1 files changed, 40 insertions, 0 deletions
diff --git a/test/CodeGen/X86/avoid_complex_am.ll b/test/CodeGen/X86/avoid_complex_am.ll
new file mode 100644
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+++ b/test/CodeGen/X86/avoid_complex_am.ll
@@ -0,0 +1,40 @@
+; RUN: opt -S -loop-reduce < %s | FileCheck %s
+; Complex addressing mode are costly.
+; Make loop-reduce prefer unscaled accesses.
+; On X86, reg1 + 1*reg2 has the same cost as reg1 + 8*reg2.
+; Therefore, LSR currently prefers to fold as much computation as possible
+; in the addressing mode.
+; <rdar://problem/16730541>
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx"
+
+define void @mulDouble(double* nocapture %a, double* nocapture %b, double* nocapture %c) {
+; CHECK: @mulDouble
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+; CHECK: [[IV:%[^ ]+]] = phi i64 [ [[IVNEXT:%[^,]+]], %for.body ], [ 0, %entry ]
+; Only one induction variable should have been generated.
+; CHECK-NOT: phi
+  %indvars.iv = phi i64 [ 1, %entry ], [ %indvars.iv.next, %for.body ]
+  %tmp = add nsw i64 %indvars.iv, -1
+  %arrayidx = getelementptr inbounds double* %b, i64 %tmp
+  %tmp1 = load double* %arrayidx, align 8
+; The induction variable should carry the scaling factor: 1.
+; CHECK: [[IVNEXT]] = add nuw nsw i64 [[IV]], 1
+  %indvars.iv.next = add i64 %indvars.iv, 1
+  %arrayidx2 = getelementptr inbounds double* %c, i64 %indvars.iv.next
+  %tmp2 = load double* %arrayidx2, align 8
+  %mul = fmul double %tmp1, %tmp2
+  %arrayidx4 = getelementptr inbounds double* %a, i64 %indvars.iv
+  store double %mul, double* %arrayidx4, align 8
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+; Comparison should be 19 * 1 = 19.
+; CHECK: icmp eq i32 {{%[^,]+}}, 19
+  %exitcond = icmp eq i32 %lftr.wideiv, 20
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.body
+  ret void
+}