[PATCH] D89956: [AArch64] Redundant masks in downcast long multiply

[Dave Green via Phabricator via llvm-commits]

dmgreen added a comment.

Something like https://godbolt.org/z/q376ob maybe?



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Comment at: llvm/lib/Target/AArch64/AArch64InstrInfo.td:1478
+          (SMADDLrrr (EXTRACT_SUBREG $Rn, sub_32), (EXTRACT_SUBREG $Rm, sub_32), XZR)>;
+def : Pat<(i64 (mul (sext_inreg GPR64:$Rn, i32), (sext GPR64:$Rm))),
+          (SMADDLrrr (EXTRACT_SUBREG $Rn, sub_32), (EXTRACT_SUBREG $Rm, sub_32), XZR)>;
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GPR32 I think, for the sext input. And then the output can use the GPR32 directly. Like the SMADDLrrr pattern below.


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https://reviews.llvm.org/D89956