[llvm] [VectorCombine] Precisely calculate the cost in foldInstExtBinop and avoid infinite loop (PR #153069)

[Simon Pilgrim via llvm-commits]

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@@ -3,24 +3,18 @@
 ; RUN: opt < %s -S -p vector-combine -mtriple=x86_64 -mattr=avx2 | FileCheck %s --check-prefixes=CHECK,AVX2
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RKSimon wrote:

drop the --check-prefixes and use the default CHECK now

https://github.com/llvm/llvm-project/pull/153069