forked from OSchip/llvm-project
95d9ccb2a0
In r263618, JumpThreading learned to look trough simple cast instructions, but only if the source of those cast instructions was a phi/cmp i1 (in an effort to limit compile time effects). I think this condition is too restrictive. For switches with limited value range, InstCombine will readily introduce an extra trunc instruction to a smaller integer type (e.g. from i8 to i2), leaving us in the somewhat perverse situation that jump-threading would work before running instcombine, but not after. Since instcombine produces this pattern, I think we need to consider it canonical and support it in JumpThreading. In general, for limiting recursion, I think the existing restriction to phi and cmp nodes should be sufficient to avoid looking through unprofitable chains of instructions. Patch by Keno Fischer! Differential Revision: https://reviews.llvm.org/D42262 llvm-svn: 327150 |
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| .. | ||
| AggressiveInstCombine | ||
| Coroutines | ||
| Hello | ||
| IPO | ||
| InstCombine | ||
| Instrumentation | ||
| ObjCARC | ||
| Scalar | ||
| Utils | ||
| Vectorize | ||
| CMakeLists.txt | ||
| LLVMBuild.txt | ||