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author | Bob Wilson <bob.wilson@apple.com> | 2009-10-27 23:49:38 +0000 |
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committer | Bob Wilson <bob.wilson@apple.com> | 2009-10-27 23:49:38 +0000 |
commit | cd4f04d6bcb7aefa24d92582fbadfe17519f4756 (patch) | |
tree | 154762d67c0c4a8d677aeef3bd023b5a1f0f719a /docs/LangRef.html | |
parent | 03236140fa4ef316a605717e090276d6a0d42828 (diff) | |
download | external_llvm-cd4f04d6bcb7aefa24d92582fbadfe17519f4756.zip external_llvm-cd4f04d6bcb7aefa24d92582fbadfe17519f4756.tar.gz external_llvm-cd4f04d6bcb7aefa24d92582fbadfe17519f4756.tar.bz2 |
Record CodeGen optimization level in the BranchFolding pass so that we can
use it to control tail merging when there is a tradeoff between performance
and code size. When there is only 1 instruction in the common tail, we have
been merging. That can be good for code size but is a definite loss for
performance. Now we will avoid tail merging in that case when the
optimization level is "Aggressive", i.e., "-O3". Radar 7338114.
Since the IfConversion pass invokes BranchFolding, it too needs to know
the optimization level. Note that I removed the RegisterPass instantiation
for IfConversion because it required a default constructor. If someone
wants to keep that for some reason, we can add a default constructor with
a hard-wired optimization level.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85346 91177308-0d34-0410-b5e6-96231b3b80d8
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