test for and-tst peephole optimization

documents the status-quo with its opportunities

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113838 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/CodeGen/ARM/arm-and-tst-peephole.ll b/test/CodeGen/ARM/arm-and-tst-peephole.ll
new file mode 100644 (file)
index 0000000..77bc9ee
--- /dev/null
+++ b/test/CodeGen/ARM/arm-and-tst-peephole.ll
@@ -0,0 +1,58 @@
+; RUN: llc < %s -mtriple=arm-apple-darwin | FileCheck %s
+; RUN: llc < %s -mtriple=thumbv6-apple-darwin | FileCheck -check-prefix=T2 %s
+
+%struct.Foo = type { i8* }
+
+define %struct.Foo* @_ZN3Foo7collectEj(%struct.Foo* %this, i32 %acc) nounwind readonly align 2 {
+entry:
+  %scevgep = getelementptr %struct.Foo* %this, i32 1
+  br label %tailrecurse
+
+tailrecurse:                                      ; preds = %sw.bb, %entry
+  %lsr.iv2 = phi %struct.Foo* [ %scevgep3, %sw.bb ], [ %scevgep, %entry ]
+  %lsr.iv = phi i32 [ %lsr.iv.next, %sw.bb ], [ 1, %entry ]
+  %acc.tr = phi i32 [ %or, %sw.bb ], [ %acc, %entry ]
+  %lsr.iv24 = bitcast %struct.Foo* %lsr.iv2 to i8**
+  %scevgep5 = getelementptr i8** %lsr.iv24, i32 -1
+  %tmp2 = load i8** %scevgep5
+  %0 = ptrtoint i8* %tmp2 to i32
+
+; CHECK:      and lr, r12, #3
+; CHECK-NEXT: tst r12, #3
+; CHECK-NEXT: beq LBB0_4
+
+; T2:      movs r5, #3
+; T2-NEXT: mov r6, r4
+; T2-NEXT: ands r6, r5
+; T2-NEXT: tst r4, r5
+; T2-NEXT: beq LBB0_5
+
+  %and = and i32 %0, 3
+  %tst = icmp eq i32 %and, 0
+  br i1 %tst, label %sw.bb, label %tailrecurse.switch
+
+tailrecurse.switch:                               ; preds = %tailrecurse
+  switch i32 %and, label %sw.epilog [
+    i32 1, label %sw.bb
+    i32 3, label %sw.bb6
+    i32 2, label %sw.bb8
+  ]
+
+sw.bb:                                            ; preds = %tailrecurse.switch, %tailrecurse
+  %shl = shl i32 %acc.tr, 1
+  %or = or i32 %and, %shl
+  %lsr.iv.next = add i32 %lsr.iv, 1
+  %scevgep3 = getelementptr %struct.Foo* %lsr.iv2, i32 1
+  br label %tailrecurse
+
+sw.bb6:                                           ; preds = %tailrecurse.switch
+  ret %struct.Foo* %lsr.iv2
+
+sw.bb8:                                           ; preds = %tailrecurse.switch
+  %tmp1 = add i32 %acc.tr, %lsr.iv
+  %add.ptr11 = getelementptr inbounds %struct.Foo* %this, i32 %tmp1
+  ret %struct.Foo* %add.ptr11
+
+sw.epilog:                                        ; preds = %tailrecurse.switch
+  ret %struct.Foo* undef
+}