[flang-commits] [flang] [flang] fix a dangling else in allOtherUsesAreSafeForAssociate (PR #189748)

[via flang-commits]

https://github.com/yebinchon updated https://github.com/llvm/llvm-project/pull/189748

>From 752e82056992a8e0a4ed994c118fdb6bb015cbb4 Mon Sep 17 00:00:00 2001
From: Yebin Chon <ychon at nvidia.com>
Date: Tue, 31 Mar 2026 13:50:26 -0700
Subject: [PATCH 1/3] fix a dangling else that caused isBeforeInBlock to be
 called when instructions were in different blocks

---
 flang/lib/Optimizer/HLFIR/Transforms/BufferizeHLFIR.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/flang/lib/Optimizer/HLFIR/Transforms/BufferizeHLFIR.cpp b/flang/lib/Optimizer/HLFIR/Transforms/BufferizeHLFIR.cpp
index 53ff13f5a9d28..35cbdd59cf5d8 100644
--- a/flang/lib/Optimizer/HLFIR/Transforms/BufferizeHLFIR.cpp
+++ b/flang/lib/Optimizer/HLFIR/Transforms/BufferizeHLFIR.cpp
@@ -382,11 +382,12 @@ static bool allOtherUsesAreSafeForAssociate(mlir::Value value,
         if (!endAssociate)
           continue;
         // If useOp dominates the endAssociate, then it is definitely safe.
-        if (useOp->getBlock() != endAssociate->getBlock())
+        if (useOp->getBlock() != endAssociate->getBlock()) {
           if (mlir::DominanceInfo{}.dominates(useOp, endAssociate))
             continue;
-        if (useOp->isBeforeInBlock(endAssociate))
+        } else if (useOp->isBeforeInBlock(endAssociate)) {
           continue;
+        }
       }
       return false;
     }

>From 52b708ac016139ba0f43d070aa6d537a051e8f86 Mon Sep 17 00:00:00 2001
From: Yebin Chon <ychon at nvidia.com>
Date: Tue, 31 Mar 2026 14:26:59 -0700
Subject: [PATCH 2/3] added test

---
 flang/test/HLFIR/bufferize-associate-block-ordering.fir | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 create mode 100644 flang/test/HLFIR/bufferize-associate-block-ordering.fir

diff --git a/flang/test/HLFIR/bufferize-associate-block-ordering.fir b/flang/test/HLFIR/bufferize-associate-block-ordering.fir
new file mode 100644
index 0000000000000..e69de29bb2d1d

>From aaec9469a6bbecf75f317b69fa55249196884f22 Mon Sep 17 00:00:00 2001
From: Yebin Chon <ychon at nvidia.com>
Date: Tue, 31 Mar 2026 14:28:37 -0700
Subject: [PATCH 3/3] added test body

---
 .../bufferize-associate-block-ordering.fir    | 41 +++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/flang/test/HLFIR/bufferize-associate-block-ordering.fir b/flang/test/HLFIR/bufferize-associate-block-ordering.fir
index e69de29bb2d1d..57c8ec5102cc8 100644
--- a/flang/test/HLFIR/bufferize-associate-block-ordering.fir
+++ b/flang/test/HLFIR/bufferize-associate-block-ordering.fir
@@ -0,0 +1,41 @@
+// RUN: fir-opt --bufferize-hlfir %s | FileCheck %s
+
+func.func @shape_of_non_dominating_block(%cond: i1, %n: index) {
+  %shape = fir.shape %n : (index) -> !fir.shape<1>
+  %expr = hlfir.elemental %shape : (!fir.shape<1>) -> !hlfir.expr<?xi32> {
+  ^bb0(%i: index):
+    %c0 = arith.constant 0 : i32
+    hlfir.yield_element %c0 : i32
+  }
+  %assoc:3 = hlfir.associate %expr(%shape) {uniq_name = "test"} : (!hlfir.expr<?xi32>, !fir.shape<1>) -> (!fir.box<!fir.array<?xi32>>, !fir.ref<!fir.array<?xi32>>, i1)
+  cf.cond_br %cond, ^bb1, ^bb2
+^bb1:
+  %s = hlfir.shape_of %expr : (!hlfir.expr<?xi32>) -> !fir.shape<1>
+  cf.br ^bb3
+^bb2:
+  cf.br ^bb3
+^bb3:
+  hlfir.end_associate %assoc#1, %assoc#2 : !fir.ref<!fir.array<?xi32>>, i1
+  hlfir.destroy %expr : !hlfir.expr<?xi32>
+  return
+}
+
+// The shape_of in ^bb1 does not dominate the end_associate in ^bb3
+// (^bb3 is reachable from ^bb2 as well), so allOtherUsesAreSafeForAssociate
+// returns false and the associate takes the copy path.
+// CHECK-LABEL: func.func @shape_of_non_dominating_block(
+// CHECK-SAME:    %[[COND:.*]]: i1, %[[N:.*]]: index)
+// CHECK:       %[[SHAPE:.*]] = fir.shape %[[N]]
+// CHECK:       %[[ELEM_BUF:.*]] = fir.allocmem !fir.array<?xi32>, %[[N]] {{.*}}".tmp.array"
+// CHECK:       fir.do_loop
+// CHECK:       %[[COPY_BUF:.*]] = fir.allocmem !fir.array<?xi32>, %[[N]] {{.*}}".tmp"
+// CHECK:       hlfir.assign %{{.*}} to %{{.*}} temporary_lhs
+// CHECK:       cf.cond_br %[[COND]], ^bb1, ^bb2
+// CHECK:     ^bb1:
+// CHECK:       cf.br ^bb3
+// CHECK:     ^bb2:
+// CHECK:       cf.br ^bb3
+// CHECK:     ^bb3:
+// CHECK:       fir.freemem
+// CHECK:       fir.freemem
+// CHECK:       return