[PATCH] D149888: [RISCV] Add tests for unprofitable SLP vectorization due to GEP

[Luke Lau via Phabricator via llvm-commits]

luke updated this revision to Diff 535842.
luke added a comment.

Undo accidental diff update: apologies for the noise.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D149888/new/

https://reviews.llvm.org/D149888

Files:
  llvm/test/Transforms/SLPVectorizer/RISCV/gep.ll


Index: llvm/test/Transforms/SLPVectorizer/RISCV/gep.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/SLPVectorizer/RISCV/gep.ll
@@ -0,0 +1,82 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=slp-vectorizer -mtriple=riscv64 -mattr=+v \
+; RUN: -riscv-v-slp-max-vf=0 -S | FileCheck %s
+
+; FIXME: This should not be vectorized, as the cost of computing the
+; offsets nullifies the benefits of vectorizing:
+;
+; copy_with_offset_v2i8:
+;         addi    a0, a0, 8
+;         vsetivli        zero, 2, e8, mf8, ta, ma
+;         vle8.v  v8, (a0)
+;         addi    a1, a1, 16
+;         vse8.v  v8, (a1)
+;         ret
+;
+; Compared to the scalar version where the offsets can be folded into the
+; addressing mode:
+;
+; copy_with_offset_v2i8:
+;         lbu     a2, 8(a0)
+;         lbu     a0, 9(a0)
+;         sb      a2, 16(a1)
+;         sb      a0, 17(a1)
+;	  ret
+
+define void @copy_with_offset_v2i8(ptr noalias %p, ptr noalias %q) {
+; CHECK-LABEL: @copy_with_offset_v2i8(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[P1:%.*]] = getelementptr i8, ptr [[P:%.*]], i32 8
+; CHECK-NEXT:    [[Q1:%.*]] = getelementptr i8, ptr [[Q:%.*]], i32 16
+; CHECK-NEXT:    [[TMP0:%.*]] = load <2 x i8>, ptr [[P1]], align 1
+; CHECK-NEXT:    store <2 x i8> [[TMP0]], ptr [[Q1]], align 1
+; CHECK-NEXT:    ret void
+;
+entry:
+  %p1 = getelementptr i8, ptr %p, i32 8
+  %x1 = load i8, ptr %p1
+  %q1 = getelementptr i8, ptr %q, i32 16
+  store i8 %x1, ptr %q1
+
+  %p2 = getelementptr i8, ptr %p, i32 9
+  %x2 = load i8, ptr %p2
+  %q2 = getelementptr i8, ptr %q, i32 17
+  store i8 %x2, ptr %q2
+
+  ret void
+}
+
+; This on the other hand, should be vectorized as the vector savings outweigh
+; the GEP costs.
+define void @copy_with_offset_v4i8(ptr noalias %p, ptr noalias %q) {
+; CHECK-LABEL: @copy_with_offset_v4i8(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[P1:%.*]] = getelementptr i8, ptr [[P:%.*]], i32 8
+; CHECK-NEXT:    [[Q1:%.*]] = getelementptr i8, ptr [[Q:%.*]], i32 16
+; CHECK-NEXT:    [[TMP0:%.*]] = load <4 x i8>, ptr [[P1]], align 1
+; CHECK-NEXT:    store <4 x i8> [[TMP0]], ptr [[Q1]], align 1
+; CHECK-NEXT:    ret void
+;
+entry:
+  %p1 = getelementptr i8, ptr %p, i32 8
+  %x1 = load i8, ptr %p1
+  %q1 = getelementptr i8, ptr %q, i32 16
+  store i8 %x1, ptr %q1
+
+  %p2 = getelementptr i8, ptr %p, i32 9
+  %x2 = load i8, ptr %p2
+  %q2 = getelementptr i8, ptr %q, i32 17
+  store i8 %x2, ptr %q2
+
+  %p3 = getelementptr i8, ptr %p, i32 10
+  %x3 = load i8, ptr %p3
+  %q3 = getelementptr i8, ptr %q, i32 18
+  store i8 %x3, ptr %q3
+
+  %p4 = getelementptr i8, ptr %p, i32 11
+  %x4 = load i8, ptr %p4
+  %q4 = getelementptr i8, ptr %q, i32 19
+  store i8 %x4, ptr %q4
+
+  ret void
+}


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