6502
/
llvm-6502
mirror of https://github.com/c64scene-ar/llvm-6502.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

[PerformanceTips] Italics are *word*, not _word_ 

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235827 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Philip Reames 2015-04-26 22:25:29 +00:00
parent fb3da5cce1
commit 94bd029c3d
1 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
docs/Frontend/PerformanceTips.rst
View File

@ -142,18 +142,18 @@ Other things to consider
this guidance is that a unified return block with high in-degree is fine.
#. When checking a value against a constant, emit the check using a consistent
comparison type. The GVN pass _will_ optimize redundant equalities even if
comparison type. The GVN pass *will* optimize redundant equalities even if
the type of comparison is inverted, but GVN only runs late in the pipeline.
As a result, you may miss the opportunity to run other important
optimizations. Improvements to EarlyCSE to remove this issue are tracked in
Bug 23333.
#. Avoid using arithmetic intrinsics unless you are _required_ by your source
#. Avoid using arithmetic intrinsics unless you are *required* by your source
language specification to emit a particular code sequence. The optimizer
is quite good at reasoning about general control flow and arithmetic, it is
not anywhere near as strong at reasoning about the various intrinsics. If
profitable for code generation purposes, the optimizer will likely form the
intrinsics itself late in the optimization pipeline. It is _very_ rarely
intrinsics itself late in the optimization pipeline. It is *very* rarely
profitable to emit these directly in the language frontend. This item
explicitly includes the use of the :ref:`overflow intrinsics <int_overflow>`.