Patchwork [Fortran] PR54556 - fix (4.6/4.7/) 4.8 regression: wrong code with implicit_pure procedures

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Submitter Tobias Burnus
Date Sept. 13, 2012, 12:35 p.m.
Message ID <5051D31F.8090408@net-b.de>
Download mbox | patch
Permalink /patch/183621/
State New
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Comments

Tobias Burnus - Sept. 13, 2012, 12:35 p.m.
gfortran wrongly marks some procedures as implicit_pure which aren't 
pure. implicit_pure exists since 2011-01-08 (= GCC 4.6), but was only 
used internally (FE optimization and trans*.c to avoid temporaries). 
Since 2012-08-28, implicit_pure also implies DECL_PURE_P.  The later 
change exposes a bug and  miscompiles CP2K.

The reason for the the bug is that gfc_impure_variable() checks at some 
point whether it is invoked in a PURE procedure. For implicit_pure 
procedures, the answer is no - thus that check never triggered. I have 
now removed the check - the callee already takes care of that. (Which is 
also implied by the function name.)

I additionally allow VALUE for implicit_pure. That's in line with PURE 
where VALUE is allowed since Fortran 2008. (I think since F2008's first 
technical corriendum.)

Build and regtested on x86-64-gnu-linux.
OK for the trunk and for the 4.6/4.7 branches?

Tobias,
who hopes that no additional implicit_pure bugs exist.
Mikael Morin - Sept. 13, 2012, 2:51 p.m.
On 13/09/2012 14:35, Tobias Burnus wrote:
> gfortran wrongly marks some procedures as implicit_pure which aren't
> pure. implicit_pure exists since 2011-01-08 (= GCC 4.6), but was only
> used internally (FE optimization and trans*.c to avoid temporaries).
> Since 2012-08-28, implicit_pure also implies DECL_PURE_P.  The later
> change exposes a bug and  miscompiles CP2K.
> 
> The reason for the the bug is that gfc_impure_variable() checks at some
> point whether it is invoked in a PURE procedure. For implicit_pure
> procedures, the answer is no - thus that check never triggered. I have
> now removed the check - the callee already takes care of that. (Which is
> also implied by the function name.)
> 
> I additionally allow VALUE for implicit_pure. That's in line with PURE
> where VALUE is allowed since Fortran 2008. (I think since F2008's first
> technical corriendum.)
> 
> Build and regtested on x86-64-gnu-linux.
> OK for the trunk and for the 4.6/4.7 branches?
> 
> Tobias,
> who hopes that no additional implicit_pure bugs exist.

OK, thanks.

Patch

2012-09-13  Tobias Burnus  <burnus@net-b.de>

	PR fortran/54556
	* resolve.c (resolve_formal_arglist): Allow VALUE arguments
	with implicit_pure.
	(gfc_impure_variable): Don't check gfc_pure such that the
	function also works for gfc_implicit_pure procedures.

2012-09-13  Tobias Burnus  <burnus@net-b.de>

	PR fortran/54556
	* gfortran.dg/implicit_pure_3.f90: New.

diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index 28eea5d..0748b6a 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -426,10 +426,12 @@  resolve_formal_arglist (gfc_symbol *proc)
 	    }
 	  else if (!sym->attr.pointer)
 	    {
-	      if (proc->attr.function && sym->attr.intent != INTENT_IN)
+	      if (proc->attr.function && sym->attr.intent != INTENT_IN
+		  && !sym->value)
 		proc->attr.implicit_pure = 0;
 
-	      if (proc->attr.subroutine && sym->attr.intent == INTENT_UNKNOWN)
+	      if (proc->attr.subroutine && sym->attr.intent == INTENT_UNKNOWN
+		  && !sym->value)
 		proc->attr.implicit_pure = 0;
 	    }
 	}
@@ -13565,10 +13567,9 @@  gfc_impure_variable (gfc_symbol *sym)
     }
 
   proc = sym->ns->proc_name;
-  if (sym->attr.dummy && gfc_pure (proc)
-	&& ((proc->attr.subroutine && sym->attr.intent == INTENT_IN)
-		||
-	     proc->attr.function))
+  if (sym->attr.dummy
+      && ((proc->attr.subroutine && sym->attr.intent == INTENT_IN)
+	  || proc->attr.function))
     return 1;
 
   /* TODO: Sort out what can be storage associated, if anything, and include
--- /dev/null	2012-09-13 07:07:28.691771313 +0200
+++ gcc/gcc/testsuite/gfortran.dg/implicit_pure_3.f90	2012-09-13 14:17:18.000000000 +0200
@@ -0,0 +1,109 @@ 
+! { dg-do compile }
+! { dg-options "-O2 -fdump-tree-optimized" }
+!
+! PR fortran/54556
+!
+! Contributed by Joost VandeVondele
+!
+MODULE parallel_rng_types
+
+  IMPLICIT NONE
+
+  ! Global parameters in this module
+  INTEGER, PARAMETER :: dp=8
+
+  TYPE rng_stream_type
+    PRIVATE
+    CHARACTER(LEN=40)             :: name
+    INTEGER                       :: distribution_type
+    REAL(KIND=dp), DIMENSION(3,2) :: bg,cg,ig
+    LOGICAL                       :: antithetic,extended_precision
+    REAL(KIND=dp)                 :: buffer
+    LOGICAL                       :: buffer_filled
+  END TYPE rng_stream_type
+
+  REAL(KIND=dp), DIMENSION(3,3) :: a1p0,a1p76,a1p127,&
+                                   a2p0,a2p76,a2p127,&
+                                   inv_a1,inv_a2
+
+  INTEGER, PARAMETER          :: GAUSSIAN = 1,&
+                                 UNIFORM  = 2
+
+  REAL(KIND=dp), PARAMETER :: norm  = 2.328306549295727688e-10_dp,&
+                              m1    = 4294967087.0_dp,&
+                              m2    = 4294944443.0_dp,&
+                              a12   = 1403580.0_dp,&
+                              a13n  = 810728.0_dp,&
+                              a21   = 527612.0_dp,&
+                              a23n  = 1370589.0_dp,&
+                              two17 = 131072.0_dp,&            ! 2**17
+                              two53 = 9007199254740992.0_dp,&  ! 2**53
+                              fact  = 5.9604644775390625e-8_dp ! 1/2**24
+
+
+CONTAINS
+
+  FUNCTION rn32(rng_stream) RESULT(u)
+
+    TYPE(rng_stream_type), POINTER           :: rng_stream
+    REAL(KIND=dp)                            :: u
+
+    INTEGER                                  :: k
+    REAL(KIND=dp)                            :: p1, p2
+
+! -------------------------------------------------------------------------
+! Component 1
+
+    p1 = a12*rng_stream%cg(2,1) - a13n*rng_stream%cg(1,1)
+    k = INT(p1/m1)
+    p1 = p1 - k*m1
+    IF (p1 < 0.0_dp) p1 = p1 + m1
+    rng_stream%cg(1,1) = rng_stream%cg(2,1)
+    rng_stream%cg(2,1) = rng_stream%cg(3,1)
+    rng_stream%cg(3,1) = p1
+
+    ! Component 2
+
+    p2 = a21*rng_stream%cg(3,2) - a23n*rng_stream%cg(1,2)
+    k = INT(p2/m2)
+    p2 = p2 - k*m2
+    IF (p2 < 0.0_dp) p2 = p2 + m2
+    rng_stream%cg(1,2) = rng_stream%cg(2,2)
+    rng_stream%cg(2,2) = rng_stream%cg(3,2)
+    rng_stream%cg(3,2) = p2
+
+    ! Combination
+
+    IF (p1 > p2) THEN
+      u = (p1 - p2)*norm
+    ELSE
+      u = (p1 - p2 + m1)*norm
+    END IF
+
+    IF (rng_stream%antithetic) u = 1.0_dp - u
+
+  END FUNCTION rn32
+
+! *****************************************************************************
+  FUNCTION rn53(rng_stream) RESULT(u)
+
+    TYPE(rng_stream_type), POINTER           :: rng_stream
+    REAL(KIND=dp)                            :: u
+
+    u = rn32(rng_stream)
+
+    IF (rng_stream%antithetic) THEN
+      u = u + (rn32(rng_stream) - 1.0_dp)*fact
+      IF (u < 0.0_dp) u = u + 1.0_dp
+    ELSE
+      u = u + rn32(rng_stream)*fact
+      IF (u >= 1.0_dp) u = u - 1.0_dp
+    END IF
+
+  END FUNCTION rn53
+
+END MODULE
+
+! { dg-final { scan-module-absence "parallel_rng_types" "IMPLICIT_PURE" } }
+! { dg-final { scan-tree-dump-times "rn32 \\(rng_stream" 3 "optimized" } }
+! { dg-final { cleanup-tree-dump "optimized" } }