[PATCH] D31815: [Thumb1] The recently added tADCS and tSBCS pseudo-instructions were missing `Uses = [CPSR]`

[A. Skrobov via Phabricator via llvm-commits]

tyomitch added inline comments.


================
Comment at: test/CodeGen/Thumb/long.ll:234
+  ret void
+}
+
----------------
efriedma wrote:
> Please write an MIR testcase; it's difficult to understand what this is testing.
The issue in this case was that the missing implicit-use of CPSR on `tADCS` led to the last `tADDi8` being treated as dead, and eliminated (apparently by TwoAddressInstructionPass). The pass itself was doing everything right, it's just that its input was wrong.

I'm not sure what kind of MIR would make this test case easier to understand.


https://reviews.llvm.org/D31815