instcombine: fold (x & y) | (~x & z) and (x & y) ^ (~x & z) into ((y ^ z) & x) ^ z which is one instruction shorter. (PR6773)

before:
  %and = and i32 %y, %x
  %neg = xor i32 %x, -1
  %and4 = and i32 %z, %neg
  %xor = xor i32 %and4, %and

after:
  %xor1 = xor i32 %z, %y
  %and2 = and i32 %xor1, %x
  %xor = xor i32 %and2, %z


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108136 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 28 insertions, 0 deletions

diff --git a/test/Transforms/InstCombine/or.ll b/test/Transforms/InstCombine/or.ll
index c3526b77f6..86fca14dbd 100644
--- a/test/Transforms/InstCombine/or.ll
+++ b/test/Transforms/InstCombine/or.ll
@@ -350,3 +350,17 @@ define <4 x i32> @test32(<4 x i1> %and.i1352, <4 x i32> %vecinit6.i176, <4 x i32
 ; CHECK: or <4 x i32> %and.i, %and.i129
 }
 
+; PR6773
+define i32 @test33(i32 %x, i32 %y, i32 %z) nounwind readnone {
+  %and = and i32 %y, %x
+  %not = xor i32 %x, -1
+  %and2 = and i32 %z, %not
+  %xor = xor i32 %and2, %and
+  ret i32 %xor
+; CHECK: @test33
+; CHECK: xor i32
+; CHECK: and i32
+; CHECK: xor i32
+; CHECK: ret i32
+}
+
diff --git a/test/Transforms/InstCombine/xor2.ll b/test/Transforms/InstCombine/xor2.ll
index 67f05efa23..27ce3bff47 100644
--- a/test/Transforms/InstCombine/xor2.ll
+++ b/test/Transforms/InstCombine/xor2.ll
@@ -51,3 +51,17 @@ define i32 @test4(i32 %A, i32 %B) {
 ; CHECK: %1 = ashr i32 %A, %B
 ; CHECK: ret i32 %1
 }
+
+; PR6773
+define i32 @test5(i32 %x, i32 %y, i32 %z) nounwind readnone {
+  %and = and i32 %y, %x
+  %not = xor i32 %x, -1
+  %and2 = and i32 %z, %not
+  %or = or i32 %and2, %and
+  ret i32 %or
+; CHECK: @test5
+; CHECK: xor i32
+; CHECK: and i32
+; CHECK: xor i32
+; CHECK: ret i32
+}