[llvm] [HLSL] Move FNeg legalization to the DXILLegalization pass (PR #140942)

[Farzon Lotfi via llvm-commits]

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@@ -0,0 +1,23 @@
+; RUN: opt -S -passes='dxil-legalize' -mtriple=dxil-pc-shadermodel6.3-library %s | FileCheck %s
+
+define float @negateF(float %x) {
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farzonl wrote:

were there no tests dependent on  the `DXILPrepare` pass for fneg to fsub? I would expect if their were they would be failing now.

https://github.com/llvm/llvm-project/pull/140942