[LLE] Add missing check for unit stride

I somehow missed this.  The case in GCC (global_alloc) was similar to
the new testcase except it had an array of structs rather than a two
dimensional array.

Fixes RP26885.

llvm-svn: 263058

1 files changed, 43 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopLoadElim/non-consecutive.ll b/llvm/test/Transforms/LoopLoadElim/non-consecutive.ll
new file mode 100644
index 00000000000..43751a8ff60
--- /dev/null
+++ b/llvm/test/Transforms/LoopLoadElim/non-consecutive.ll
@@ -0,0 +1,43 @@
+; RUN: opt -loop-load-elim -S < %s | FileCheck %s
+
+; The accesses to A are independent here but LAA reports it as a loop-carried
+; forward dependence.  Check that we don't perform st->ld forwarding between
+; them.
+;
+;   for (unsigned i = 0; i < 100; i++) {
+;     A[i][1] = B[i] + 2;
+;     C[i] = A[i][0] * 2;
+;   }
+
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @f([2 x i32]* noalias %A, i32* noalias %B, i32* noalias %C, i64 %N) {
+
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %for.body ]
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+
+  %A1idx = getelementptr inbounds [2 x i32], [2 x i32]* %A, i64 %indvars.iv, i32 1
+  %Bidx = getelementptr inbounds i32, i32* %B, i64 %indvars.iv
+  %Cidx = getelementptr inbounds i32, i32* %C, i64 %indvars.iv
+  %A0idx = getelementptr inbounds [2 x i32], [2 x i32]* %A, i64 %indvars.iv, i32 0
+
+  %b = load i32, i32* %Bidx, align 4
+  %a_p1 = add i32 %b, 2
+  store i32 %a_p1, i32* %A1idx, align 4
+
+; CHECK: %a = load i32, i32* %A0idx, align 4
+  %a = load i32, i32* %A0idx, align 4
+; CHECK: %c = mul i32 %a, 2
+  %c = mul i32 %a, 2
+  store i32 %c, i32* %Cidx, align 4
+
+  %exitcond = icmp eq i64 %indvars.iv.next, %N
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret void
+}