[llvm] [AMDGPU] Fix lowering of canonicalize when amdgpu-ieee is disabled (PR #175867)

[Jay Foad via llvm-commits]

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jayfoad wrote:

The only way to make it less fragile is to add a predicate to the regular fcanonicalize -> v_max patterns, so that they are only used when it is safe to do so.

https://github.com/llvm/llvm-project/pull/175867