[PATCH] D115755: [InstSimplify] Fold logic And to Zero

[Mehrnoosh Heidarpour via Phabricator via llvm-commits]

MehrHeidar updated this revision to Diff 394641.
MehrHeidar added a comment.

Address review comments.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D115755/new/

https://reviews.llvm.org/D115755

Files:
  llvm/lib/Analysis/InstructionSimplify.cpp
  llvm/test/Transforms/InstSimplify/and.ll


Index: llvm/test/Transforms/InstSimplify/and.ll
===================================================================
--- llvm/test/Transforms/InstSimplify/and.ll
+++ llvm/test/Transforms/InstSimplify/and.ll
@@ -132,15 +132,11 @@
   ret i8 %and
 }
 
-; ((A | B) ^ A ) & ((A | B) ^ B)
+; ((A | B) ^ A ) & ((A | B) ^ B) --> 0
 
 define i8 @or_xor(i8 %x, i8 %y) {
 ; CHECK-LABEL: @or_xor(
-; CHECK-NEXT:    [[OR:%.*]] = or i8 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[XOR1:%.*]] = xor i8 [[OR]], [[X]]
-; CHECK-NEXT:    [[XOR2:%.*]] = xor i8 [[OR]], [[Y]]
-; CHECK-NEXT:    [[AND:%.*]] = and i8 [[XOR1]], [[XOR2]]
-; CHECK-NEXT:    ret i8 [[AND]]
+; CHECK-NEXT:    ret i8 0
 ;
   %or = or i8 %x, %y
   %xor1 = xor i8 %or, %x
@@ -149,15 +145,11 @@
   ret i8 %and
 }
 
-; ((A | B) ^ B ) & ((A | B) ^ A)
+; ((A | B) ^ B ) & ((A | B) ^ A) --> 0
 
 define i8 @or_xor_commute1(i8 %x, i8 %y) {
 ; CHECK-LABEL: @or_xor_commute1(
-; CHECK-NEXT:    [[OR:%.*]] = or i8 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[XOR1:%.*]] = xor i8 [[OR]], [[X]]
-; CHECK-NEXT:    [[XOR2:%.*]] = xor i8 [[OR]], [[Y]]
-; CHECK-NEXT:    [[AND:%.*]] = and i8 [[XOR2]], [[XOR1]]
-; CHECK-NEXT:    ret i8 [[AND]]
+; CHECK-NEXT:    ret i8 0
 ;
   %or = or i8 %x, %y
   %xor1 = xor i8 %or, %x
@@ -166,15 +158,11 @@
   ret i8 %and
 }
 
-; (A ^ (A | B) ) & (B ^ (A | B))
+; (A ^ (A | B) ) & (B ^ (A | B)) --> 0
 
 define i71 @or_xor_commute2(i71 %x, i71 %y) {
 ; CHECK-LABEL: @or_xor_commute2(
-; CHECK-NEXT:    [[OR:%.*]] = or i71 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[XOR1:%.*]] = xor i71 [[X]], [[OR]]
-; CHECK-NEXT:    [[XOR2:%.*]] = xor i71 [[Y]], [[OR]]
-; CHECK-NEXT:    [[AND:%.*]] = and i71 [[XOR1]], [[XOR2]]
-; CHECK-NEXT:    ret i71 [[AND]]
+; CHECK-NEXT:    ret i71 0
 ;
   %or = or i71 %x, %y
   %xor1 = xor i71 %x, %or
@@ -183,15 +171,11 @@
   ret i71 %and
 }
 
-; (B ^ (A | B) ) & (A ^ (A | B))
+; (B ^ (A | B) ) & (A ^ (A | B)) --> 0
 
 define <2 x i64> @or_xor_commute3(<2 x i64> %x, <2 x i64> %y) {
 ; CHECK-LABEL: @or_xor_commute3(
-; CHECK-NEXT:    [[OR:%.*]] = or <2 x i64> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[XOR1:%.*]] = xor <2 x i64> [[Y]], [[OR]]
-; CHECK-NEXT:    [[XOR2:%.*]] = xor <2 x i64> [[X]], [[OR]]
-; CHECK-NEXT:    [[AND:%.*]] = and <2 x i64> [[XOR1]], [[XOR2]]
-; CHECK-NEXT:    ret <2 x i64> [[AND]]
+; CHECK-NEXT:    ret <2 x i64> zeroinitializer
 ;
   %or = or <2 x i64> %x, %y
   %xor1 = xor <2 x i64> %y, %or
Index: llvm/lib/Analysis/InstructionSimplify.cpp
===================================================================
--- llvm/lib/Analysis/InstructionSimplify.cpp
+++ llvm/lib/Analysis/InstructionSimplify.cpp
@@ -2173,6 +2173,13 @@
     }
   }
 
+  // ((X | Y) ^ X ) & ((X | Y) ^ Y) --> 0
+  if (match(Op0, m_c_Xor(m_c_Or(m_Value(X), m_Value(Y)),
+                         m_CombineOr(m_Deferred(X), m_Deferred(Y)))) &&
+      match(Op1, m_c_Xor(m_c_Or(m_Specific(X), m_Specific(Y)),
+                         m_CombineOr(m_Specific(X), m_Specific(Y)))))
+    return Constant::getNullValue(Op0->getType());
+
   return nullptr;
 }
 


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