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83
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1 ; RUN: opt -S < %s -instcombine | FileCheck %s
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2
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3 target datalayout = "e-p1:16:16-p2:32:32-p3:64:64"
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4
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5 @G1 = global i32 42, align 1
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6 @G2 = global i32 42
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7 @G3 = global [4 x i8] zeroinitializer, align 1
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8
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9 @A1 = alias bitcast (i8* getelementptr inbounds ([4 x i8]* @G3, i32 0, i32 2) to i32*)
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10 @A2 = alias inttoptr (i64 and (i64 ptrtoint (i8* getelementptr inbounds ([4 x i8]* @G3, i32 0, i32 3) to i64), i64 -4) to i32*)
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11
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12 define i64 @f1() {
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13 ; This cannot be constant folded because G1 is underaligned.
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14 ; CHECK-LABEL: @f1(
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15 ; CHECK: ret i64 and
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16 ret i64 and (i64 ptrtoint (i32* @G1 to i64), i64 1)
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17 }
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18
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19 define i64 @f2() {
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20 ; The preferred alignment for G2 allows this one to foled to zero.
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21 ; CHECK-LABEL: @f2(
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22 ; CHECK: ret i64 0
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23 ret i64 and (i64 ptrtoint (i32* @G2 to i64), i64 1)
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24 }
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25
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26 define i64 @g1() {
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27 ; This cannot be constant folded because A1 aliases G3 which is underalaigned.
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28 ; CHECK-LABEL: @g1(
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29 ; CHECK: ret i64 and
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30 ret i64 and (i64 ptrtoint (i32* @A1 to i64), i64 1)
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31 }
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32
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33 define i64 @g2() {
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34 ; While A2 also aliases G3 which is underaligned, the math of A2 forces a
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35 ; certain alignment allowing this to fold to zero.
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36 ; CHECK-LABEL: @g2(
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37 ; CHECK: ret i64 0
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38 ret i64 and (i64 ptrtoint (i32* @A2 to i64), i64 1)
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39 }
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40
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