read-only-calls.ll
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; RUN: opt -S -basicaa -licm -licm-n2-threshold=0 -enable-mssa-loop-dependency=false %s | FileCheck %s
; RUN: opt -S -basicaa -licm -licm-n2-threshold=0 -enable-mssa-loop-dependency=true %s | FileCheck %s --check-prefix=ALIAS-N2
; RUN: opt -licm -basicaa -licm-n2-threshold=200 < %s -S | FileCheck %s --check-prefix=ALIAS-N2
; RUN: opt -aa-pipeline=basic-aa -licm-n2-threshold=0 -passes='require<aa>,require<targetir>,require<scalar-evolution>,require<opt-remark-emit>,loop(licm)' < %s -S | FileCheck %s
; RUN: opt -aa-pipeline=basic-aa -licm-n2-threshold=0 -passes='require<aa>,require<targetir>,require<scalar-evolution>,require<opt-remark-emit>,loop-mssa(licm)' < %s -S | FileCheck %s --check-prefix=ALIAS-N2
; RUN: opt -aa-pipeline=basic-aa -licm-n2-threshold=200 -passes='require<aa>,require<targetir>,require<scalar-evolution>,require<opt-remark-emit>,loop(licm)' < %s -S | FileCheck %s --check-prefix=ALIAS-N2
; 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, i32*) 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(i32* %ptr) {
; CHECK-LABEL: @test1(
; CHECK-LABEL: entry:
; CHECK-LABEL: loop:
; CHECK: %val = load i32, i32* %ptr
; ALIAS-N2-LABEL: @test1(
; ALIAS-N2-LABEL: entry:
; ALIAS-N2: %val = load i32, i32* %ptr
; ALIAS-N2-LABEL: loop:
entry:
br label %loop
loop:
%x = phi i32 [ 0, %entry ], [ %x.inc, %loop ]
%val = load i32, i32* %ptr
call void @foo(i64 4, i32* %ptr)
%p2 = getelementptr i32, i32* %ptr, i32 1
store volatile i32 0, i32* %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(i32* %ptr) {
; CHECK-LABEL: @test2(
; CHECK-LABEL: entry:
; CHECK: %val = load i32, i32* %ptr
; CHECK-LABEL: loop:
; ALIAS-N2-LABEL: @test2(
; ALIAS-N2-LABEL: entry:
; ALIAS-N2: %val = load i32, i32* %ptr
; ALIAS-N2-LABEL: loop:
entry:
br label %loop
loop:
%x = phi i32 [ 0, %entry ], [ %x.inc, %loop ]
%val = load i32, i32* %ptr
call void @foo(i64 4, i32* %ptr)
%x.inc = add i32 %x, %val
br label %loop
}
; cannot hoist load since not guaranteed to execute
define void @test3(i32* %ptr) {
; CHECK-LABEL: @test3(
; CHECK-LABEL: entry:
; CHECK-LABEL: loop:
; CHECK: %val = load i32, i32* %ptr
; ALIAS-N2-LABEL: @test3(
; ALIAS-N2-LABEL: entry:
; ALIAS-N2-LABEL: loop:
; ALIAS-N2: %val = load i32, i32* %ptr
entry:
br label %loop
loop:
%x = phi i32 [ 0, %entry ], [ %x.inc, %loop ]
call void @foo(i64 4, i32* %ptr)
%val = load i32, i32* %ptr
%x.inc = add i32 %x, %val
br label %loop
}