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Fix PR14361: wrong simplification of A+B==B+A. You may think that the old logic
replaced by this patch is equivalent to the new logic, but you'd be wrong, and that's exactly where the bug was. There's a similar bug in instsimplify which manifests itself as instsimplify failing to simplify this, rather than doing it wrong, see next commit. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168181 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -2356,8 +2356,20 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
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// Try not to increase register pressure.
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BO0->hasOneUse() && BO1->hasOneUse()) {
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// Determine Y and Z in the form icmp (X+Y), (X+Z).
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Value *Y = (A == C || A == D) ? B : A;
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Value *Z = (C == A || C == B) ? D : C;
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Value *Y, *Z;
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if (A == C) {
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Y = B;
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Z = D;
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} else if (A == D) {
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Y = B;
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Z = C;
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} else if (B == C) {
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Y = A;
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Z = D;
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} else if (B == D) {
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Y = A;
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Z = C;
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}
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return new ICmpInst(Pred, Y, Z);
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}
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@ -659,3 +659,21 @@ define i1 @test64(i8 %a, i32 %b) nounwind {
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; CHECK-NEXT: %c = icmp eq i8 %1, %a
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; CHECK-NEXT: ret i1 %c
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}
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define i1 @test65(i64 %A, i64 %B) {
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%s1 = add i64 %A, %B
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%s2 = add i64 %A, %B
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%cmp = icmp eq i64 %s1, %s2
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; CHECK: @test65
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; CHECK-NEXT: ret i1 true
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ret i1 %cmp
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}
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define i1 @test66(i64 %A, i64 %B) {
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%s1 = add i64 %A, %B
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%s2 = add i64 %B, %A
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%cmp = icmp eq i64 %s1, %s2
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; CHECK: @test66
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; CHECK-NEXT: ret i1 true
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ret i1 %cmp
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}
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