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* [gcc(refs/users/meissner/heads/ieee)] c: Handle MEM_REF in c_fully_fold* [PR94179]
@ 2020-03-18 17:19 Michael Meissner
0 siblings, 0 replies; only message in thread
From: Michael Meissner @ 2020-03-18 17:19 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:c015ff8ccaf3ee8e4f6393679ed790ed0df92873
commit c015ff8ccaf3ee8e4f6393679ed790ed0df92873
Author: Jakub Jelinek <jakub@redhat.com>
Date: Mon Mar 16 22:58:41 2020 +0100
c: Handle MEM_REF in c_fully_fold* [PR94179]
The recent match.pd changes can generate a MEM_REF which can be seen by the
C FE folding routines. Unlike the C++ FE, they weren't expected in the C FE
yet. MEM_REF should be handled like INDIRECT_REF, except that it has two
operands rather than just one and that we should preserve the type of the
second operand. Given that it already has to be an INTEGER_CST with pointer
type, I think we are fine, the recursive call should return the INTEGER_CST
unmodified and STRIP_TYPE_NOPS will not strip anything.
2020-03-16 Jakub Jelinek <jakub@redhat.com>
PR c/94179
* c-fold.c (c_fully_fold_internal): Handle MEM_REF.
* gcc.c-torture/compile/pr94179.c: New test.
Diff:
---
gcc/c/ChangeLog | 5 +++++
gcc/c/c-fold.c | 9 +++++++++
gcc/testsuite/ChangeLog | 5 +++++
gcc/testsuite/gcc.c-torture/compile/pr94179.c | 9 +++++++++
4 files changed, 28 insertions(+)
diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index d3a3b2fc784..240859e9fed 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,8 @@
+2020-03-16 Jakub Jelinek <jakub@redhat.com>
+
+ PR c/94179
+ * c-fold.c (c_fully_fold_internal): Handle MEM_REF.
+
2020-03-13 Martin Sebor <msebor@redhat.com>
PR c/94040
diff --git a/gcc/c/c-fold.c b/gcc/c/c-fold.c
index fde2d55e579..63becfeaf2c 100644
--- a/gcc/c/c-fold.c
+++ b/gcc/c/c-fold.c
@@ -346,6 +346,7 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
case UNGT_EXPR:
case UNGE_EXPR:
case UNEQ_EXPR:
+ case MEM_REF:
/* Binary operations evaluating both arguments (increment and
decrement are binary internally in GCC). */
orig_op0 = op0 = TREE_OPERAND (expr, 0);
@@ -435,6 +436,14 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
|| TREE_CODE (TREE_TYPE (orig_op0)) == FIXED_POINT_TYPE)
&& TREE_CODE (TREE_TYPE (orig_op1)) == INTEGER_TYPE)
warn_for_div_by_zero (loc, op1);
+ if (code == MEM_REF
+ && ret != expr
+ && TREE_CODE (ret) == MEM_REF)
+ {
+ TREE_READONLY (ret) = TREE_READONLY (expr);
+ TREE_SIDE_EFFECTS (ret) = TREE_SIDE_EFFECTS (expr);
+ TREE_THIS_VOLATILE (ret) = TREE_THIS_VOLATILE (expr);
+ }
goto out;
case ADDR_EXPR:
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 3b277cecac3..f0d703369a8 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-03-16 Jakub Jelinek <jakub@redhat.com>
+
+ PR c/94179
+ * gcc.c-torture/compile/pr94179.c: New test.
+
2020-03-16 Vladimir Makarov <vmakarov@redhat.com>
PR target/94185
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr94179.c b/gcc/testsuite/gcc.c-torture/compile/pr94179.c
new file mode 100644
index 00000000000..dfe27fe61d4
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr94179.c
@@ -0,0 +1,9 @@
+/* PR c/94179 */
+
+struct S { char c, d, e[64]; } a;
+
+unsigned char *
+foo (int b)
+{
+ return (unsigned char *)((char *)&a.e[b != 0] - (char *)&((struct S *)0)->d);
+}
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