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Don't attempt to divide INT_MIN by -1; consider such cases to
have overflowed. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96428 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -2112,12 +2112,16 @@ void LSRInstance::GenerateICmpZeroScales(LSRUse &LU, unsigned LUIdx,
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Formula F = Base;
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// Check that the multiplication doesn't overflow.
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if (F.AM.BaseOffs == INT64_MIN && Factor == -1)
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continue;
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F.AM.BaseOffs = (uint64_t)Base.AM.BaseOffs * Factor;
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if ((int64_t)F.AM.BaseOffs / Factor != Base.AM.BaseOffs)
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continue;
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// Check that multiplying with the use offset doesn't overflow.
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int64_t Offset = LU.MinOffset;
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if (Offset == INT64_MIN && Factor == -1)
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continue;
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Offset = (uint64_t)Offset * Factor;
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if ((int64_t)Offset / Factor != LU.MinOffset)
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continue;
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26
test/CodeGen/X86/lsr-overflow.ll
Normal file
26
test/CodeGen/X86/lsr-overflow.ll
Normal file
@ -0,0 +1,26 @@
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; RUN: llc < %s -march=x86-64 | FileCheck %s
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; The comparison uses the pre-inc value, which could lead LSR to
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; try to compute -INT64_MIN.
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; CHECK: movabsq $-9223372036854775808, %rax ## imm = 0x8000000000000000
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; CHECK: cmpq %rax, %rbx
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; CHECK: sete %al
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declare i64 @bar()
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define i1 @foo() nounwind {
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entry:
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br label %for.cond.i
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for.cond.i:
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%indvar = phi i64 [ 0, %entry ], [ %indvar.next, %for.cond.i ]
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%t = call i64 @bar()
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%indvar.next = add i64 %indvar, 1
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%s = icmp ne i64 %indvar.next, %t
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br i1 %s, label %for.cond.i, label %__ABContainsLabel.exit
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__ABContainsLabel.exit:
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%cmp = icmp eq i64 %indvar, 9223372036854775807
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ret i1 %cmp
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}
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