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[flang] Support fir.pack_array in FIR alias analysis. (#131946)
`fir.pack_array` is just a pass-through op for the process of finding the source in FIR alias analysis (as defined in #127147).
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flang/lib/Optimizer/Analysis/AliasAnalysis.cpp

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@@ -542,6 +542,14 @@ AliasAnalysis::Source AliasAnalysis::getSource(mlir::Value v,
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v = op->getOperand(0);
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defOp = v.getDefiningOp();
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})
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.Case<fir::PackArrayOp>([&](auto op) {
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// The packed array is not distinguishable from the original
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// array, so skip PackArrayOp and track further through
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// the array operand.
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v = op.getArray();
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defOp = v.getDefiningOp();
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approximateSource = true;
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})
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.Case<fir::BoxAddrOp>([&](auto op) {
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v = op->getOperand(0);
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defOp = v.getDefiningOp();
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// Test alias analysis queries for dummy arguments wired
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// through fir.pack_array.
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// fir.pack_array is a pass-through operation for FIR alias analysis.
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// RUN: fir-opt %s --test-fir-alias-analysis -split-input-file --mlir-disable-threading 2>&1 | FileCheck %s
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// The two pointers referencing two different maybe repacked
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// versions of the original dummy arguments do not alias:
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// CHECK-DAG: test1_y_repack(1)#0 <-> test1_x_repack(1)#0: NoAlias
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// CHECK-DAG: test1_x_orig(1)#0 <-> test1_y_orig(1)#0: NoAlias
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// Repacked dummy does not alias with another original dummy:
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// CHECK-DAG: test1_y_repack(1)#0 <-> test1_x_orig(1)#0: NoAlias
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// CHECK-DAG: test1_x_repack(1)#0 <-> test1_y_orig(1)#0: NoAlias
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// Repacked dummy may alias with its original:
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// CHECK-DAG: test1_x_repack(1)#0 <-> test1_x_orig(1)#0: MayAlias
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// CHECK-DAG: test1_y_repack(1)#0 <-> test1_y_orig(1)#0: MayAlias
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// Ideally, these should report MustAlias, but MayAlias
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// may work as well:
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// CHECK-DAG: test1_y_repack(1)#0 <-> test1_y_repack2(1)#0: MayAlias
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// CHECK-DAG: test1_x_repack(1)#0 <-> test1_x_repack2(1)#0: MayAlias
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func.func @_QFtest1(%arg0: !fir.box<!fir.array<?xf32>> {fir.bindc_name = "x"}, %arg1: !fir.box<!fir.array<?xf32>> {fir.bindc_name = "y"}) {
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%c1 = arith.constant 1 : index
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%0 = fir.dummy_scope : !fir.dscope
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%1 = fir.pack_array %arg0 heap whole : (!fir.box<!fir.array<?xf32>>) -> !fir.box<!fir.array<?xf32>>
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%2:2 = hlfir.declare %1 dummy_scope %0 {uniq_name = "_QFtest1Ex"} : (!fir.box<!fir.array<?xf32>>, !fir.dscope) -> (!fir.box<!fir.array<?xf32>>, !fir.box<!fir.array<?xf32>>)
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%3 = fir.pack_array %arg1 heap whole : (!fir.box<!fir.array<?xf32>>) -> !fir.box<!fir.array<?xf32>>
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%4:2 = hlfir.declare %3 dummy_scope %0 {uniq_name = "_QFtest1Ey"} : (!fir.box<!fir.array<?xf32>>, !fir.dscope) -> (!fir.box<!fir.array<?xf32>>, !fir.box<!fir.array<?xf32>>)
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%5 = fir.box_addr %4#0 {test.ptr = "test1_y_repack(1)"} : (!fir.box<!fir.array<?xf32>>) -> !fir.ref<f32>
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%52 = fir.box_addr %4#0 {test.ptr = "test1_y_repack2(1)"} : (!fir.box<!fir.array<?xf32>>) -> !fir.ref<f32>
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%6 = fir.load %5 : !fir.ref<f32>
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%7 = fir.box_addr %2#0 {test.ptr = "test1_x_repack(1)"} : (!fir.box<!fir.array<?xf32>>) -> !fir.ref<f32>
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%72 = fir.box_addr %2#0 {test.ptr = "test1_x_repack2(1)"} : (!fir.box<!fir.array<?xf32>>) -> !fir.ref<f32>
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hlfir.assign %6 to %7 : f32, !fir.ref<f32>
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fir.unpack_array %3 to %arg1 heap : !fir.box<!fir.array<?xf32>>
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fir.unpack_array %1 to %arg0 heap : !fir.box<!fir.array<?xf32>>
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%8 = fir.box_addr %arg0 {test.ptr = "test1_x_orig(1)"} : (!fir.box<!fir.array<?xf32>>) -> !fir.ref<f32>
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%9 = fir.box_addr %arg1 {test.ptr = "test1_y_orig(1)"} : (!fir.box<!fir.array<?xf32>>) -> !fir.ref<f32>
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return
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}

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