From: Jakub Jelinek <jakub@redhat.com>
Date: Wed, 5 Jan 2022 09:45:26 +0000 (+0100)
Subject: gimple-fold: Remove incorrect folding of debug stmts [PR103691]
X-Git-Tag: basepoints/gcc-13~2092
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a4c2e62d60f47d47cdd94951e16b0de50495cdab;p=thirdparty%2Fgcc.git

gimple-fold: Remove incorrect folding of debug stmts [PR103691]

For ADDR_EXPR gimple_debug_bind_get_value fold_stmt_1 uses
maybe_canonicalize_mem_ref_addr earlier and I think that should
resolve the concerns raised in PR52329.  But folding ADDR_EXPR
operand using maybe_fold_reference and then taking address of that
looks like an invalid transformation, it can transform
  # DEBUG D.4293 => &a[0]
into
  # DEBUG D.4293 => &2.0e+0
etc., all we want to allow are the lhs folding of the operand which
maybe_fold_reference no longer does since r12-21-g0bf8cd9d5e8ac.

2022-01-05  Jakub Jelinek  <jakub@redhat.com>

	PR fortran/103691
	* gimple-fold.c (fold_stmt_1): Don't call maybe_fold_reference
	for DEBUG stmts with ADDR_EXPR gimple_debug_bind_get_value,
	it can do unwanted rhs folding like &a[0] into &2.0 etc.

	* gfortran.dg/pr103691.f90: New test.
---

diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index 80e7d89c1da4..77c551af942d 100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -6283,8 +6283,7 @@ fold_stmt_1 (gimple_stmt_iterator *gsi, bool inplace, tree (*valueize) (tree))
       if (gimple_debug_bind_p (stmt))
 	{
 	  tree val = gimple_debug_bind_get_value (stmt);
-	  if (val
-	      && REFERENCE_CLASS_P (val))
+	  if (val && REFERENCE_CLASS_P (val))
 	    {
 	      tree tem = maybe_fold_reference (val);
 	      if (tem)
@@ -6293,18 +6292,6 @@ fold_stmt_1 (gimple_stmt_iterator *gsi, bool inplace, tree (*valueize) (tree))
 		  changed = true;
 		}
 	    }
-	  else if (val
-		   && TREE_CODE (val) == ADDR_EXPR)
-	    {
-	      tree ref = TREE_OPERAND (val, 0);
-	      tree tem = maybe_fold_reference (ref);
-	      if (tem)
-		{
-		  tem = build_fold_addr_expr_with_type (tem, TREE_TYPE (val));
-		  gimple_debug_bind_set_value (stmt, tem);
-		  changed = true;
-		}
-	    }
 	}
       break;
 
diff --git a/gcc/testsuite/gfortran.dg/pr103691.f90 b/gcc/testsuite/gfortran.dg/pr103691.f90
new file mode 100644
index 000000000000..f1f551e20fa1
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr103691.f90
@@ -0,0 +1,9 @@
+! PR fortran/103691
+! { dg-do compile }
+! { dg-options "-O2 -g" }
+
+program pr103691
+  real, parameter :: a(0) = 2.0
+  real, allocatable :: b(:)
+  allocate (b, mold=a)
+end