From e696366e67bc9f94db16e20821115d51a3f1d41b Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper@intel.com>
Date: Thu, 22 Jun 2017 05:20:39 +0000
Subject: [PATCH] [InstCombine] Add test cases to demonstrate that and->xnor
 and or->xnor folding can create more instructions than it removed when there
 are multiple uses. NFC

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305985 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/Transforms/InstCombine/and-or-not.ll | 50 +++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/test/Transforms/InstCombine/and-or-not.ll b/test/Transforms/InstCombine/and-or-not.ll
index a8e32bd77f7..7df4568aa33 100644
--- a/test/Transforms/InstCombine/and-or-not.ll
+++ b/test/Transforms/InstCombine/and-or-not.ll
@@ -1,3 +1,4 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt < %s -instcombine -S | FileCheck %s
 
 ; PR1510
@@ -516,3 +517,52 @@ define i64 @PR32830(i64 %a, i64 %b, i64 %c) {
   ret i64 %and
 }
 
+; (~a | b) & (~b | a) --> ~(a ^ b)
+; TODO: this increases instrunction count if the pieces have additional users
+define i32 @and_to_nxor_multiuse(float %fa, float %fb) {
+; CHECK-LABEL: @and_to_nxor_multiuse(
+; CHECK-NEXT:    [[A:%.*]] = fptosi float [[FA:%.*]] to i32
+; CHECK-NEXT:    [[B:%.*]] = fptosi float [[FB:%.*]] to i32
+; CHECK-NEXT:    [[NOTA:%.*]] = xor i32 [[A]], -1
+; CHECK-NEXT:    [[NOTB:%.*]] = xor i32 [[B]], -1
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[NOTA]], [[B]]
+; CHECK-NEXT:    [[OR2:%.*]] = or i32 [[NOTB]], [[A]]
+; CHECK-NEXT:    [[TMP1:%.*]] = xor i32 [[B]], [[A]]
+; CHECK-NEXT:    [[AND:%.*]] = xor i32 [[TMP1]], -1
+; CHECK-NEXT:    [[MUL1:%.*]] = mul i32 [[OR1]], [[OR2]]
+; CHECK-NEXT:    [[MUL2:%.*]] = mul i32 [[MUL1]], [[AND]]
+; CHECK-NEXT:    ret i32 [[MUL2]]
+;
+  %a = fptosi float %fa to i32
+  %b = fptosi float %fb to i32
+  %nota = xor i32 %a, -1
+  %notb = xor i32 %b, -1
+  %or1 = or i32 %nota, %b
+  %or2 = or i32 %notb, %a
+  %and = and i32 %or1, %or2
+  %mul1 = mul i32 %or1, %or2 ; here to increase the use count of the inputs to the and
+  %mul2 = mul i32 %mul1, %and
+  ret i32 %mul2
+}
+
+; (a & b) | ~(a | b) --> ~(a ^ b)
+; TODO: this increases instrunction count if the pieces have additional users
+define i32 @or_to_nxor_multiuse(i32 %a, i32 %b) {
+; CHECK-LABEL: @or_to_nxor_multiuse(
+; CHECK-NEXT:    [[AND:%.*]] = and i32 [[A:%.*]], [[B:%.*]]
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[A]], [[B]]
+; CHECK-NEXT:    [[NOTOR:%.*]] = xor i32 [[OR]], -1
+; CHECK-NEXT:    [[TMP1:%.*]] = xor i32 [[A]], [[B]]
+; CHECK-NEXT:    [[OR2:%.*]] = xor i32 [[TMP1]], -1
+; CHECK-NEXT:    [[MUL1:%.*]] = mul i32 [[AND]], [[NOTOR]]
+; CHECK-NEXT:    [[MUL2:%.*]] = mul i32 [[MUL1]], [[OR2]]
+; CHECK-NEXT:    ret i32 [[MUL2]]
+;
+  %and = and i32 %a, %b
+  %or = or i32 %a, %b
+  %notor = xor i32 %or, -1
+  %or2 = or i32 %and, %notor
+  %mul1 = mul i32 %and, %notor ; here to increase the use count of the inputs to the or
+  %mul2 = mul i32 %mul1, %or2
+  ret i32 %mul2
+}
-- 
2.50.0