[Loop Vectorizer] Consecutive memory access - fixed and simplified

Amended consecutive memory access detection in Loop Vectorizer.
Load/Store were not handled properly without preceding GEP instruction.

Differential Revision: https://reviews.llvm.org/D20789

llvm-svn: 281853

1 files changed, 43 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopVectorize/consec_no_gep.ll b/llvm/test/Transforms/LoopVectorize/consec_no_gep.ll
new file mode 100644
index 00000000000..73cabaed773
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/consec_no_gep.ll
@@ -0,0 +1,43 @@
+;RUN: opt < %s -loop-vectorize -force-vector-width=4 -force-vector-interleave=1 -instcombine -S | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+;; Check consecutive memory access without preceding GEP instruction
+
+;  for (int i=0; i<len; i++) {
+;    *to++ = *from++;
+;  }
+
+; CHECK-LABEL: @consecutive_no_gep(
+; CHECK: vector.body
+; CHECK: %[[index:.*]] = phi i64 [ 0, %vector.ph ]
+; CHECK: getelementptr float, float* %{{.*}}, i64 %[[index]]
+; CHECK: load <4 x float>
+
+define void @consecutive_no_gep(float* noalias nocapture readonly %from, float* noalias nocapture %to, i32 %len) #0 {
+entry:
+  %cmp2 = icmp sgt i32 %len, 0
+  br i1 %cmp2, label %for.body.preheader, label %for.end
+
+for.body.preheader:                               ; preds = %entry
+  br label %for.body
+
+for.body:                                         ; preds = %for.body.preheader, %for.body
+  %i.05 = phi i32 [ %inc, %for.body ], [ 0, %for.body.preheader ]
+  %from.addr.04 = phi float* [ %incdec.ptr, %for.body ], [ %from, %for.body.preheader ]
+  %to.addr.03 = phi float* [ %incdec.ptr1, %for.body ], [ %to, %for.body.preheader ]
+  %incdec.ptr = getelementptr inbounds float, float* %from.addr.04, i64 1
+  %val = load float, float* %from.addr.04, align 4
+  %incdec.ptr1 = getelementptr inbounds float, float* %to.addr.03, i64 1
+  store float %val, float* %to.addr.03, align 4
+  %inc = add nsw i32 %i.05, 1
+  %cmp = icmp slt i32 %inc, %len
+  br i1 %cmp, label %for.body, label %for.end.loopexit
+
+for.end.loopexit:                                 ; preds = %for.body
+  br label %for.end
+
+for.end:                                          ; preds = %for.end.loopexit, %entry
+  ret void
+}