mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-10-02 02:55:35 +00:00
LLVM backend for 6502
e79d92c592
Add support for matching 'ordered' and 'unordered' floating point min/max constructs. In LLVM we can express min/max functions as a combination of compare and select. We have support for matching such constructs for integers but not for floating point. In floating point math there is no total order because of the presence of 'NaN'. Therefore, we have to be careful to preserve the original fcmp semantics when interpreting floating point compare select combinations as a minimum or maximum function. The resulting 'ordered/unordered' floating point maximum function has to select the same value as the select/fcmp combination it is based on. ordered_max(x,y) = max(x,y) iff x and y are not NaN, y otherwise unordered_max(x,y) = max(x,y) iff x and y are not NaN, x otherwise ordered_min(x,y) = min(x,y) iff x and y are not NaN, y otherwise unordered_min(x,y) = min(x,y) iff x and y are not NaN, x otherwise This matches the behavior of the underlying select(fcmp(olt/ult/.., L, R), L, R) construct. Any code using this predicate has to preserve this semantics. A follow-up patch will use this to implement floating point min/max reductions in the vectorizer. radar://13723044 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181143 91177308-0d34-0410-b5e6-96231b3b80d8 |
||
|---|---|---|
| autoconf | ||
| bindings | ||
| cmake | ||
| docs | ||
| examples | ||
| include | ||
| lib | ||
| projects | ||
| runtime | ||
| test | ||
| tools | ||
| unittests | ||
| utils | ||
| .arcconfig | ||
| .gitignore | ||
| CMakeLists.txt | ||
| CODE_OWNERS.TXT | ||
| configure | ||
| CREDITS.TXT | ||
| LICENSE.TXT | ||
| llvm.spec.in | ||
| LLVMBuild.txt | ||
| Makefile | ||
| Makefile.common | ||
| Makefile.config.in | ||
| Makefile.rules | ||
| README.txt | ||
Low Level Virtual Machine (LLVM) ================================ This directory and its subdirectories contain source code for the Low Level Virtual Machine, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments. LLVM is open source software. You may freely distribute it under the terms of the license agreement found in LICENSE.txt. Please see the documentation provided in docs/ for further assistance with LLVM, and in particular docs/GettingStarted.rst for getting started with LLVM and docs/README.txt for an overview of LLVM's documentation setup. If you're writing a package for LLVM, see docs/Packaging.rst for our suggestions.