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

[Jasmine Tang via llvm-commits]

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@@ -0,0 +1,88 @@
+; 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_sext_1(<8 x i16> %a, <8 x i16> %b) {
+; CHECK-LABEL: dot_sext_1:
+; CHECK:         .functype dot_sext_1 (v128, v128) -> (v128)
+; CHECK-NEXT:  # %bb.0:
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 1
+; CHECK-NEXT:    i32x4.dot_i16x8_s
+; CHECK-NEXT:    # fallthrough-return
+  %sext1 = sext <8 x i16> %a to <8 x i32>
+  %sext2 = sext <8 x i16> %b to <8 x i32>
+  %mul = mul <8 x i32> %sext1, %sext2
+  %shuffle1 = shufflevector <8 x i32> %mul, <8 x i32> poison, <4 x i32> <i32 0, i32 2, i32 4, i32 6>
+  %shuffle2 = shufflevector <8 x i32> %mul, <8 x i32> poison, <4 x i32> <i32 1, i32 3, i32 5, i32 7>
+  %res = add <4 x i32> %shuffle1, %shuffle2
+  ret <4 x i32> %res
+}
+
+
+define <4 x i32> @dot_sext_2(<8 x i16> %a, <8 x i16> %b) {
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badumbatish wrote:

yep works perfectly!

<img width="837" height="213" alt="Screenshot 2025-08-07 at 11 58 42 AM" src="https://github.com/user-attachments/assets/db75a579-1f57-402a-bbdc-3800ad0a1f73" />


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