Re: [PATCH] Fortran: intrinsic MERGE shall use all its arguments [PR107874]

[Harald Anlauf <anlauf@gmx.de>]

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Dear all,

I've committed an obvious fix for the testcase to avoid recursive I/O,
as it did cause a hang on some systems:

https://gcc.gnu.org/g:36a4ee406b95ae24a59b8b3f8ebe29af6fd5261e

Confirmed by Jerry that this resolves his issue.
See also attached.

Thanks,
Harald

Am 29.11.22 um 09:08 schrieb Paul Richard Thomas via Gcc-patches:
> Hi Harald,
>
> It looks good to me.
>
> Thanks to you and Steve for the patch.
>
> Paul
>
>
> On Mon, 28 Nov 2022 at 20:05, Harald Anlauf via Fortran <fortran@gcc.gnu.org>
> wrote:
>
>> Dear all,
>>
>> as reported, the Fortran standard requires all actual argument
>> expressions to be evaluated (e.g. F2018:15.5.3).
>>
>> There were two cases for intrinsic MERGE where we failed to do so:
>>
>> - non-constant mask; Steve provided the patch
>>
>> - constant scalar mask; we need to be careful to simplify only if
>>    the argument on the "other" path is known to be constant so that
>>    it does not have side-effects and can be immediately removed.
>>
>> The latter change needed a correction of a sub-test of testcase
>> merge_init_expr_2.f90, which should not have been simplified
>> the way the original author assumed.  I decided to modify the
>> test in such way that simplification is valid and provides
>> the expect pattern.
>>
>> Regtested on x86_64-pc-linux-gnu.  OK for mainline?
>>
>> Thanks,
>> Harald
>>
>
>

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From 36a4ee406b95ae24a59b8b3f8ebe29af6fd5261e Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Fri, 2 Dec 2022 22:30:16 +0100
Subject: [PATCH] Fortran: intrinsic MERGE shall use all its arguments
 [PR107874]

gcc/testsuite/ChangeLog:

	PR fortran/107874
	* gfortran.dg/merge_1.f90: Avoid recursive I/O.
---
 gcc/testsuite/gfortran.dg/merge_1.f90 | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/gcc/testsuite/gfortran.dg/merge_1.f90 b/gcc/testsuite/gfortran.dg/merge_1.f90
index abbc2276b1c..437b13a8d3f 100644
--- a/gcc/testsuite/gfortran.dg/merge_1.f90
+++ b/gcc/testsuite/gfortran.dg/merge_1.f90
@@ -7,32 +7,40 @@ program testmerge9
   integer :: i
   logical :: x(2) = (/.true., .false./)
   logical :: called(2)
+  logical :: y
 
   ! At run-time all arguments shall be evaluated
   do i = 1,2
      called = .false.
-     print *, merge (tstuff(), fstuff(), x(i))
+     y = merge (tstuff(), fstuff(), x(i))
+     print *, y
      if (any (.not. called)) stop 1
   end do
 
   ! Compile-time simplification shall not drop non-constant args
   called = .false.
-  print *, merge (tstuff(),fstuff(),.true.)
+  y = merge (tstuff(),fstuff(),.true.)
+  print *, y
   if (any (.not. called)) stop 2
   called = .false.
-  print *, merge (tstuff(),fstuff(),.false.)
+  y = merge (tstuff(),fstuff(),.false.)
+  print *, y
   if (any (.not. called)) stop 3
   called = .false.
-  print *, merge (tstuff(),.false.,.true.)
+  y = merge (tstuff(),.false.,.true.)
+  print *, y
   if (any (called .neqv. [.true.,.false.])) stop 4
   called = .false.
-  print *, merge (tstuff(),.false.,.false.)
+  y = merge (tstuff(),.false.,.false.)
+  print *, y
   if (any (called .neqv. [.true.,.false.])) stop 5
   called = .false.
-  print *, merge (.true.,fstuff(),.true.)
+  y = merge (.true.,fstuff(),.true.)
+  print *, y
   if (any (called .neqv. [.false.,.true.])) stop 6
   called = .false.
-  print *, merge (.true.,fstuff(),.false.)
+  y = merge (.true.,fstuff(),.false.)
+  print *, y
   if (any (called .neqv. [.false.,.true.])) stop 7
 contains
   logical function tstuff()
-- 
2.35.3