[llvm] [AMDGPU] Recognise bitmask operations as srcmods (PR #149110)

[via llvm-commits]

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@@ -3036,6 +3036,36 @@ bool AMDGPUDAGToDAGISel::SelectVOP3ModsImpl(SDValue In, SDValue &Src,
     Src = Src.getOperand(0);
   }
 
+  // Convert various sign-bit masks to src mods. Currently disabled for 16-bit
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LU-JOHN wrote:

But, if we apply this to (xor 0x0000.0001, 0x8000.0000) => (neg 0x0000.0001) == 0xFFFF.FFFF which isn't valid.

https://github.com/llvm/llvm-project/pull/149110