Avoid redundant select node in early if-conversion pass

llvm-svn: 240072

1 files changed, 41 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/AArch64/ifcvt-select.ll b/llvm/test/CodeGen/AArch64/ifcvt-select.ll
new file mode 100644
index 00000000000..4e024d963f2
--- /dev/null
+++ b/llvm/test/CodeGen/AArch64/ifcvt-select.ll
@@ -0,0 +1,41 @@
+; RUN: llc -mtriple=arm64-apple-ios -mcpu=cyclone < %s | FileCheck %s
+; Do not generate redundant select in early if-converstion pass. 
+
+define i32 @foo(i32 %a, i32 %b)  {
+entry:
+;CHECK-LABEL: foo:
+;CHECK: csinc
+;CHECK-NOT: csel
+  %sub = sub nsw i32 %b, %a
+  %cmp10 = icmp sgt i32 %a, 0
+  br i1 %cmp10, label %while.body.lr.ph, label %while.end
+
+while.body.lr.ph:
+  br label %while.body
+
+while.body:                                  
+  %j.012 = phi i32 [ %sub, %while.body.lr.ph ], [ %inc, %if.then ], [ %inc, %if.else ]
+  %i.011 = phi i32 [ %a, %while.body.lr.ph ], [ %inc2, %if.then ], [ %dec, %if.else ]
+  %cmp1 = icmp slt i32 %i.011, %j.012
+  br i1 %cmp1, label %while.end, label %while.cond
+
+while.cond:
+  %inc = add nsw i32 %j.012, 5
+  %cmp2 = icmp slt i32 %inc, %b
+  br i1 %cmp2, label %if.then, label %if.else
+
+if.then:
+  %inc2 = add nsw i32 %i.011, 1
+  br label %while.body
+
+if.else:
+  %dec = add nsw i32 %i.011, -1
+  br label %while.body
+
+while.end:
+  %j.0.lcssa = phi i32 [ %j.012, %while.body ], [ %sub, %entry ]
+  %i.0.lcssa = phi i32 [ %i.011, %while.body ], [ %a, %entry ]
+  %add = add nsw i32 %j.0.lcssa, %i.0.lcssa
+  ret i32 %add
+}
+