From bacdd5e978dad84e9c547b0d5c7fed14b8d75157 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Thu, 13 Feb 2020 21:00:09 +0100 Subject: [PATCH] c: Fix ICE with cast to VLA [93576] The following testcase ICEs, because the PR84305 changes try to evaluate the size earlier. If size has side-effects, that is desirable, and the side-effects will actually be wrapped in a SAVE_EXPR. The problem on this testcase is that there are no side-effects, and c_fully_fold doesn't fold those COMPOUND_EXPRs to constant, and while before gimplification we unshare trees found in the expressions, the unsharing doesn't involve TYPE_SIZE etc. of used types. Gimplification is destructive though, so when we gimplify the two nested COMPOUND_EXPRs and then try to gimplify it the second time for the TYPE_SIZEs, we ICE. Now, we could use unshare_expr in what we push to *expr, SAVE_EXPRs and their operands in there aren't unshared, but I really don't see a point of evaluating expressions that don't have side-effects before, so instead this just pushes there expressions that do have side-effects. 2020-02-13 Jakub Jelinek PR c/93576 * c-decl.c (grokdeclarator): If this_size_varies, only push size into *expr if it has side effects. * gcc.dg/pr93576.c: New test. --- gcc/c/ChangeLog | 6 ++++++ gcc/c/c-decl.c | 13 ++++++++----- gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/gcc.dg/pr93576.c | 10 ++++++++++ 4 files changed, 29 insertions(+), 5 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/pr93576.c diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog index 995f315a803..e88337b18a0 100644 --- a/gcc/c/ChangeLog +++ b/gcc/c/ChangeLog @@ -1,3 +1,9 @@ +2020-02-13 Jakub Jelinek + + PR c/93576 + * c-decl.c (grokdeclarator): If this_size_varies, only push size into + *expr if it has side effects. + 2020-01-30 Jeff Law PR c/88660 diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c index 8281af7307a..1aa410db6e4 100644 --- a/gcc/c/c-decl.c +++ b/gcc/c/c-decl.c @@ -6512,11 +6512,14 @@ grokdeclarator (const struct c_declarator *declarator, } if (this_size_varies) { - if (*expr) - *expr = build2 (COMPOUND_EXPR, TREE_TYPE (size), - *expr, size); - else - *expr = size; + if (TREE_SIDE_EFFECTS (size)) + { + if (*expr) + *expr = build2 (COMPOUND_EXPR, TREE_TYPE (size), + *expr, size); + else + *expr = size; + } *expr_const_operands &= size_maybe_const; } } diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 560187c701a..a262bdde886 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-02-13 Jakub Jelinek + + PR c/93576 + * gcc.dg/pr93576.c: New test. + 2020-02-13 Sandra Loosemore * g++.dg/cpp0x/constexpr-static13.C: diff --git a/gcc/testsuite/gcc.dg/pr93576.c b/gcc/testsuite/gcc.dg/pr93576.c new file mode 100644 index 00000000000..13c34f3771f --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr93576.c @@ -0,0 +1,10 @@ +/* PR c/93576 */ +/* { dg-do compile } */ +/* { dg-options "" } */ + +void +foo (void) +{ + int b[] = { 0 }; + (char (*)[(1, 7, 2)]) 0; +} -- 2.30.2