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[flang] Improve alias analysis to be precise for box and box.base_addr (#80335)

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After PR#68727 the source for both the fir.box_addr and a box became the
same. Thus the detection that only one of the sources was direct and the
special logic around it was being skipped. As a result, the test
included would show a "MayAlias" result instead of a "NoAlias" result.
This commit is contained in:
Razvan Lupusoru 2024-02-05 07:45:46 -08:00 committed by GitHub
parent 0881d0f009
commit 702664e787
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2 changed files with 41 additions and 1 deletions
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2
flang/lib/Optimizer/Analysis/AliasAnalysis.cpp
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@ -106,7 +106,7 @@ AliasResult AliasAnalysis::alias(Value lhs, Value rhs) {
// Though nothing is known about them, they would only alias with targets or
// pointers
bool directSourceToNonTargetOrPointer = false;
if (lhsSrc.u != rhsSrc.u) {
if (lhsSrc.u != rhsSrc.u || lhsSrc.kind != rhsSrc.kind) {
if ((lhsSrc.kind == SourceKind::Direct && !rhsSrc.isTargetOrPointer()) ||
(rhsSrc.kind == SourceKind::Direct && !lhsSrc.isTargetOrPointer()))
directSourceToNonTargetOrPointer = true;

40
flang/test/Analysis/AliasAnalysis/alias-analysis-8.fir Normal file
View File

@ -0,0 +1,40 @@
// RUN: fir-opt %s -pass-pipeline='builtin.module(func.func(test-fir-alias-analysis))' 2>&1 | FileCheck %s
// Exercise that a box reference does not alias with the address loaded from the box
// module mm
// real, allocatable :: arr(:)
// contains
// subroutine sub
// arr(1) = ubound(arr, 1)
// end subroutine
// end module
// CHECK: box#0 <-> boxaddr#0: NoAlias
fir.global @_QMmmEarr : !fir.box<!fir.heap<!fir.array<?xf32>>> {
%c0 = arith.constant 0 : index
%0 = fir.zero_bits !fir.heap<!fir.array<?xf32>>
%1 = fir.shape %c0 : (index) -> !fir.shape<1>
%2 = fir.embox %0(%1) : (!fir.heap<!fir.array<?xf32>>, !fir.shape<1>) -> !fir.box<!fir.heap<!fir.array<?xf32>>>
fir.has_value %2 : !fir.box<!fir.heap<!fir.array<?xf32>>>
}
func.func @_QMmmPsub() {
%c1 = arith.constant 1 : index
%c1_i64 = arith.constant 1 : i64
%c0 = arith.constant 0 : index
%0 = fir.address_of(@_QMmmEarr) : !fir.ref<!fir.box<!fir.heap<!fir.array<?xf32>>>>
%1 = fir.declare %0 {fortran_attrs = #fir.var_attrs<allocatable>, uniq_name = "_QMmmEarr", test.ptr = "box"} : (!fir.ref<!fir.box<!fir.heap<!fir.array<?xf32>>>>) -> !fir.ref<!fir.box<!fir.heap<!fir.array<?xf32>>>>
%2 = fir.load %1 : !fir.ref<!fir.box<!fir.heap<!fir.array<?xf32>>>>
%3:3 = fir.box_dims %2, %c0 : (!fir.box<!fir.heap<!fir.array<?xf32>>>, index) -> (index, index, index)
%4 = fir.convert %3#1 : (index) -> i64
%5 = fir.convert %3#0 : (index) -> i64
%6 = arith.addi %4, %5 : i64
%7 = arith.subi %6, %c1_i64 : i64
%8 = fir.convert %7 : (i64) -> i32
%9 = fir.convert %8 : (i32) -> f32
%10 = fir.box_addr %2 {test.ptr = "boxaddr"} : (!fir.box<!fir.heap<!fir.array<?xf32>>>) -> !fir.heap<!fir.array<?xf32>>
%11 = fir.shape_shift %3#0, %3#1 : (index, index) -> !fir.shapeshift<1>
%12 = fir.array_coor %10(%11) %c1 : (!fir.heap<!fir.array<?xf32>>, !fir.shapeshift<1>, index) -> !fir.ref<f32>
fir.store %9 to %12 : !fir.ref<f32>
return
}