[llvm] [InstCombine] Add one-use limitation to box multiply fold (PR #72876)

[via llvm-commits]

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@@ -177,6 +177,7 @@ define i64 @mul_full_64_variant2(i64 %a, i64 %b, ptr nocapture %rhi) {
   ret i64 %add27
 }
 
+; Negative test case for mul_fold function: MUL7 is used in more than one place
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shaojingzhi wrote:

Sorry I'm a little confused, what kind of test case do you mean? Could you give me a pattern? I think in this case shl would not be used in more than one place, the only usage is in calculating crosssum of higher half bits.

https://github.com/llvm/llvm-project/pull/72876