68 lines
1.9 KiB
LLVM
68 lines
1.9 KiB
LLVM
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; RUN: opt -aa-pipeline=basic-aa -passes='require<aa>,require<targetir>,require<scalar-evolution>,require<opt-remark-emit>,loop-mssa(licm)' < %s -S | FileCheck %s
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; We should be able to hoist loads in presence of read only calls and stores
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; that do not alias.
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; Since LICM uses the AST mechanism for alias analysis, we will clump
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; together all loads and stores in one set along with the read-only call.
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; This prevents hoisting load that doesn't alias with any other memory
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; operations.
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declare void @foo(i64, ptr) readonly
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; hoist the load out with the n2-threshold
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; since it doesn't alias with the store.
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; default AST mechanism clumps all memory locations in one set because of the
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; readonly call
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define void @test1(ptr %ptr) {
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; CHECK-LABEL: @test1(
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; CHECK-LABEL: entry:
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; CHECK: %val = load i32, ptr %ptr
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; CHECK-LABEL: loop:
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entry:
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br label %loop
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loop:
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%x = phi i32 [ 0, %entry ], [ %x.inc, %loop ]
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%val = load i32, ptr %ptr
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call void @foo(i64 4, ptr %ptr)
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%p2 = getelementptr i32, ptr %ptr, i32 1
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store volatile i32 0, ptr %p2
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%x.inc = add i32 %x, %val
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br label %loop
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}
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; can hoist out load with the default AST and the alias analysis mechanism.
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define void @test2(ptr %ptr) {
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; CHECK-LABEL: @test2(
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; CHECK-LABEL: entry:
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; CHECK: %val = load i32, ptr %ptr
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; CHECK-LABEL: loop:
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entry:
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br label %loop
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loop:
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%x = phi i32 [ 0, %entry ], [ %x.inc, %loop ]
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%val = load i32, ptr %ptr
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call void @foo(i64 4, ptr %ptr)
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%x.inc = add i32 %x, %val
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br label %loop
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}
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; cannot hoist load since not guaranteed to execute
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define void @test3(ptr %ptr) {
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; CHECK-LABEL: @test3(
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; CHECK-LABEL: entry:
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; CHECK-LABEL: loop:
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; CHECK: %val = load i32, ptr %ptr
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entry:
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br label %loop
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loop:
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%x = phi i32 [ 0, %entry ], [ %x.inc, %loop ]
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call void @foo(i64 4, ptr %ptr)
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%val = load i32, ptr %ptr
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%x.inc = add i32 %x, %val
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br label %loop
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}
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