This is what I've just pushed.
-- >8 --
gcc/ChangeLog:
* match.pd (`-(-X)`, `~(~X)`, `conj(conj(X))`): Add a
NON_LVALUE_EXPR wrapper to the simplification of doubled unary
operators NEGATE_EXPR, BIT_NOT_EXPR and CONJ_EXPR.
gcc/testsuite/ChangeLog:
* gfortran.dg/non_lvalue_1.f90: New test.
---
gcc/match.pd | 6 ++--
gcc/testsuite/gfortran.dg/non_lvalue_1.f90 | 32 ++++++++++++++++++++++
2 files changed, 35 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gfortran.dg/non_lvalue_1.f90
diff --git a/gcc/match.pd b/gcc/match.pd
index 0f53c162fce..f4416d9172c 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2357,7 +2357,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
/* ~~x -> x */
(simplify
(bit_not (bit_not @0))
- @0)
+ (non_lvalue @0))
/* zero_one_valued_p will match when a value is known to be either
0 or 1 including constants 0 or 1.
@@ -4037,7 +4037,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(negate (nop_convert? (negate @1)))
(if (!TYPE_OVERFLOW_SANITIZED (type)
&& !TYPE_OVERFLOW_SANITIZED (TREE_TYPE (@1)))
- (view_convert @1)))
+ (non_lvalue (view_convert @1))))
/* We can't reassociate floating-point unless -fassociative-math
or fixed-point plus or minus because of saturation to +-Inf. */
@@ -5767,7 +5767,7 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(simplify
(conj (convert? (conj @0)))
(if (tree_nop_conversion_p (TREE_TYPE (@0), type))
- (convert @0)))
+ (non_lvalue (convert @0))))
/* conj({x,y}) -> {x,-y} */
(simplify
diff --git a/gcc/testsuite/gfortran.dg/non_lvalue_1.f90
b/gcc/testsuite/gfortran.dg/non_lvalue_1.f90
new file mode 100644
index 00000000000..61dad5a2ce1
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/non_lvalue_1.f90
@@ -0,0 +1,32 @@
+! { dg-do compile }
+! { dg-additional-options "-fdump-tree-original" }
+!
+! Check the generation of NON_LVALUE_EXPR expressions in cases where a unary
+! operator expression would simplify to a bare data reference.
+
+! A NON_LVALUE_EXPR is generated for a double negation that would simplify to
+! a bare data reference.
+function f1 (f1_arg1)
+ integer, value :: f1_arg1
+ integer :: f1
+ f1 = -(-f1_arg1)
+end function
+! { dg-final { scan-tree-dump "__result_f1 = NON_LVALUE_EXPR <f1_arg1>;"
"original" } }
+
+! A NON_LVALUE_EXPR is generated for a double complement that would simplify to
+! a bare data reference.
+function f2 (f2_arg1)
+ integer, value :: f2_arg1
+ integer :: f2
+ f2 = not(not(f2_arg1))
+end function
+! { dg-final { scan-tree-dump "__result_f2 = NON_LVALUE_EXPR <f2_arg1>;"
"original" } }
+
+! A NON_LVALUE_EXPR is generated for a double complex conjugate that would
+! simplify to a bare data reference.
+function f3 (f3_arg1)
+ complex, value :: f3_arg1
+ complex :: f3
+ f3 = conjg(conjg(f3_arg1))
+end function
+! { dg-final { scan-tree-dump "__result_f3 = NON_LVALUE_EXPR <f3_arg1>;"
"original" } }
--
2.47.2
