tree bc5153c19861201adf7613b02df2269f72f15071
parent 0774188da4bb970b22e302aa24be64bf27f8ce05
author Ben Clayton <bclayton@google.com> 1585818731 +0100
committer Ben Clayton <bclayton@google.com> 1585841117 +0000

Change for loops to use const refs, per performance-for-range-copy clang-tidy.

This CL optimizes C++11 range-based for loops where the variable is copied in each iteration but it would suffice to obtain it by const reference.  This is only applied to loop variables of types that are expensive to copy which means they are not trivially copyable or have a non-trivial copy constructor or destructor.

To ensure that it is safe to replace the copy with a const reference the following heuristic is employed:
  The loop variable is const qualified.
  The loop variable is not const, but only const methods or operators are invoked on it, or it is used as const reference or value argument in constructors or function calls.

See cl/304001946 for more information.

Bug: None.
Change-Id: Idbb5a0dbf19c6dccb16a0d525900aa99419a8527
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/43368
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Ben Clayton <bclayton@google.com>