From d2f13b62d97bd48af999ac47058759f2a92123ce Mon Sep 17 00:00:00 2001
From: Sanjay Patel <spatel@rotateright.com>
Date: Mon, 1 May 2017 14:52:17 +0000
Subject: [PATCH] [InstCombine] add multi-use variants for DeMorgan folds; NFC

llvm-svn: 301802
---
 llvm/test/Transforms/InstCombine/demorgan.ll | 128 +++++++++++++++++++
 1 file changed, 128 insertions(+)

diff --git a/llvm/test/Transforms/InstCombine/demorgan.ll b/llvm/test/Transforms/InstCombine/demorgan.ll
index d2aeb9c957a0..d98dddb92754 100644
--- a/llvm/test/Transforms/InstCombine/demorgan.ll
+++ b/llvm/test/Transforms/InstCombine/demorgan.ll
@@ -242,6 +242,134 @@ define i8 @demorgan_nor(i8 %A, i8 %B) {
   ret i8 %notc
 }
 
+; ~(~A | B) --> (A & ~B) - what if we use one of the intermediate results?
+
+define i8 @demorgan_nor_use2a(i8 %A, i8 %B) {
+; CHECK-LABEL: @demorgan_nor_use2a(
+; CHECK-NEXT:    [[NOTA:%.*]] = xor i8 %A, -1
+; CHECK-NEXT:    [[USE2A:%.*]] = mul i8 [[NOTA]], 23
+; CHECK-NEXT:    [[B_NOT:%.*]] = xor i8 %B, -1
+; CHECK-NEXT:    [[NOTC:%.*]] = and i8 [[B_NOT]], %A
+; CHECK-NEXT:    [[R:%.*]] = sdiv i8 [[NOTC]], [[USE2A]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %nota = xor i8 %A, -1
+  %use2a = mul i8 %nota, 23
+  %c = or i8 %nota, %B
+  %notc = xor i8 %c, -1
+  %r = sdiv i8 %notc, %use2a
+  ret i8 %r
+}
+
+; ~(~A | B) --> (A & ~B) - what if we use one of the intermediate results?
+
+define i8 @demorgan_nor_use2b(i8 %A, i8 %B) {
+; CHECK-LABEL: @demorgan_nor_use2b(
+; CHECK-NEXT:    [[USE2B:%.*]] = mul i8 %B, 23
+; CHECK-NEXT:    [[B_NOT:%.*]] = xor i8 %B, -1
+; CHECK-NEXT:    [[NOTC:%.*]] = and i8 [[B_NOT]], %A
+; CHECK-NEXT:    [[R:%.*]] = sdiv i8 [[NOTC]], [[USE2B]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %use2b = mul i8 %B, 23
+  %nota = xor i8 %A, -1
+  %c = or i8 %nota, %B
+  %notc = xor i8 %c, -1
+  %r = sdiv i8 %notc, %use2b
+  ret i8 %r
+}
+
+; ~(~A | B) --> (A & ~B) - what if we use one of the intermediate results?
+
+define i8 @demorgan_nor_use2c(i8 %A, i8 %B) {
+; CHECK-LABEL: @demorgan_nor_use2c(
+; CHECK-NEXT:    [[NOTA:%.*]] = xor i8 %A, -1
+; CHECK-NEXT:    [[C:%.*]] = or i8 [[NOTA]], %B
+; CHECK-NEXT:    [[USE2C:%.*]] = mul i8 [[C]], 23
+; CHECK-NEXT:    [[B_NOT:%.*]] = xor i8 %B, -1
+; CHECK-NEXT:    [[NOTC:%.*]] = and i8 [[B_NOT]], %A
+; CHECK-NEXT:    [[R:%.*]] = sdiv i8 [[NOTC]], [[USE2C]]
+; CHECK-NEXT:    ret i8 [[R]]
+;
+  %nota = xor i8 %A, -1
+  %c = or i8 %nota, %B
+  %use2c = mul i8 %c, 23
+  %notc = xor i8 %c, -1
+  %r = sdiv i8 %notc, %use2c
+  ret i8 %r
+}
+
+; ~(~A | B) --> (A & ~B) - what if we use two of the intermediate results?
+
+define i8 @demorgan_nor_use2ab(i8 %A, i8 %B) {
+; CHECK-LABEL: @demorgan_nor_use2ab(
+; CHECK-NEXT:    [[USE2B:%.*]] = mul i8 %B, 23
+; CHECK-NEXT:    [[NOTA:%.*]] = xor i8 %A, -1
+; CHECK-NEXT:    [[USE2A:%.*]] = mul i8 [[NOTA]], 17
+; CHECK-NEXT:    [[B_NOT:%.*]] = xor i8 %B, -1
+; CHECK-NEXT:    [[NOTC:%.*]] = and i8 [[B_NOT]], %A
+; CHECK-NEXT:    [[R1:%.*]] = sdiv i8 [[NOTC]], [[USE2B]]
+; CHECK-NEXT:    [[R2:%.*]] = sdiv i8 [[R1]], [[USE2A]]
+; CHECK-NEXT:    ret i8 [[R2]]
+;
+  %use2b = mul i8 %B, 23
+  %nota = xor i8 %A, -1
+  %use2a = mul i8 %nota, 17
+  %c = or i8 %nota, %B
+  %notc = xor i8 %c, -1
+  %r1 = sdiv i8 %notc, %use2b
+  %r2 = sdiv i8 %r1, %use2a
+  ret i8 %r2
+}
+
+; ~(~A | B) --> (A & ~B) - what if we use two of the intermediate results?
+
+define i8 @demorgan_nor_use2ac(i8 %A, i8 %B) {
+; CHECK-LABEL: @demorgan_nor_use2ac(
+; CHECK-NEXT:    [[NOTA:%.*]] = xor i8 %A, -1
+; CHECK-NEXT:    [[USE2A:%.*]] = mul i8 [[NOTA]], 17
+; CHECK-NEXT:    [[C:%.*]] = or i8 [[NOTA]], %B
+; CHECK-NEXT:    [[USE2C:%.*]] = mul i8 [[C]], 23
+; CHECK-NEXT:    [[B_NOT:%.*]] = xor i8 %B, -1
+; CHECK-NEXT:    [[NOTC:%.*]] = and i8 [[B_NOT]], %A
+; CHECK-NEXT:    [[R1:%.*]] = sdiv i8 [[NOTC]], [[USE2C]]
+; CHECK-NEXT:    [[R2:%.*]] = sdiv i8 [[R1]], [[USE2A]]
+; CHECK-NEXT:    ret i8 [[R2]]
+;
+  %nota = xor i8 %A, -1
+  %use2a = mul i8 %nota, 17
+  %c = or i8 %nota, %B
+  %use2c = mul i8 %c, 23
+  %notc = xor i8 %c, -1
+  %r1 = sdiv i8 %notc, %use2c
+  %r2 = sdiv i8 %r1, %use2a
+  ret i8 %r2
+}
+
+; ~(~A | B) --> (A & ~B) - what if we use two of the intermediate results?
+
+define i8 @demorgan_nor_use2bc(i8 %A, i8 %B) {
+; CHECK-LABEL: @demorgan_nor_use2bc(
+; CHECK-NEXT:    [[USE2B:%.*]] = mul i8 %B, 23
+; CHECK-NEXT:    [[NOTA:%.*]] = xor i8 %A, -1
+; CHECK-NEXT:    [[C:%.*]] = or i8 [[NOTA]], %B
+; CHECK-NEXT:    [[USE2C:%.*]] = mul i8 [[C]], 23
+; CHECK-NEXT:    [[B_NOT:%.*]] = xor i8 %B, -1
+; CHECK-NEXT:    [[NOTC:%.*]] = and i8 [[B_NOT]], %A
+; CHECK-NEXT:    [[R1:%.*]] = sdiv i8 [[NOTC]], [[USE2C]]
+; CHECK-NEXT:    [[R2:%.*]] = sdiv i8 [[R1]], [[USE2B]]
+; CHECK-NEXT:    ret i8 [[R2]]
+;
+  %use2b = mul i8 %B, 23
+  %nota = xor i8 %A, -1
+  %c = or i8 %nota, %B
+  %use2c = mul i8 %c, 23
+  %notc = xor i8 %c, -1
+  %r1 = sdiv i8 %notc, %use2c
+  %r2 = sdiv i8 %r1, %use2b
+  ret i8 %r2
+}
+
 ; FIXME: Do not apply DeMorgan's Law to constants. We prefer 'not' ops.
 
 define i32 @demorganize_constant1(i32 %a) {