diff test/Transforms/InstCombine/narrow.ll @ 0:95c75e76d11b LLVM3.4

LLVM 3.4
author Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
date Thu, 12 Dec 2013 13:56:28 +0900
parents
children 803732b1fca8
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/Transforms/InstCombine/narrow.ll	Thu Dec 12 13:56:28 2013 +0900
@@ -0,0 +1,18 @@
+; This file contains various testcases that check to see that instcombine
+; is narrowing computations when possible.
+; RUN: opt < %s -instcombine -S | \
+; 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
+}
+