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The included test case is derived from one of the GCC compatibility tests. The problem arises after the selection DAG has been converted to type-legalized form. The combiner first sees a 64-bit load that can be converted into a pre-increment form. The original load feeds into a SRL that isolates the upper 32 bits of the loaded doubleword. This looks like an opportunity for DAGCombiner::ReduceLoadWidth() to replace the 64-bit load with a 32-bit load. However, this transformation is not valid, as the replacement load is not a pre-increment load. The pre-increment load produces an extra result, which feeds a subsequent add instruction. The replacement load only has one result value, and this value is propagated to all uses of the pre- increment load, including the add. Because the add is looking for the second result value as its operand, it ends up attempting to add a constant to a token chain, resulting in a crash. So the patch simply disables this transformation for any load with more than two result values. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172480 91177308-0d34-0410-b5e6-96231b3b80d8
35 lines
1.9 KiB
LLVM
35 lines
1.9 KiB
LLVM
; RUN: llc < %s
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; This used to cause a crash. A standard load is converted to a pre-increment
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; load. Later the pre-increment load is combined with a subsequent SRL to
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; produce a smaller load. This transform invalidly created a standard load
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; and propagated the produced value into uses of both produced values of the
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; pre-increment load. The result was a crash when attempting to process an
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; add with a token-chain operand.
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%struct.Info = type { i32, i32, i8*, i8*, i8*, [32 x i8*], i64, [32 x i64], i64, i64, i64, [32 x i64] }
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%struct.S1847 = type { [12 x i8], [4 x i8], [8 x i8], [4 x i8], [8 x i8], [2 x i8], i8, [4 x i64], i8, [3 x i8], [4 x i8], i8, i16, [4 x %struct.anon.76], i16, i8, i8* }
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%struct.anon.76 = type { i32 }
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@info = common global %struct.Info zeroinitializer, align 8
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@fails = common global i32 0, align 4
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@a1847 = external global [5 x %struct.S1847]
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define void @test1847() nounwind {
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entry:
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%j = alloca i32, align 4
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%0 = load i64* getelementptr inbounds (%struct.Info* @info, i32 0, i32 8), align 8
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%1 = load i32* @fails, align 4
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%bf.load1 = load i96* bitcast (%struct.S1847* getelementptr inbounds ([5 x %struct.S1847]* @a1847, i32 0, i64 2) to i96*), align 8
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%bf.clear2 = and i96 %bf.load1, 302231454903657293676543
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%bf.set3 = or i96 %bf.clear2, -38383394772764476296921088
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store i96 %bf.set3, i96* bitcast (%struct.S1847* getelementptr inbounds ([5 x %struct.S1847]* @a1847, i32 0, i64 2) to i96*), align 8
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%2 = load i32* %j, align 4
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%3 = load i32* %j, align 4
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%inc11 = add nsw i32 %3, 1
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store i32 %inc11, i32* %j, align 4
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%bf.load15 = load i96* bitcast (%struct.S1847* getelementptr inbounds ([5 x %struct.S1847]* @a1847, i32 0, i64 2) to i96*), align 8
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%bf.clear16 = and i96 %bf.load15, -18446744069414584321
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%bf.set17 = or i96 %bf.clear16, 18446743532543672320
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store i96 %bf.set17, i96* bitcast (%struct.S1847* getelementptr inbounds ([5 x %struct.S1847]* @a1847, i32 0, i64 2) to i96*), align 8
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ret void
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}
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