RFR: 8308340: C2: Idealize Fma nodes [v2]

[Fei Gao]

On Wed, 21 Jun 2023 18:10:26 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

> Check for `UseFMA` should be moved from `c2compiler.cpp` to `Matcher::match_rule_supported` in `.ad` files. I see we have such check for Fma vectors in `x86.ad` but not for scalars. Similar issue exist for other platforms.

@vnkozlov Thanks for your review! I updated it in the latest commit.

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PR Comment: https://git.openjdk.org/jdk/pull/14576#issuecomment-1608699766