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Teach InstructionSimplify to fold (A & B) & A -> A & B and (A | B) | A -> A | B.

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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
This commit is contained in:
Benjamin Kramer 2010-09-10 22:39:55 +00:00
parent e2d50046fd
commit 6844c8ea5a
3 changed files with 55 additions and 0 deletions
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20
lib/Analysis/InstructionSimplify.cpp
View File

@ -106,6 +106,16 @@ Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD) {
(A == Op0 || B == Op0)) (A == Op0 || B == Op0))
return 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; return 0;
} }
@ -165,6 +175,16 @@ Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD) {
(A == Op0 || B == Op0)) (A == Op0 || B == Op0))
return 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; return 0;
} }

18
test/Transforms/InstCombine/and2.ll
View File

@ -8,3 +8,21 @@ define i1 @test1(double %X, double %Y) {
ret i1 %bothcond ret i1 %bothcond
; CHECK: fcmp ord double %Y, %X ; 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
}

17
test/Transforms/InstCombine/or.ll
View File

@ -350,3 +350,20 @@ define <4 x i32> @test32(<4 x i1> %and.i1352, <4 x i32> %vecinit6.i176, <4 x i32
; CHECK: or <4 x i32> %and.i, %and.i129 ; 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
}