[llvm] [WebAssembly] Add fold support for dot (PR #151775)

[Sam Parker via llvm-commits]

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@@ -0,0 +1,21 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc < %s -mattr=+simd128 | FileCheck %s
+
+target triple = "wasm32-unknown-unknown"
+define <4 x i32> @dot(<8 x i16> %a, <8 x i16> %b) {
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sparker-arm wrote:

Please add some negative tests, just so we can be sure a `zext` isn't slipping in, or the wrong kind of shuffle.

https://github.com/llvm/llvm-project/pull/151775