[InstSimplify] X && !(X || Y) --> false

https://alive2.llvm.org/ce/z/7J8Exr

This is a commuted variant that was not included in:
D138853 / f2973327496fc966c4e89597

diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index c83eb96..e2154ca 100644 (file)
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4598,6 +4598,9 @@ static Value *simplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
       // !(X || Y) && X --> false (commuted 2 ways)
       if (match(Cond, m_Not(m_c_LogicalOr(m_Specific(TrueVal), m_Value()))))
         return ConstantInt::getFalse(Cond->getType());
+      // X && !(X || Y) --> false (commuted 2 ways)
+      if (match(TrueVal, m_Not(m_c_LogicalOr(m_Specific(Cond), m_Value()))))
+        return ConstantInt::getFalse(Cond->getType());
 
       // (X || Y) && Y --> Y (commuted 2 ways)
       if (match(Cond, m_c_LogicalOr(m_Specific(TrueVal), m_Value())))

diff --git a/llvm/test/Transforms/InstSimplify/select-logical.ll b/llvm/test/Transforms/InstSimplify/select-logical.ll
index 0fa9c68..e2b124c 100644 (file)
--- a/llvm/test/Transforms/InstSimplify/select-logical.ll
+++ b/llvm/test/Transforms/InstSimplify/select-logical.ll
@@ -200,10 +200,7 @@ define i1 @logical_or_not_and_commute_or(i1 %x, i1 %y) {
 
 define i1 @logical_or_not_commute_and(i1 %x, i1 %y) {
 ; CHECK-LABEL: @logical_or_not_commute_and(
-; CHECK-NEXT:    [[L_AND:%.*]] = select i1 [[X:%.*]], i1 true, i1 [[Y:%.*]]
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[L_AND]], true
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[X]], i1 [[NOT]], i1 false
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %l.and = select i1 %x, i1 true, i1 %y
   %not = xor i1 %l.and, true
@@ -215,10 +212,7 @@ define i1 @logical_or_not_commute_and(i1 %x, i1 %y) {
 
 define i1 @logical_or_not_commute_and_commute_or(i1 %x, i1 %y) {
 ; CHECK-LABEL: @logical_or_not_commute_and_commute_or(
-; CHECK-NEXT:    [[L_AND:%.*]] = select i1 [[X:%.*]], i1 true, i1 [[Y:%.*]]
-; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[L_AND]], true
-; CHECK-NEXT:    [[R:%.*]] = select i1 [[Y]], i1 [[NOT]], i1 false
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %l.and = select i1 %x, i1 true, i1 %y
   %not = xor i1 %l.and, true