Jann Horn 91c9dee3fb [CodeGenPrepare] Eliminate llvm.expect before removing empty blocks ...

CodeGenPrepare currently first removes empty blocks, then in a loop
performs other optimizations. One of those optimizations is the removal
of call instructions that invoke @llvm.assume, which can create new
empty blocks.

This means that when a branch only contains a call to __builtin_assume(),
the empty branch will survive into MIR, and will then only be
half-removed by MIR-level optimizations (e.g. removing the branch but
leaving the condition intact).

Fix it by eliminating @llvm.expect builtin calls before removing empty
blocks.

Reviewed By: bkramer

Differential Revision: https://reviews.llvm.org/D97848

2021-03-04 14:48:26 +01:00

304 KiB

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