[llvm] [X86] Use shift+add/sub for vXi8 splat multiplies (PR #174110)

[Simon Pilgrim via llvm-commits]

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@@ -0,0 +1,1233 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=-tuning-fast-imm-vector-shift | FileCheck %s --check-prefixes=CHECK,SSE2
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=-tuning-fast-imm-vector-shift,+avx2 | FileCheck %s --check-prefixes=CHECK,AVX2
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -mattr=-tuning-fast-imm-vector-shift,+avx512f,+avx512bw | FileCheck %s --check-prefixes=CHECK,AVX512
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RKSimon wrote:

-tuning-fast-imm-vector-shift necessary?

https://github.com/llvm/llvm-project/pull/174110