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llvm-project/polly/test/ScopInfo/invariant_load_canonicalize...

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[Polly] Canonicalize arrays according to base-ptr equivalence class Summary: In case two arrays share base pointers in the same invariant load equivalence class, we canonicalize all memory accesses to the first of these arrays (according to their order in the equivalence class). This enables us to optimize kernels such as boost::ublas by ensuring that different references to the C array are interpreted as accesses to the same array. Before this change the runtime alias check for ublas would fail, as it would assume models of the C array with differing (but identically valued) base pointers would reference distinct regions of memory whereas the referenced memory regions were indeed identical. As part of this change we remove most of the MemoryAccess::get*BaseAddr interface. We removed already all references to get*BaseAddr in previous commits to ensure that no code relies on matching base pointers between memory accesses and scop arrays -- except for three remaining uses where we need the original base pointer. We document for these situations that MemoryAccess::getOriginalBaseAddr may return a base pointer that is distinct to the base pointer of the scop array referenced by this memory access. Reviewers: sebpop, Meinersbur, zinob, gareevroman, pollydev, huihuiz, efriedma, jdoerfert Reviewed By: Meinersbur Subscribers: etherzhhb Tags: #polly Differential Revision: https://reviews.llvm.org/D28518 llvm-svn: 302636
2017-05-10 18:59:58 +08:00
; RUN: opt %loadPolly -polly-scops -analyze < %s \
; RUN: -polly-invariant-load-hoisting \
; RUN: | FileCheck %s
; Verify that we canonicalize accesses even tough one of the accesses (even
; the canonical base) has a partial execution context. This is correct as
; the combined execution context still coveres both accesses.
; CHECK: Invariant Accesses: {
; CHECK-NEXT: ReadAccess := [Reduction Type: NONE] [Scalar: 0]
; CHECK-NEXT: { Stmt_body2[i0] -> MemRef_A[0] };
; CHECK-NEXT: Execution Context: { : }
; CHECK-NEXT: }
; CHECK: Stmt_body1
; CHECK-NEXT: Domain :=
; CHECK-NEXT: { Stmt_body1[i0] : 0 <= i0 <= 1022 };
; CHECK-NEXT: Schedule :=
; CHECK-NEXT: { Stmt_body1[i0] -> [i0, 0] };
; CHECK-NEXT: MustWriteAccess := [Reduction Type: NONE] [Scalar: 0]
; CHECK-NEXT: { Stmt_body1[i0] -> MemRef_baseB[0] };
; CHECK-NEXT: Stmt_body2
; CHECK-NEXT: Domain :=
; CHECK-NEXT: { Stmt_body2[i0] : 0 <= i0 <= 510 };
; CHECK-NEXT: Schedule :=
; CHECK-NEXT: { Stmt_body2[i0] -> [i0, 1] };
; CHECK-NEXT: MustWriteAccess := [Reduction Type: NONE] [Scalar: 0]
; CHECK-NEXT: { Stmt_body2[i0] -> MemRef_baseB[0] };
define void @foo(float** %A) {
start:
br label %loop
loop:
%indvar = phi i64 [0, %start], [%indvar.next, %latch]
%indvar.next = add nsw i64 %indvar, 1
%icmp = icmp slt i64 %indvar.next, 1024
br i1 %icmp, label %body1, label %exit
body1:
%baseA = load float*, float** %A
store float 42.0, float* %baseA
%cmp = icmp slt i64 %indvar.next, 512
br i1 %cmp, label %body2, label %latch
body2:
%baseB = load float*, float** %A
store float 42.0, float* %baseB
br label %latch
latch:
br label %loop
exit:
ret void
}