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0987ead525
If a collection of interconnected phi nodes is only ever loaded, stored or bitcast then we can convert the whole set to the bitcast type, potentially helping to reduce the number of register moves needed as the phi's are passed across basic block boundaries. This has to be done in CodegenPrepare as it naturally straddles basic blocks. The alorithm just looks from phi nodes, looking at uses and operands for a collection of nodes that all together are bitcast between float and integer types. We record visited phi nodes to not have to process them more than once. The whole subgraph is then replaced with a new type. Loads and Stores are bitcast to the correct type, which should then be folded into the load/store, changing it's type. This comes up in the biquad testcase due to the way MVE needs to keep values in integer registers. I have also seen it come up from aarch64 partner example code, where a complicated set of sroa/inlining produced integer phis, where float would have been a better choice. I also added undef and extract element handling which increased the potency in some cases. This adds it with an option that defaults to off, and disabled for 32bit X86 due to potential issues around canonicalizing NaNs. Differential Revision: https://reviews.llvm.org/D81827 |
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| .. | ||
| Analysis | ||
| Assembler | ||
| Bindings | ||
| Bitcode | ||
| BugPoint | ||
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| Demangle | ||
| Examples | ||
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| YAMLParser | ||
| .clang-format | ||
| CMakeLists.txt | ||
| lit.cfg.py | ||
| lit.site.cfg.py.in | ||
| TestRunner.sh | ||