1 files changed, 58 insertions, 0 deletions
diff --git a/test/Transforms/InstCombine/compare-signs.ll b/test/Transforms/InstCombine/compare-signs.ll
new file mode 100644
index 0000000..f8e4911
--- /dev/null
+++ b/test/Transforms/InstCombine/compare-signs.ll
@@ -0,0 +1,58 @@
+; RUN: opt %s -instcombine -S | FileCheck %s
+; PR5438
+
+; TODO: This should also optimize down.
+;define i32 @test1(i32 %a, i32 %b) nounwind readnone {
+;entry:
+;        %0 = icmp sgt i32 %a, -1        ; <i1> [#uses=1]
+;        %1 = icmp slt i32 %b, 0         ; <i1> [#uses=1]
+;        %2 = xor i1 %1, %0              ; <i1> [#uses=1]
+;        %3 = zext i1 %2 to i32          ; <i32> [#uses=1]
+;        ret i32 %3
+;}
+
+; TODO: This optimizes partially but not all the way.
+;define i32 @test2(i32 %a, i32 %b) nounwind readnone {
+;entry:
+;        %0 = and i32 %a, 8            ;<i32>  [#uses=1]
+;        %1 = and i32 %b, 8            ;<i32>  [#uses=1]
+;        %2 = icmp eq i32 %0, %1         ;<i1>  [#uses=1]
+;        %3 = zext i1 %2 to i32          ;<i32>  [#uses=1]
+;        ret i32 %3
+;}
+
+define i32 @test3(i32 %a, i32 %b) nounwind readnone {
+; CHECK: @test3
+entry:
+; CHECK: xor i32 %a, %b
+; CHECK: lshr i32 %0, 31
+; CHECK: xor i32 %1, 1
+        %0 = lshr i32 %a, 31            ; <i32> [#uses=1]
+        %1 = lshr i32 %b, 31            ; <i32> [#uses=1]
+        %2 = icmp eq i32 %0, %1         ; <i1> [#uses=1]
+        %3 = zext i1 %2 to i32          ; <i32> [#uses=1]
+        ret i32 %3
+; CHECK-NOT: icmp
+; CHECK-NOT: zext
+; CHECK: ret i32 %2
+}
+
+; Variation on @test3: checking the 2nd bit in a situation where the 5th bit
+; is one, not zero.
+define i32 @test3i(i32 %a, i32 %b) nounwind readnone {
+; CHECK: @test3i
+entry:
+; CHECK: xor i32 %a, %b
+; CHECK: lshr i32 %0, 31
+; CHECK: xor i32 %1, 1
+        %0 = lshr i32 %a, 29            ; <i32> [#uses=1]
+        %1 = lshr i32 %b, 29            ; <i32> [#uses=1]
+        %2 = or i32 %0, 35
+        %3 = or i32 %1, 35
+        %4 = icmp eq i32 %2, %3         ; <i1> [#uses=1]
+        %5 = zext i1 %4 to i32          ; <i32> [#uses=1]
+        ret i32 %5
+; CHECK-NOT: icmp
+; CHECK-NOT: zext
+; CHECK: ret i32 %2
+}