HomePhabricator

[InstCombine] canonicalize -0.0 to +0.0 in fcmp

Description

[InstCombine] canonicalize -0.0 to +0.0 in fcmp

As stated in IEEE-754 and discussed in:
https://bugs.llvm.org/show_bug.cgi?id=38086
...the sign of zero does not affect any FP compare predicate.

Known regressions were fixed with:
rL346097 (D54001)
rL346143

The transform will help reduce pattern-matching complexity to solve:
https://bugs.llvm.org/show_bug.cgi?id=39475
...as well as improve CSE and codegen (a zero constant is almost always
easier to produce than 0x80..00).

Details

Committed
spatelNov 5 2018, 9:26 AM
Parents
rL346146: [AST] Get aliased type info from an aliased TemplateSpecialization.
Branches
Unknown
Tags
Unknown