2015-10-10 01:41:29 +08:00
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; RUN: not llvm-as < %s -o /dev/null 2>&1 | FileCheck %s
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declare i8* @foo()
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define void @f1() {
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entry:
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call i8* @foo(), !align !{i64 2}
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ret void
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}
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; CHECK: align applies only to load instructions
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; CHECK-NEXT: call i8* @foo()
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define i8 @f2(i8* %x) {
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entry:
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%y = load i8, i8* %x, !align !{i64 2}
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ret i8 %y
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}
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; CHECK: align applies only to pointer types
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; CHECK-NEXT: load i8, i8* %x
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define i8* @f3(i8** %x) {
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entry:
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%y = load i8*, i8** %x, !align !{}
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ret i8* %y
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}
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; CHECK: align takes one operand
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; CHECK-NEXT: load i8*, i8** %x
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define i8* @f4(i8** %x) {
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entry:
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%y = load i8*, i8** %x, !align !{!"str"}
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ret i8* %y
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}
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; CHECK: align metadata value must be an i64!
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; CHECK-NEXT: load i8*, i8** %x
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define i8* @f5(i8** %x) {
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entry:
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%y = load i8*, i8** %x, !align !{i32 2}
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ret i8* %y
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}
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; CHECK: align metadata value must be an i64!
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; CHECK-NEXT: load i8*, i8** %x
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define i8* @f6(i8** %x) {
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entry:
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%y = load i8*, i8** %x, !align !{i64 3}
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ret i8* %y
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}
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; CHECK: align metadata value must be a power of 2!
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; CHECK-NEXT: load i8*, i8** %x
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define i8* @f7(i8** %x) {
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entry:
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2021-09-25 06:54:17 +08:00
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%y = load i8*, i8** %x, !align !{i64 8589934592}
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2015-10-10 01:41:29 +08:00
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ret i8* %y
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}
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; CHECK: alignment is larger that implementation defined limit
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The maximal representable alignment in LLVM IR is 1GiB, not 512MiB
In LLVM IR, `AlignmentBitfieldElementT` is 5-bit wide
But that means that the maximal alignment exponent is `(1<<5)-2`,
which is `30`, not `29`. And indeed, alignment of `1073741824`
roundtrips IR serialization-deserialization.
While this doesn't seem all that important, this doubles
the maximal supported alignment from 512MiB to 1GiB,
and there's actually one noticeable use-case for that;
On X86, the huge pages can have sizes of 2MiB and 1GiB (!).
So while this doesn't add support for truly huge alignments,
which i think we can easily-ish do if wanted, i think this adds
zero-cost support for a not-trivially-dismissable case.
I don't believe we need any upgrade infrastructure,
and since we don't explicitly record the IR version,
we don't need to bump one either.
As @craig.topper speculates in D108661#2963519,
this might be an artificial limit imposed by the original implementation
of the `getAlignment()` functions.
Differential Revision: https://reviews.llvm.org/D108661
2021-08-26 16:51:28 +08:00
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; CHECK-NEXT: load i8*, i8** %x
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