-09 18:42:35 +00:00
b69babd01e
Fix bug 25440: GVN assertion after coercing loads
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Optimizations like LoadPRE in GVN will insert new instructions.
If the insertion point is in a already processed BB, they should
get a value number explicitly. If the insertion point is after
current instruction, then just leave it. However, current GVN framework
has no support for it.
In this patch, we just bail out if a VN can't be found.
Dfferential Revision: http://reviews.llvm.org/D14670
A test/Transforms/GVN/pr25440.ll
M lib/Transforms/Scalar/GVN.cpp
llvm-svn: 253536
2015-11-19 02:45:18 +00:00
eed0145dd2
Fix bug 25440: GVN assertion after coercing loads
...
Summary:
when coercing loads, it inserts some instructions, which have no GV assigned.
https://llvm.org/bugs/show_bug.cgi?id=25440
Reviewers: hfinkel, dberlin
Subscribers: dberlin, llvm-commits
Differential Revision: http://reviews.llvm.org/D14479
llvm-svn: 252919
2015-11-12 18:19:59 +00:00
Dehao Chen