1 files changed, 47 insertions, 0 deletions
diff --git a/llvm/test/Transforms/LoopStrengthReduce/X86/2011-07-20-DoubleIV.ll b/llvm/test/Transforms/LoopStrengthReduce/X86/2011-07-20-DoubleIV.ll
new file mode 100644
index 00000000000..0fc928ca9b2
--- /dev/null
+++ b/llvm/test/Transforms/LoopStrengthReduce/X86/2011-07-20-DoubleIV.ll
@@ -0,0 +1,47 @@
+; RUN: opt < %s -loop-reduce -S -mtriple=x86_64-unknown-unknown | FileCheck %s
+;
+; Test LSR's OptimizeShadowIV. Handle a floating-point IV with a
+; nonzero initial value.
+; rdar://9786536
+
+; Provide legal integer types.
+target datalayout = "n8:16:32:64"
+
+
+; First, make sure LSR doesn't crash on an empty IVUsers list.
+; CHECK-LABEL: @dummyIV(
+; CHECK-NOT: phi
+; CHECK-NOT: sitofp
+; CHECK: br
+define void @dummyIV() nounwind {
+entry:
+  br label %loop
+
+loop:
+  %i.01 = phi i32 [ -39, %entry ], [ %inc, %loop ]
+  %conv = sitofp i32 %i.01 to double
+  %inc = add nsw i32 %i.01, 1
+  br i1 undef, label %loop, label %for.end
+
+for.end:
+  unreachable
+}
+
+; Now check that the computed double constant is correct.
+; CHECK-LABEL: @doubleIV(
+; CHECK: phi double [ -3.900000e+01, %entry ]
+; CHECK: br
+define void @doubleIV() nounwind {
+entry:
+  br label %loop
+
+loop:
+  %i.01 = phi i32 [ -39, %entry ], [ %inc, %loop ]
+  %conv = sitofp i32 %i.01 to double
+  %div = fdiv double %conv, 4.000000e+01
+  %inc = add nsw i32 %i.01, 1
+  br i1 undef, label %loop, label %for.end
+
+for.end:
+  unreachable
+}