[PATCH] D57553: [Fixed Point Arithmetic] Check against source value when converting during saturation

[Leonard Chan via Phabricator via cfe-commits]

leonardchan created this revision.
leonardchan added reviewers: rjmccall, ebevhan, bjope.
leonardchan added a project: clang.

When converting to a saturating fixed point type, compare against the source value instead of our container value. This allows us to not create a container, and save up to 2 instructions from extending/truncating to this container size.

These can be seen in conversions between fixed point types of the same width, but different scale or different sign.


Repository:
  rC Clang

https://reviews.llvm.org/D57553

Files:
  clang/lib/CodeGen/CGExprScalar.cpp
  clang/test/Frontend/fixed_point_add.c
  clang/test/Frontend/fixed_point_conversions.c
  clang/test/Frontend/fixed_point_sub.c

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