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bac11518cd
Previously, LiveRegUnits was assuming that if a block has no successors and does not return, then no registers are live at the end of it (because the end of the block is unreachable). This was causing the register scavenger to use callee-saved registers to materialise stack frame addresses without saving them in the prologue. This would normally be fine, because the end of the block is unreachable, but this is not legal if the block ends by throwing a C++ exception. If this happens, the scratch register will be modified, but its previous value won't be preserved, so it doesn't get restored by the exception unwinder. Differential revision: https://reviews.llvm.org/D57381 llvm-svn: 352844
The LLVM Compiler Infrastructure
This directory and its subdirectories contain source code for LLVM, a toolkit for the construction of highly optimized compilers, optimizers, and runtime environments.