[clang-tools-extra] [llvm] [RISCV][Zba] Optimize mul with SH*ADD (PR #68144)

[Craig Topper via cfe-commits]

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@@ -983,6 +983,1299 @@ define i64 @mul81(i64 %a) {
   ret i64 %c
 }
 
+
+define i64 @mul153(i64 %a) {
+; RV64I-LABEL: mul153:
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topperc wrote:

llvm-mca doesn't think this is an improvement for sifive-x280 https://godbolt.org/z/6ahP11xrq

https://github.com/llvm/llvm-project/pull/68144