forked from OSchip/llvm-project
c00e03b8f5
Summary: The presence of this attribute indicates that VGPR outputs should be computed in whole quad mode. This will be used by Mesa for prolog pixel shaders, so that derivatives can be taken of shader inputs computed by the prolog, fixing a bug. The generated code could certainly be improved: if a prolog pixel shader is used (which isn't common in modern OpenGL - they're used for gl_Color, polygon stipples, and forcing per-sample interpolation), Mesa will use this attribute unconditionally, because it has to be conservative. So WQM may be used in the prolog when it isn't really needed, and furthermore a silly back-and-forth switch is likely to happen at the boundary between prolog and main shader parts. Fixing this is a bit involved: we'd first have to add a mechanism by which LLVM writes the WQM-related input requirements to the main shader part binary, and then Mesa specializes the prolog part accordingly. At that point, we may as well just compile a monolithic shader... Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=95130 Reviewers: arsenm, tstellarAMD, mareko Subscribers: arsenm, llvm-commits, kzhuravl Differential Revision: http://reviews.llvm.org/D20839 llvm-svn: 272063 |
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| clang | ||
| clang-tools-extra | ||
| compiler-rt | ||
| debuginfo-tests | ||
| libclc | ||
| libcxx | ||
| libcxxabi | ||
| libunwind | ||
| lld | ||
| lldb | ||
| llgo | ||
| llvm | ||
| openmp | ||
| polly | ||