[PATCH] D122875: [DAGCombiner] Scalarize extend/truncate for splat vector.

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


================
Comment at: llvm/test/CodeGen/RISCV/rvv/vwsub-sdnode.ll:548
+; CHECK64-NEXT:    vsetvli a1, zero, e64, m8, ta, mu
+; CHECK64-NEXT:    vsub.vx v8, v8, a0
+; CHECK64-NEXT:    ret
----------------
RKSimon wrote:
> regressions?
RISC-V is weak on scalar zero extend in the base ISA. We get a zext.w operation with the Zba extension. On the vector side a widening vwsub.wx is probably more expensive than a non-widening vsub.vx


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  https://reviews.llvm.org/D122875/new/

https://reviews.llvm.org/D122875