[flang] [llvm] [flang][folding] fix i(a)char folding regression (PR #155909)

Andre Kuhlenschmidt via llvm-commits llvm-commits at lists.llvm.org
Thu Aug 28 13:09:09 PDT 2025


https://github.com/akuhlens updated https://github.com/llvm/llvm-project/pull/155909

>From 34986008e136c3dedc4068910f8f96135e2a4c55 Mon Sep 17 00:00:00 2001
From: Andre Kuhlenschmidt <akuhlenschmi at nvidia.com>
Date: Thu, 28 Aug 2025 12:47:33 -0700
Subject: [PATCH 1/3] [flang][folding] fix ichar regression

---
 flang-rt/lib/runtime/io-stmt.cpp      |  2 +-
 flang/lib/Evaluate/fold-integer.cpp   | 11 ++++++-----
 flang/test/Semantics/intrinsics04.f90 | 11 ++++++++++-
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/flang-rt/lib/runtime/io-stmt.cpp b/flang-rt/lib/runtime/io-stmt.cpp
index 28149090eb169..85f0b869cb5cc 100644
--- a/flang-rt/lib/runtime/io-stmt.cpp
+++ b/flang-rt/lib/runtime/io-stmt.cpp
@@ -1109,7 +1109,7 @@ template <Direction DIR>
 bool ChildListIoStatementState<DIR>::AdvanceRecord(int n) {
 #if !defined(RT_DEVICE_AVOID_RECURSION)
   // Allow child NAMELIST input to advance
-  if (DIR == Direction::Input && this->mutableModes().inNamelist) {
+  if (DIR == Direction::Input) {
     return this->child().parent().AdvanceRecord(n);
   } else {
     return false;
diff --git a/flang/lib/Evaluate/fold-integer.cpp b/flang/lib/Evaluate/fold-integer.cpp
index 00f92d3900c32..3628497531ef1 100644
--- a/flang/lib/Evaluate/fold-integer.cpp
+++ b/flang/lib/Evaluate/fold-integer.cpp
@@ -1050,12 +1050,13 @@ Expr<Type<TypeCategory::Integer, KIND>> FoldIntrinsicFunction(
         context.messages().Say(
             "Character in intrinsic function %s must have length one"_err_en_US,
             name);
-      } else if (len.value() > 1) {
-        // Do not die, this was not checked before
-        context.Warn(common::UsageWarning::Portability,
-            "Character in intrinsic function %s should have length one"_port_en_US,
-            name);
       } else {
+        // Do not die, this was not checked before
+        if (len.value() > 1) {
+          context.Warn(common::UsageWarning::Portability,
+              "Character in intrinsic function %s should have length one"_port_en_US,
+              name);
+        }
         return common::visit(
             [&funcRef, &context, &FromInt64](const auto &str) -> Expr<T> {
               using Char = typename std::decay_t<decltype(str)>::Result;
diff --git a/flang/test/Semantics/intrinsics04.f90 b/flang/test/Semantics/intrinsics04.f90
index a7d646e5c016e..f5d7956a4bd26 100644
--- a/flang/test/Semantics/intrinsics04.f90
+++ b/flang/test/Semantics/intrinsics04.f90
@@ -1,4 +1,4 @@
-! RUN: %python %S/test_errors.py %s %flang_fc1
+! RUN: %python %S/test_errors.py %s %flang_fc1 -Wportability
 ! A potentially absent actual argument cannot require data type conversion.
 subroutine s(o,a,p)
   integer(2), intent(in), optional :: o
@@ -23,3 +23,12 @@ subroutine s(o,a,p)
   print *, min(1_2, 2_2, a) ! ok
   print *, min(1_2, 2_2, p) ! ok
 end
+
+subroutine ichar_tests()
+  integer, parameter :: a1 = ichar('B')
+  !WARNING: Character in intrinsic function ichar should have length one [-Wportability]
+  integer, parameter :: a = ichar('B ')
+  !ERROR: Character in intrinsic function ichar must have length one
+  !ERROR: Must be a constant value
+  integer, parameter :: a3 = ichar('')
+end subroutine

>From 9fa048e88522000ead06291acd6c24ce7bcba03e Mon Sep 17 00:00:00 2001
From: Andre Kuhlenschmidt <akuhlenschmi at nvidia.com>
Date: Thu, 28 Aug 2025 12:55:25 -0700
Subject: [PATCH 2/3] remove accidental commit and add negative test

---
 flang-rt/lib/runtime/io-stmt.cpp      | 2 +-
 flang/test/Semantics/intrinsics03.f90 | 9 +++++++++
 flang/test/Semantics/intrinsics04.f90 | 2 +-
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/flang-rt/lib/runtime/io-stmt.cpp b/flang-rt/lib/runtime/io-stmt.cpp
index 85f0b869cb5cc..28149090eb169 100644
--- a/flang-rt/lib/runtime/io-stmt.cpp
+++ b/flang-rt/lib/runtime/io-stmt.cpp
@@ -1109,7 +1109,7 @@ template <Direction DIR>
 bool ChildListIoStatementState<DIR>::AdvanceRecord(int n) {
 #if !defined(RT_DEVICE_AVOID_RECURSION)
   // Allow child NAMELIST input to advance
-  if (DIR == Direction::Input) {
+  if (DIR == Direction::Input && this->mutableModes().inNamelist) {
     return this->child().parent().AdvanceRecord(n);
   } else {
     return false;
diff --git a/flang/test/Semantics/intrinsics03.f90 b/flang/test/Semantics/intrinsics03.f90
index 03109bc300caf..dbf0967c914fb 100644
--- a/flang/test/Semantics/intrinsics03.f90
+++ b/flang/test/Semantics/intrinsics03.f90
@@ -123,3 +123,12 @@ subroutine s4(ix)
   call s4(index3)
   call s4(index4) ! ok
 end
+
+subroutine ichar_tests()
+  integer, parameter :: a1 = ichar('B')
+  !Without -Wportability, the warning isn't emitted and the parameter is constant.
+  integer, parameter :: a2 = ichar('B ')
+  !ERROR: Character in intrinsic function ichar must have length one
+  !ERROR: Must be a constant value
+  integer, parameter :: a3 = ichar('')
+end subroutine
\ No newline at end of file
diff --git a/flang/test/Semantics/intrinsics04.f90 b/flang/test/Semantics/intrinsics04.f90
index f5d7956a4bd26..abb8fe321a572 100644
--- a/flang/test/Semantics/intrinsics04.f90
+++ b/flang/test/Semantics/intrinsics04.f90
@@ -27,7 +27,7 @@ subroutine s(o,a,p)
 subroutine ichar_tests()
   integer, parameter :: a1 = ichar('B')
   !WARNING: Character in intrinsic function ichar should have length one [-Wportability]
-  integer, parameter :: a = ichar('B ')
+  integer, parameter :: a2 = ichar('B ')
   !ERROR: Character in intrinsic function ichar must have length one
   !ERROR: Must be a constant value
   integer, parameter :: a3 = ichar('')

>From 85b2e6ecd9a05f22fc6322fa8d01ff789ab83269 Mon Sep 17 00:00:00 2001
From: Andre Kuhlenschmidt <akuhlenschmi at nvidia.com>
Date: Thu, 28 Aug 2025 13:08:56 -0700
Subject: [PATCH 3/3] add newline at end of file

---
 flang/test/Semantics/intrinsics03.f90 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/flang/test/Semantics/intrinsics03.f90 b/flang/test/Semantics/intrinsics03.f90
index dbf0967c914fb..a5b13b655cf41 100644
--- a/flang/test/Semantics/intrinsics03.f90
+++ b/flang/test/Semantics/intrinsics03.f90
@@ -131,4 +131,4 @@ subroutine ichar_tests()
   !ERROR: Character in intrinsic function ichar must have length one
   !ERROR: Must be a constant value
   integer, parameter :: a3 = ichar('')
-end subroutine
\ No newline at end of file
+end subroutine



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