1 files changed, 26 insertions, 0 deletions
diff --git a/test/Transforms/InstCombine/bit-tracking.ll b/test/Transforms/InstCombine/bit-tracking.ll
new file mode 100644
index 0000000..51bbc08
--- /dev/null
+++ b/test/Transforms/InstCombine/bit-tracking.ll
@@ -0,0 +1,26 @@
+; This file contains various testcases that require tracking whether bits are
+; set or cleared by various instructions.
+; RUN: opt < %s -instcombine -instcombine -S |\
+; RUN:   not grep %ELIM
+
+; Reduce down to a single XOR
+define i32 @test3(i32 %B) {
+        %ELIMinc = and i32 %B, 1                ; <i32> [#uses=1]
+        %tmp.5 = xor i32 %ELIMinc, 1            ; <i32> [#uses=1]
+        %ELIM7 = and i32 %B, -2         ; <i32> [#uses=1]
+        %tmp.8 = or i32 %tmp.5, %ELIM7          ; <i32> [#uses=1]
+        ret i32 %tmp.8
+}
+
+; Finally, a bigger case where we chain things together.  This corresponds to
+; incrementing a single-bit bitfield, which should become just an xor.
+define i32 @test4(i32 %B) {
+        %ELIM3 = shl i32 %B, 31         ; <i32> [#uses=1]
+        %ELIM4 = ashr i32 %ELIM3, 31            ; <i32> [#uses=1]
+        %inc = add i32 %ELIM4, 1                ; <i32> [#uses=1]
+        %ELIM5 = and i32 %inc, 1                ; <i32> [#uses=1]
+        %ELIM7 = and i32 %B, -2         ; <i32> [#uses=1]
+        %tmp.8 = or i32 %ELIM5, %ELIM7          ; <i32> [#uses=1]
+        ret i32 %tmp.8
+}
+