1 files changed, 46 insertions, 0 deletions
diff --git a/llvm/test/Transforms/InstCombine/all-bits-shift.ll b/llvm/test/Transforms/InstCombine/all-bits-shift.ll
new file mode 100644
index 00000000000..b9eb19cf2ad
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/all-bits-shift.ll
@@ -0,0 +1,46 @@
+; RUN: opt -S -instcombine < %s | FileCheck %s
+; RUN: opt -S -instsimplify < %s | FileCheck %s
+target datalayout = "E-m:e-i64:64-n32:64"
+target triple = "powerpc64-unknown-linux-gnu"
+
+@d = global i32 15, align 4
+@b = global i32* @d, align 8
+@a = common global i32 0, align 4
+
+; Function Attrs: nounwind
+define signext i32 @main() #1 {
+entry:
+  %0 = load i32*, i32** @b, align 8
+  %1 = load i32, i32* @a, align 4
+  %lnot = icmp eq i32 %1, 0
+  %lnot.ext = zext i1 %lnot to i32
+  %shr.i = lshr i32 2072, %lnot.ext
+  %call.lobit = lshr i32 %shr.i, 7
+  %2 = and i32 %call.lobit, 1
+  %3 = load i32, i32* %0, align 4
+  %or = or i32 %2, %3
+  store i32 %or, i32* %0, align 4
+  %4 = load i32, i32* @a, align 4
+  %lnot.1 = icmp eq i32 %4, 0
+  %lnot.ext.1 = zext i1 %lnot.1 to i32
+  %shr.i.1 = lshr i32 2072, %lnot.ext.1
+  %call.lobit.1 = lshr i32 %shr.i.1, 7
+  %5 = and i32 %call.lobit.1, 1
+  %or.1 = or i32 %5, %or
+  store i32 %or.1, i32* %0, align 4
+  ret i32 %or.1
+
+; Check that both InstCombine and InstSimplify can use computeKnownBits to
+; realize that:
+;   ((2072 >> (L == 0)) >> 7) & 1
+; is always zero.
+
+; CHECK-LABEL: @main
+; CHECK: %[[V1:[0-9]+]] = load i32*, i32** @b, align 8
+; CHECK: %[[V2:[0-9]+]] = load i32, i32* %[[V1]], align 4
+; CHECK: ret i32 %[[V2]]
+}
+
+attributes #0 = { nounwind readnone }
+attributes #1 = { nounwind }
+