[PATCH] D154919: [LoongArch] Implement isSExtCheaperThanZExt

[WÁNG Xuěruì via Phabricator via llvm-commits]

xen0n added inline comments.


================
Comment at: llvm/test/CodeGen/LoongArch/ir-instruction/br.ll:29-30
 ; LA64:       # %bb.0:
-; LA64-NEXT:    ld.wu $a2, $a1, 0
-; LA64-NEXT:    bstrpick.d $a0, $a0, 31, 0
+; LA64-NEXT:    ld.w $a2, $a1, 0
+; LA64-NEXT:    addi.w $a0, $a0, 0
 ; LA64-NEXT:    beq $a2, $a0, .LBB1_2
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hev wrote:
> Future patches will utilize the W instruction, thereby eliminating unnecessary sign extensions.
Mind explaining a bit what's the codegen you intended? Right now I couldn't think of a `*.w` instruction that would allow us to reduce this basic block any further.


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https://reviews.llvm.org/D154919