[llvm] [SandboxVec][Legality] Don't vectorize when instructions repeat (PR #124479)

[Sriraman Tallam via llvm-commits]

================
@@ -0,0 +1,65 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes=sandbox-vectorizer -sbvec-vec-reg-bits=1024 -sbvec-allow-non-pow2 -sbvec-passes="bottom-up-vec<>" %s -S | FileCheck %s
+
+define i32 @repeated_splat(ptr %ptr, i32 %v) #0 {
+; CHECK-LABEL: define i32 @repeated_splat(
+; CHECK-SAME: ptr [[PTR:%.*]], i32 [[V:%.*]]) {
+; CHECK-NEXT:    [[GEP0:%.*]] = getelementptr inbounds i32, ptr [[PTR]], i64 0
+; CHECK-NEXT:    [[VECL:%.*]] = load <2 x i32>, ptr [[GEP0]], align 4
+; CHECK-NEXT:    [[SPLAT:%.*]] = add i32 [[V]], 0
+; CHECK-NEXT:    [[PACK:%.*]] = insertelement <2 x i32> poison, i32 [[SPLAT]], i32 0
+; CHECK-NEXT:    [[PACK1:%.*]] = insertelement <2 x i32> [[PACK]], i32 [[SPLAT]], i32 1
+; CHECK-NEXT:    [[VEC:%.*]] = mul <2 x i32> [[VECL]], [[PACK1]]
+; CHECK-NEXT:    store <2 x i32> [[VEC]], ptr [[GEP0]], align 4
+; CHECK-NEXT:    ret i32 0
+;
+  %gep0 = getelementptr inbounds i32, ptr %ptr, i64 0
+  %gep1 = getelementptr inbounds i32, ptr %ptr, i64 1
+  %ld0 = load i32, ptr %gep0, align 4
+  %ld1 = load i32, ptr %gep1, align 4
+  %splat = add i32 %v, 0
+  %add0 = mul i32 %ld0, %splat
+  %add1 = mul i32 %ld1, %splat
+  store i32 %add0, ptr %gep0, align 4
+  store i32 %add1, ptr %gep1, align 4
+  ret i32 0
+}
+
+define i32 @repeated_partial(ptr %ptr, i32 %v) #0 {
+; CHECK-LABEL: define i32 @repeated_partial(
+; CHECK-SAME: ptr [[PTR:%.*]], i32 [[V:%.*]]) {
+; CHECK-NEXT:    [[GEP0:%.*]] = getelementptr inbounds i32, ptr [[PTR]], i64 0
+; CHECK-NEXT:    [[GEP1:%.*]] = getelementptr inbounds i32, ptr [[PTR]], i64 1
+; CHECK-NEXT:    [[GEP3:%.*]] = getelementptr inbounds i32, ptr [[PTR]], i64 3
+; CHECK-NEXT:    [[LD0:%.*]] = load i32, ptr [[GEP0]], align 4
+; CHECK-NEXT:    [[LD1:%.*]] = load i32, ptr [[GEP1]], align 4
+; CHECK-NEXT:    [[LD3:%.*]] = load i32, ptr [[GEP3]], align 4
+; CHECK-NEXT:    [[PACK:%.*]] = insertelement <4 x i32> poison, i32 [[LD0]], i32 0
+; CHECK-NEXT:    [[PACK1:%.*]] = insertelement <4 x i32> [[PACK]], i32 [[LD1]], i32 1
+; CHECK-NEXT:    [[PACK2:%.*]] = insertelement <4 x i32> [[PACK1]], i32 [[LD1]], i32 2
+; CHECK-NEXT:    [[PACK3:%.*]] = insertelement <4 x i32> [[PACK2]], i32 [[LD3]], i32 3
+; CHECK-NEXT:    [[VECL:%.*]] = load <4 x i32>, ptr [[GEP0]], align 4
+; CHECK-NEXT:    [[SPLAT:%.*]] = add i32 [[V]], 0
+; CHECK-NEXT:    [[VEC:%.*]] = mul <4 x i32> [[VECL]], [[PACK3]]
+; CHECK-NEXT:    store <4 x i32> [[VEC]], ptr [[GEP0]], align 4
+; CHECK-NEXT:    ret i32 0
+;
+  %gep0 = getelementptr inbounds i32, ptr %ptr, i64 0
+  %gep1 = getelementptr inbounds i32, ptr %ptr, i64 1
+  %gep2 = getelementptr inbounds i32, ptr %ptr, i64 2
+  %gep3 = getelementptr inbounds i32, ptr %ptr, i64 3
+  %ld0 = load i32, ptr %gep0, align 4
+  %ld1 = load i32, ptr %gep1, align 4
+  %ld2 = load i32, ptr %gep2, align 4
+  %ld3 = load i32, ptr %gep3, align 4
+  %splat = add i32 %v, 0
----------------
tmsri wrote:

Why not just remove the splat?

https://github.com/llvm/llvm-project/pull/124479