SuccessChanges

Summary

  1. [InstCombine] Add test cases to show bad canonicalization of bitcasts (details)
Commit 96119586c9968f3c1e56513d52956f5738cf4d26 by craig.topper
[InstCombine] Add test cases to show bad canonicalization of bitcasts
between x86_mmx and <1 x i64>.
As the test cases show, we end up with an insert/extract and a bitcast
to/from i64. x86_mmx is for some purposes conceptually a vector. We
shouldn't be adding scalar conversions around it.
Since _m64 is defined as <1 x i64> and intrinsics use x86_mmx as their
input/output these extra scalar operations prevent the X86 backend from
generating good code especially on 32-bit targets where i64 gets split.
The file was modifiedllvm/test/Transforms/InstCombine/bitcast-vec-canon.ll