[PATCH] D128080: [SDAG] convert sub from (Pow2-1) constant into xor

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added a subscriber: foad.
RKSimon added inline comments.


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Comment at: llvm/test/CodeGen/AMDGPU/ds-sub-offset.ll:112
 ; CI-NEXT:    v_lshlrev_b32_e32 v0, 2, v0
-; CI-NEXT:    v_sub_i32_e32 v0, vcc, 0, v0
+; CI-NEXT:    v_xor_b32_e32 v0, 0xffff, v0
 ; CI-NEXT:    v_mov_b32_e32 v1, 13
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spatel wrote:
> This diff was called a code-size regression in D48529.
@foad Is this still an issue? Not sure if its relevant, but does the loss of the offset:65535 compensate?


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  https://reviews.llvm.org/D128080/new/

https://reviews.llvm.org/D128080