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94c82b281d
This patch makes MemorySSA recognize atomic/volatile loads, and makes MSSA treat said loads specially. This allows us to be a bit more aggressive in some cases. Administrative note: Revision was LGTM'ed by reames in person. Additionally, this doesn't include the `invariant.load` recognition in the differential revision, because I feel it's better to commit that separately. Will commit soon. Differential Revision: https://reviews.llvm.org/D16875 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277637 91177308-0d34-0410-b5e6-96231b3b80d8
42 lines
1.2 KiB
LLVM
42 lines
1.2 KiB
LLVM
; RUN: opt -basicaa -print-memoryssa -verify-memoryssa -analyze < %s 2>&1 | FileCheck %s
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;
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; Things that BasicAA can prove points to constant memory should be
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; liveOnEntry, as well.
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declare void @clobberAllTheThings()
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@str = private unnamed_addr constant [2 x i8] c"hi"
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define i8 @foo() {
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; CHECK: 1 = MemoryDef(liveOnEntry)
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; CHECK-NEXT: call void @clobberAllTheThings()
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call void @clobberAllTheThings()
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%1 = getelementptr [2 x i8], [2 x i8]* @str, i64 0, i64 0
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; CHECK: MemoryUse(liveOnEntry)
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; CHECK-NEXT: %2 = load i8
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%2 = load i8, i8* %1, align 1
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%3 = getelementptr [2 x i8], [2 x i8]* @str, i64 0, i64 1
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; CHECK: MemoryUse(liveOnEntry)
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; CHECK-NEXT: %4 = load i8
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%4 = load i8, i8* %3, align 1
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%5 = add i8 %2, %4
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ret i8 %5
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}
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define i8 @select(i1 %b) {
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%1 = alloca i8, align 1
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; CHECK: 1 = MemoryDef(liveOnEntry)
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; CHECK-NEXT: store i8 0
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store i8 0, i8* %1, align 1
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; CHECK: 2 = MemoryDef(1)
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; CHECK-NEXT: call void @clobberAllTheThings()
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call void @clobberAllTheThings()
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%2 = getelementptr [2 x i8], [2 x i8]* @str, i64 0, i64 0
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%3 = select i1 %b, i8* %2, i8* %1
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; CHECK: MemoryUse(2)
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; CHECK-NEXT: %4 = load i8
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%4 = load i8, i8* %3, align 1
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ret i8 %4
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}
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