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| author | Jakub Jelinek <jakub@redhat.com> | 2022-11-30 11:44:27 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2022-11-30 11:44:27 +0100 |
| commit | 7716ee1e90412f785cba20acffd59fc7461302cb (patch) | |
| tree | f374d680de88f953f4c55120b7a7187aa71bf209 | |
| parent | e0b95c2e8b771b53876321a6a0a9497619af73cd (diff) | |
| download | gcc-7716ee1e90412f785cba20acffd59fc7461302cb.zip gcc-7716ee1e90412f785cba20acffd59fc7461302cb.tar.gz gcc-7716ee1e90412f785cba20acffd59fc7461302cb.tar.bz2 | |
tree-chrec: Fix up ICE on pointer multiplication [PR107835]
r13-254-gdd3c7873a61019e9 added an optimization for {a, +, a} (x-1),
but as can be seen on the following testcase, the way it is written
where chrec_fold_multiply is called with type doesn't work for pointers:
res = build_int_cst (TREE_TYPE (x), 1);
res = chrec_fold_plus (TREE_TYPE (x), x, res);
res = chrec_convert_rhs (type, res, NULL);
res = chrec_fold_multiply (type, chrecr, res);
while what we were doing before and what is still used if the condition
doesn't match is fine:
res = chrec_convert_rhs (TREE_TYPE (chrecr), x, NULL);
res = chrec_fold_multiply (TREE_TYPE (chrecr), chrecr, res);
res = chrec_fold_plus (type, CHREC_LEFT (chrec), res);
because it performs chrec_fold_multiply on TREE_TYPE (chrecr) and converts
only afterwards.
I think the easiest fix is to ignore the new path for pointer types.
2022-11-30 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/107835
* tree-chrec.cc (chrec_apply): Don't handle "{a, +, a} (x-1)"
as "a*x" if type is a pointer type.
* gcc.c-torture/compile/pr107835.c: New test.
| -rw-r--r-- | gcc/testsuite/gcc.c-torture/compile/pr107835.c | 11 | ||||
| -rw-r--r-- | gcc/tree-chrec.cc | 3 |
2 files changed, 13 insertions, 1 deletions
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr107835.c b/gcc/testsuite/gcc.c-torture/compile/pr107835.c new file mode 100644 index 0000000..122beff --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/compile/pr107835.c @@ -0,0 +1,11 @@ +/* PR tree-optimization/107835 */ + +int * +foo (void) +{ + int *x = 0; + unsigned n = n; + for (; n; --n, ++x) + ; + return x; +} diff --git a/gcc/tree-chrec.cc b/gcc/tree-chrec.cc index 7321fb9..dcf26cb 100644 --- a/gcc/tree-chrec.cc +++ b/gcc/tree-chrec.cc @@ -622,7 +622,8 @@ chrec_apply (unsigned var, /* "{a, +, b} (x)" -> "a + b*x". */ else if (operand_equal_p (CHREC_LEFT (chrec), chrecr) && TREE_CODE (x) == PLUS_EXPR - && integer_all_onesp (TREE_OPERAND (x, 1))) + && integer_all_onesp (TREE_OPERAND (x, 1)) + && !POINTER_TYPE_P (type)) { /* We know the number of iterations can't be negative. So {a, +, a} (x-1) -> "a*x". */ |