Teach InstructionSimplify to fold (A & B) & A -> A & B and (A | B) | A -> A | B.
Reassociate does this but it doesn't catch all cases (e.g. if the operands are i1).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113651 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp
index 24cd343..b49b4d0 100644
--- a/lib/Analysis/InstructionSimplify.cpp
+++ b/lib/Analysis/InstructionSimplify.cpp
@@ -106,6 +106,16 @@
(A == Op0 || B == Op0))
return Op0;
+ // (A & B) & A -> A & B
+ if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
+ (A == Op1 || B == Op1))
+ return Op0;
+
+ // A & (A & B) -> A & B
+ if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
+ (A == Op0 || B == Op0))
+ return Op1;
+
return 0;
}
@@ -165,6 +175,16 @@
(A == Op0 || B == Op0))
return Op0;
+ // (A | B) | A -> A | B
+ if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
+ (A == Op1 || B == Op1))
+ return Op0;
+
+ // A | (A | B) -> A | B
+ if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
+ (A == Op0 || B == Op0))
+ return Op1;
+
return 0;
}
diff --git a/test/Transforms/InstCombine/and2.ll b/test/Transforms/InstCombine/and2.ll
index a5a6574..d898ea3 100644
--- a/test/Transforms/InstCombine/and2.ll
+++ b/test/Transforms/InstCombine/and2.ll
@@ -8,3 +8,21 @@
ret i1 %bothcond
; CHECK: fcmp ord double %Y, %X
}
+
+define i1 @test2(i1 %X, i1 %Y) {
+ %a = and i1 %X, %Y
+ %b = and i1 %a, %X
+ ret i1 %b
+; CHECK: @test2
+; CHECK-NEXT: and i1 %X, %Y
+; CHECK-NEXT: ret
+}
+
+define i32 @test3(i32 %X, i32 %Y) {
+ %a = and i32 %X, %Y
+ %b = and i32 %Y, %a
+ ret i32 %b
+; CHECK: @test3
+; CHECK-NEXT: and i32 %X, %Y
+; CHECK-NEXT: ret
+}
diff --git a/test/Transforms/InstCombine/or.ll b/test/Transforms/InstCombine/or.ll
index c3526b7..eb887ec 100644
--- a/test/Transforms/InstCombine/or.ll
+++ b/test/Transforms/InstCombine/or.ll
@@ -350,3 +350,20 @@
; CHECK: or <4 x i32> %and.i, %and.i129
}
+define i1 @test33(i1 %X, i1 %Y) {
+ %a = or i1 %X, %Y
+ %b = or i1 %a, %X
+ ret i1 %b
+; CHECK: @test33
+; CHECK-NEXT: or i1 %X, %Y
+; CHECK-NEXT: ret
+}
+
+define i32 @test34(i32 %X, i32 %Y) {
+ %a = or i32 %X, %Y
+ %b = or i32 %Y, %a
+ ret i32 %b
+; CHECK: @test34
+; CHECK-NEXT: or i32 %X, %Y
+; CHECK-NEXT: ret
+}