[SLP] Enable vectorization of GEP expressions.

The use cases look like the following:
    x->a = y->a + 10
    x->b = y->b + 12

llvm-svn: 210342

1 files changed, 41 insertions, 0 deletions

diff --git a/llvm/test/Transforms/SLPVectorizer/X86/gep.ll b/llvm/test/Transforms/SLPVectorizer/X86/gep.ll
new file mode 100644
index 00000000000..d6eedad9dde
--- /dev/null
+++ b/llvm/test/Transforms/SLPVectorizer/X86/gep.ll
@@ -0,0 +1,41 @@
+; RUN: opt < %s -basicaa -slp-vectorizer -S |Filecheck %s
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+
+; Test if SLP can handle GEP expressions.
+; The test perform the following action:
+;   x->first  = y->first  + 16
+;   x->second = y->second + 16
+
+; CHECK-LABEL: foo1
+; CHECK: <2 x i32*>
+define void @foo1 ({ i32*, i32* }* noalias %x, { i32*, i32* }* noalias %y) {
+  %1 = getelementptr inbounds { i32*, i32* }* %y, i64 0, i32 0
+  %2 = load i32** %1, align 8
+  %3 = getelementptr inbounds i32* %2, i64 16
+  %4 = getelementptr inbounds { i32*, i32* }* %x, i64 0, i32 0
+  store i32* %3, i32** %4, align 8
+  %5 = getelementptr inbounds { i32*, i32* }* %y, i64 0, i32 1
+  %6 = load i32** %5, align 8
+  %7 = getelementptr inbounds i32* %6, i64 16
+  %8 = getelementptr inbounds { i32*, i32* }* %x, i64 0, i32 1
+  store i32* %7, i32** %8, align 8
+  ret void
+}
+
+; Test that we don't vectorize GEP expressions if indexes are not constants.
+; We can't produce an efficient code in that case.
+; CHECK-LABEL: foo2
+; CHECK-NOT: <2 x i32*>
+define void @foo2 ({ i32*, i32* }* noalias %x, { i32*, i32* }* noalias %y, i32 %i) {
+  %1 = getelementptr inbounds { i32*, i32* }* %y, i64 0, i32 0
+  %2 = load i32** %1, align 8
+  %3 = getelementptr inbounds i32* %2, i32 %i
+  %4 = getelementptr inbounds { i32*, i32* }* %x, i64 0, i32 0
+  store i32* %3, i32** %4, align 8
+  %5 = getelementptr inbounds { i32*, i32* }* %y, i64 0, i32 1
+  %6 = load i32** %5, align 8
+  %7 = getelementptr inbounds i32* %6, i32 %i
+  %8 = getelementptr inbounds { i32*, i32* }* %x, i64 0, i32 1
+  store i32* %7, i32** %8, align 8
+  ret void
+}