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InstructionSimplify should be able to simplify A+B==B+A to 'true'

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but wasn't due to the same logic bug that caused PR14361.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168186 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Duncan Sands 2012-11-16 19:41:26 +00:00
parent 48f63be368
commit aceb03eb58
2 changed files with 23 additions and 2 deletions
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16
lib/Analysis/InstructionSimplify.cpp
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@ -2065,8 +2065,20 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
if (A && C && (A == C || A == D || B == C || B == D) &&
NoLHSWrapProblem && NoRHSWrapProblem) {
// Determine Y and Z in the form icmp (X+Y), (X+Z).
Value *Y = (A == C || A == D) ? B : A;
Value *Z = (C == A || C == B) ? D : C;
Value *Y, *Z;
if (A == C) {
Y = B;
Z = D;
} else if (A == D) {
Y = B;
Z = C;
} else if (B == C) {
Y = A;
Z = D;
} else if (B == D) {
Y = A;
Z = C;
}
if (Value *V = SimplifyICmpInst(Pred, Y, Z, Q, MaxRecurse-1))
return V;
}

9
test/Transforms/InstSimplify/compare.ll
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@ -266,6 +266,15 @@ define i1 @add5(i32 %x, i32 %y) {
; CHECK: ret i1 true
}
define i1 @add6(i64 %A, i64 %B) {
; CHECK: @add6
%s1 = add i64 %A, %B
%s2 = add i64 %B, %A
%cmp = icmp eq i64 %s1, %s2
ret i1 %cmp
; CHECK: ret i1 true
}
define i1 @addpowtwo(i32 %x, i32 %y) {
; CHECK: @addpowtwo
%l = lshr i32 %x, 1