[clang] [llvm] [mlir] Remove the `x86_mmx` IR type. (PR #98505)

[James Y Knight via cfe-commits]

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@@ -1,9 +0,0 @@
-; RUN: llvm-as < %s | llvm-dis | FileCheck %s
-; RUN: verify-uselistorder %s
-; Basic smoke test for x86_mmx type.
-
-; CHECK: define x86_mmx @sh16
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jyknight wrote:

The compatibility* tests already cover bitcode-upgrade, and now the IR text "x86_mmx" is simply a textual-IR _parse-time_ alias for <1 x i64>, so this test isn't really testing anything, anymore. 

I expect to remove the textual-IR parse-time alias in subsequent cleanup, too -- the main reason for it right now is just to avoid the noise in test updates at the same time as the real changes.

https://github.com/llvm/llvm-project/pull/98505