vendor/llvm/llvm-r72732

1 files changed, 18 insertions, 0 deletions

diff --git a/test/Transforms/InstCombine/narrow.ll b/test/Transforms/InstCombine/narrow.ll
new file mode 100644
index 000000000000..41106e759ce0
--- /dev/null
+++ b/test/Transforms/InstCombine/narrow.ll
@@ -0,0 +1,18 @@
+; This file contains various testcases that check to see that instcombine
+; is narrowing computations when possible.
+; RUN: llvm-as < %s | opt -instcombine | llvm-dis | \
+; RUN:    grep {ret i1 false}
+
+; test1 - Eliminating the casts in this testcase (by narrowing the AND
+; operation) allows instcombine to realize the function always returns false.
+;
+define i1 @test1(i32 %A, i32 %B) {
+        %C1 = icmp slt i32 %A, %B               ; <i1> [#uses=1]
+        %ELIM1 = zext i1 %C1 to i32             ; <i32> [#uses=1]
+        %C2 = icmp sgt i32 %A, %B               ; <i1> [#uses=1]
+        %ELIM2 = zext i1 %C2 to i32             ; <i32> [#uses=1]
+        %C3 = and i32 %ELIM1, %ELIM2            ; <i32> [#uses=1]
+        %ELIM3 = trunc i32 %C3 to i1            ; <i1> [#uses=1]
+        ret i1 %ELIM3
+}
+