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