Don't always:
cast (select (cmp x, y), z, C) --> select (cmp x, y), (cast z), C'
This is something that came up as far back as D26556, and I lost track of it.
I suspect that this transform is part of the underlying problem that is
inspiring some of the recent proposals that seek to match larger patterns
that include a cast op. Even if that's not true, this transform causes
problems for codegen (particularly with vector types).
A transform to actively match the size of cmp and select operand sizes should
follow. This patch just removes the harmful canonicalization in the other
direction.
Differential Revision: https://reviews.llvm.org/D47163
llvm-svn: 333611
In all cases, we're pulling the cast above the select.
That's not a good canonicalization if we're creating
a select that then mismatches the operand size of its
condition.
llvm-svn: 332883
Sanjay Patel